The dispersal of HIV-1 subtype B (HIV-1B) is a reflection of the movement of human populations in response to social, political, and geographical issues. The initial dissemination of HIV-1B outside Africa seems to have included the passive involvement of human populations from the Caribbean in spreading the virus to the United States. However, the exact pathways taken during the establishment of the pandemic in the Americas remain unclear. Here, we propose a geographical scenario for the dissemination of HIV-1B in the Americas, based on phylogenetic and genetic statistical analyses of 313 available sequences of the pol gene from 27 countries. Maximum likelihood and Bayesian inference methods were used to explore the phylogenetic relationships between HIV-1B sequences, and molecular variance estimates were analyzed to infer the genetic structure of the viral population. We found that the initial dissemination and subsequent spread of subtype B in the Americas occurred via a single introduction event in the Caribbean around 1964 (1950–1967). Phylogenetic trees present evidence of several primary outbreaks in countries in South America, directly seeded by the Caribbean epidemic. Cuba is an exception insofar as its epidemic seems to have been introduced from South America. One clade comprising isolates from different countries emerged in the most-derived branches, reflecting the intense circulation of the virus throughout the American continents. Statistical analysis supports the genetic compartmentalization of the virus among the Americas, with a close relationship between the South American and Caribbean epidemics. These findings reflect the complex establishment of the HIV-1B pandemic and contribute to our understanding between the migration process of human populations and virus diffusion.

Entry of HIV-1 into a host cell is a multi-step process, with the viral envelope gp120 and gp41 acting sequentially to mediate the viral attachment, CD4 binding, coreceptor binding, and fusion of the viral and host membranes. The emerging class of antiretroviral agents, collectively known as entry inhibitors, interfere in some of these steps. However, viral diversity has implications for possible differential responses to entry inhibitors, since envelope is the most variable of all HIV genes. Different HIV genetic forms carry in their genomes genetic signatures and polymorphisms that could alter the structure of viral proteins which are targeted by drugs, thus impairing antiretroviral binding and efficacy. This review will examine current research that describes subtype differences in envelope at the genetic level and the effects of mutations on the efficacy of current entry inhibitors.

Entry inhibitors are a class of antiretroviral (ARV) drugs that prevent HIV replication by blocking viral entry into the host cell. The investigation of naturally occurring mutations associated with entry inhibitors across subtypes is required because genetic differences between HIV-1 variants may influence the emergence of drug resistance. Despite the importance of subtype C, which predominates globally, the majority of studies include only subtype B strains. To investigate the presence of natural resistance mutations to entry inhibitors in HIV-1 subtypes B, C, and CRF31_BC strains. Eighty samples were collected from antiretroviral-naïve patients. The gp41 gene from 67 patients and the gp120 gene from 65 patients were partially sequenced. Resistance mutations to entry inhibitors Enfuvirtide, Maraviroc, and Vicriviroc were screened. ENF resistance-associated mutations of HR1 and HR2 on gp41 were not associated with any subtype. However, the major polymorphisms detected in HR1: N42S, L54M, and A67T were most prevalent in subtype C (p < 0.001). Mutations A316T and R315Q in gp120, which are related to MVC and VCV reduced susceptibility respectively, were predominant in subtype C (p < 0.05). This study shows that many more resistance-associated mutations to entry inhibitors in ARV-naïve patients occur in subtype C compared with subtype B strains. However, further studies will be necessary to elucidate if the differential genetic background of HIV subtypes can affect the efficacy of treatment with entry inhibitors.

The purpose of this exploratory study was to investigate Brazilian school teacher attitudes and approaches to biodiversity education. We aim to specifically compare the amount of native biodiversity topics as measured by teachers’ reports of their teaching emphasis. The study involved 147 teachers from all geographic regions of the country, who answered a questionnaire containing both open- and Likert scale items to compare biodiversity-related contents. Findings reveal that the concepts with the greatest emphasis from teachers are those related to environmental conservation, while the least emphasised concepts are those about Brazilian biodiversity. This seems to lead to a paradox, since conservation-effective actions depend on the place-consciousness of biodiversity. Analysis of responses revealed the following common factors that negatively affect the teaching of native biodiversity: lack of knowledge about local biota; the absence of adequate teaching materials; curriculum geared towards preparing students for national tests; excess of curricular content; and valuation of a macro/general view of biodiversity concepts rather than a native/local view. The implications of our results are important for the training of biology teachers, to improve initial and continued teacher education programmes about native biodiversity.

The central importance of evolution to all biological sciences is recognised by many authors. Despite this scientific consensus, the theory of evolution is commonly presented as one discrete topic among many in the biology curriculum. Possible reasons for this scenario include discomfort with the content, ideological opposition and teachers’ difficulties in concepts identified as essential for the understanding of evolution. In evolution education, there is a well-established literature on these aspects, but little has been discussed about the historical and philosophical issues concerning the challenges to the centrality of evolution in biology teaching. In this article, I argue that evolution at both basic and higher education levels is strongly based on the original evolutionary synthesis, with a focus on population genetics, and this is one of the reasons for the failure in establishing the centrality of evolution in biology teaching. Given the diversity and complexity of contemporary evolution theory, a more pluralistic perspective to evolutionary teaching is required. I propose that a causally pluralistic evolutionary worldview, which expands the range of causal factors contributing to evolutionary change, is essential when it comes to establishing the centrality of evolution in biology teaching.