Jornal de Filogenética e Biologia Evolutiva

The parallelism between the process of primary succession and the evolution of life on this planet is remarkable and conspicuous, yet never been spotted before. The order, at which each seral community appear, right from the pioneer species until the climax communities, is by the order of appearance of the respective evolutionary lineages in the tree of life. Evolutionary history of life on this planet is, in fact, a massive and ongoing process of primary succession, and I believe that is the rationale for this striking harmony. Central premise of this postulation is the idea that the plants that have been evolved to adapt to an almost naked landscape would be the first to colonize new environments. In light of this parallelism, fields of ecological succession and phylogenetic systematics can mutually compliment for resolving perplexed conundrums, and can potentially enlighten the future of life on the planet earth.

This study revisits antibiotic resistance as a source of evolutionary development in pathogenic bacteria. By taking a molecular phylogenetic approach to this inquiry, I seek to find homologous correlations in antimicrobial resistance gene families across a broad spectrum of bacteria, as to identify the possible acquisition of those genes through divergent events in evolutionary context. In order to test this, I examine the various degrees of genetic similarity in two antimicrobial resistance genomic datasets, namely aadA1 and aadA2 aminoglycoside resistance genes, among bacteria that occur in a multitude of environments. Moreover, the results from phylogenetic analysis suggests that pathogenic antibiotic resistance for aadA1 and aadA2 aminoglycoside resistance genes may have been acquired through evolutionary events with a common ancestor of a soil-dwelling bacterium.

This study presented detailed descriptions of parenchymal arrangements in the livers of 23 reptilian species using light microscopy, and extensively discussed this from a phylogenetic viewpoint. Hepatocyte sinusoidal structures (HSS) were classified into three different types: (I) the several-cell-thick plate type, (II) two-cell-thick plate type, and (III) one-cell-thick plate type. Parenchymal arrangements showed either the combined two- and one-cell-thick plate type or one-cell-thick plate type, whereas the sea snake in the sub-order Serpentes showed the several-cell-thick plate type. In the order Testudines, peripheral sinusoids near terminal portal veins were tortuous, becoming straighter toward terminal central veins. Melanomacrophages (MMs) were observed in sinusoidal capillaries in the order Testudinata, Crocodilia, and Squamata, but not in the sub-order Serpentes (except for the sea snake). This study showed that the architecture of the parenchymal arrangement was related to the phylogenetic relationship, whereas the distribution of MMs may not be. The MMs systems of turtles, alligators, and sea snakes, whose place of main habitation is underwater, may have adapted according to ecological and behavioral patterns. Based on the hepatic architecture of parenchymal arrangements and the distribution of MMs, it was suggested that reptilian livers acquired the division of three zones in the acinus.