RESUMO
MacLean and colleagues recently published a very elegant analysis demonstrating that SARS-CoV-2 carries signs of positive selection and that it was already adapted to humans prior to the emergence of COVID-19. Using the Spillover theory as a reference model for zoonotic emergence, they conclude that SARS-CoV-2 must have acquired this human adaptation in bats. We reinterpreted the data from MacLean et al. using a different model of zoonotic emergence as reference, the Circulation model. The use of the Circulation model provides a more parsimonious interpretation showing that this adaptation to humans occurs in the human population after primo infection.
RESUMO
Filarial nematode species can host Wolbachia bacterial endosymbionts. To understand the symbiosis, a higher level of complexity should be considered, taking in account the tripartite association between Wolbachia, filariae and mammals. This overview article discusses the biology of Wolbachia in filariae, including their distribution and phylogeny, mechanisms of action, inflammatory consequences on mammal host and biological control implications for filariases. Potential directions for future research are also discussed.
Assuntos
Filariose/tratamento farmacológico , Filariose/microbiologia , Wolbachia/genética , Animais , Anti-Helmínticos/uso terapêutico , Artrópodes/microbiologia , Filariose/transmissão , Filarioidea/genética , Filarioidea/microbiologia , Bactérias Gram-Negativas/isolamento & purificação , Humanos , Vertebrados/parasitologia , Wuchereria bancrofti/microbiologiaRESUMO
The bacteriophage WO was recently characterized in Wolbachia, a strictly intracellular bacterium that causes several reproductive alterations in its arthropod hosts. To gain insights into the phage-Wolbachia relationships, we studied the phage presence among Wolbachia infecting four insect species sharing several Wolbachia strains, two Drosophila and two of their parasitoid wasps. Based on the phage sequence of ORF7, we identified five different phages in six Wolbachia strains. Among these five bacteriophages, some are specific for a given bacterial strain whereas others are not, but globally phage infection appears stable on a large geographical scale and across insect generations. Their specificity contrasts with the absence of congruence between Wolbachia and phage phylogenies, suggesting phage exchanges between different Wolbachia lineages.