Reconsidering the taxonomy of the Black-Faced Uacaris, Cacajao melanocephalus group (Mammalia: Pitheciidae), from the northern Amazon Basin.

The black-faced uacaris are a poorly known group of platyrrhine monkeys from the Rio Negro basin in northwestern Amazonia. Originally described as two distinct species-Cacajao melanocephalus (Humboldt 1812) and Cacajao ouakary (Spix 1823)-from opposite banks of the Negro, they were treated as a single species until the end of the twentieth century, when molecular studies reconfirmed their status as true species. One of these studies not only nominated a third (northern) species, Cacajao ayresi Boubli et al. 2008, but also identified C. ouakary as a junior synonym of C. melanocephalus, resulting in the introduction of a new nomen, Cacajao hosomi Boubli et al. 2008. In the present study, additional evidence on morphological and zoogeographic variables is analyzed, which indicates that C. ouakary should be reinstated, and supports the nomination of a neotype of C. melanocephalus. The molecular and zoogeographic data on the species status of the ayresi form are also re-assessed, leading to the conclusion that, on the basis of the evidence available at the present time, this form should be considered a subspecies of C. melanocephalus. A new taxonomic arrangement is proposed, which recognizes two species, C. ouakary and C. melanocephalus, the latter with two subspecies, C. m. melanocephalus and C. m. ayresi.

Tumor malignancy is engaged to prokaryotic homolog toolbox.

Cancer cells display high proliferation rates and survival provided by high glycolysis, chemoresistance and radioresistance, metabolic features that appear to be activated with malignancy, and seemed to have arisen as early in evolution as in unicellular/prokaryotic organisms. Based on these assumptions, we hypothesize that aggressive phenotypes found in malignant cells may be related to acquired unicellular behavior, launched within a tumor when viral and prokaryotic homologs are overexpressed performing likely robust functions. The ensemble of these expressed viral and prokaryotic close homologs in the proteome of a tumor tissue gives them advantage over normal cells. To assess the hypothesis validity, sequences of human proteins involved in apoptosis, energetic metabolism, cell mobility and adhesion, chemo- and radio-resistance were aligned to homologs present in other life forms, excluding all eukaryotes, using PSI-BLAST, with further corroboration from data available in the literature. The analysis revealed that selected sequences of proteins involved in apoptosis and tumor suppression (as p53 and pRB) scored non-significant (E-value>0.001) with prokaryotic homologs; on the other hand, human proteins involved in cellular chemo- and radio-resistance scored highly significant with prokaryotic and viral homologs (as catalase, E-value=zero). We inferred that such upregulated and/or functionally activated proteins in aggressive malignant cells represent a toolbox of modern human homologs evolved from a similar key set that have granted survival of ancient prokaryotes against extremely harsh environments. According to what has been discussed along this analysis, high mutation rates usually hit hotspots in important conserved protein domains, allowing uncontrolled expansion of more resistant, death-evading malignant clones. That is the case of point mutations in key viral proteins affording viruses escape to chemotherapy, and human homologs of such retroviral proteins (as Ras, Akt and EGFR) can elicit the same phenotype. Furthermore, a corollary to this hypothesis presumes that target-directed anti-cancer therapy should target human protein domains of low similarity to prokaryotic homologs for a well-succeeded anti-cancer therapy.