There is a growing necessity to integrate morphological and genetic studies. This paper proposes a new technique that allows DNA extraction of arthropods while still keeping intact the entire morphology of the specimens. The technique uses Proteinase K to dissolve protein tissues and preserve the chitinous exoskeleton of specimens. The method is fast, cheap, non-toxic, and allows for good morphological preparations of specimens retaining much of their tridimensional structure. The methodology works fine with specimens preserved in different kinds of media, such as for dry (pinned) specimens, and specimens preserved in Ethanol. In addition, it allows the extraction of DNA from fresh specimens, as well as from specimens preserved for a long time. The technique works well for morphological studies alone, but allows the generation of an associated genomic library at an individual-scale. Among the advantages of the new technique is the possibility of extracting DNA from the entire specimen (necessary for the study of diseases transmitted by arthropod vectors), while still keeping the morphology intact for correct taxonomic identification. In addition, in comparison with methods that extract DNA from small tissue samples (e.g., from legs or wings), the method allows for the extraction of a larger amount of DNA and is better suited for small specimens.

Phylogenetic studies on trypanosomatid barcode using V7V8 SSU rRNA and gGAPDH gene sequences have provided support for redefining some trypanosomatid species and positioning new isolates. The genus Leishmania is a slow evolving monophyletic group and including important human pathogens. The phylogenetic relationships of this genus have been determined by the natural history of its vertebrate hosts, vector specificity, clinical manifestations, geographical distribution and molecular approaches using different markers. Thus, in an attempt to better understand the phylogenetic relationships of Leishmania species, we performed phylogenetic analysis on trypanosomatid barcode using V7V8 SSU rRNA and gGAPDH gene sequences among a large number of Leishmania species and also several Brazilian visceral Leishmania infantum chagasi isolates obtained from dogs and humans. Our phylogenetic analysis strongly suggested that Leishmania hertigi and Leishmania equatoriensis should be taxonomically revised so as to include them in the genus Endotrypanum; and supported ancient divergence of Leishmania enriettii. This, together with recent data in the literature, throws light on the discussion about the evolutionary southern supercontinent hypothesis for the origin of Leishmania ssp. and validates L. infantum chagasi from Brazil, thus clearly differentiating it from L. infantum, for the first time.

Mayaro virus (MAYV) is widely distributed throughout South America and is the etiologic agent of Mayaro fever, an acute febrile illness often presenting with arthralgic manifestations. The true incidence of MAYV infection is likely grossly underestimated because the symptomatic presentation is very similar to that of dengue fever and other acute febrile tropical diseases. We report the complete genome sequence of a MAYV isolate detected from an Acrelândia patient presenting with fever, chills, and sweating, but with no arthralgia. Results show that this isolate belongs to genotype D and is closely related to Bolivian strains. Our results suggest that the Acre/Mayaro strain is closely related to the progenitor of these Bolivian strains that were isolated between 2002 and 2006.

Summary: Eukaryotic elongation factor 1A (eEF1A) plays a central role in protein synthesis, cell growth and morphology. Malaria parasites possess two identical genes encoding eEF1A (eef1aa and eef1ab). Using pbeef1a^–Plasmodium berghei mutants that lack an eEF1a gene, we demonstrate that the level of eEF1A production affects the proliferation of blood stages and parasite fitness. Pbeef1a^– parasites can complete the vertebrate and mosquito phases of the life cycle, but the growth phase of the asexual blood stages is extended by up to 20%. Analysis of the cell cycle by flow cytometry as well as transcriptional analyses revealed that the duration of the S and M phases and the number of daughter cells produced were not detectably affected, but that the G₁ phase is elongated. Thus, as in budding yeast, a growth threshold must be achieved by blood‐stage Plasmodium parasites to permit transition from G₁ into S/M phase. Initial analyses indicate that transcriptional events associated with gametocyte development were not remarkably retarded. Insight into protein synthesis and its influence on cell proliferation might be used to generate slow‐growing (attenuated) parasites.