Unique establishment of procephalic head segments is supported by the identification of cis-regulatory elements driving segment-specific segment polarity gene expression in Drosophila

Anterior head segmentation is governed by different regulatory mechanisms than those that control trunk segmentation in Drosophila. For segment polarity genes, both initial mode of activation as well as cross-regulatory interactions among them differ from the typical genetic circuitry in the trunk and are unique for each of the procephalic segments. In order to better understand the segment-specific gene network responsible for the procephalic expression of the earliest active segment polarity genes wingless and hedgehog, we started to identify and analyze cis-regulatory DNA elements of these genes. For hedgehog, we could identify a cis-regulatory element, ic-CRE, that mediates expression specifically in the posterior part of the intercalary segment and requires promoter-specific interaction for its function. The intercalary stripe is the last part of the metameric hedgehog expression pattern that appears during embryonic development, which probably reflects the late and distinct establishment of this segment. The identification of a cis-regulatory element that is specific for one head segment supports the mutant-based observation that the expression of segment polarity genes is governed by a unique gene network in each of the procephalic segments. This provides further indication that the anterior-most head segments represent primary segments, which are set up independently, in contrast to the secondary segments of the trunk, which resemble true repetitive units

Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

Background: PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods: We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results: We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion: The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04066881

Multiple Invasions into Freshwater by Pufferfishes (Teleostei: Tetraodontidae): A Mitogenomic Perspective

Pufferfishes of the Family Tetraodontidae are the most speciose group in the Order Tetraodontiformes and mainly inhabit coastal waters along continents. Although no members of other tetraodontiform families have fully discarded their marine lives, approximately 30 tetraodontid species spend their entire lives in freshwaters in disjunct tropical regions of South America, Central Africa, and Southeast Asia. To investigate the interrelationships of tetraodontid pufferfishes and thereby elucidate the evolutionary origins of their freshwater habitats, we performed phylogenetic analysis based on whole mitochondrial genome sequences from 50 tetraodontid species and closely related species (including 31 newly determined sequences). The resulting phylogenies reveal that the family is composed of four major lineages and that freshwater species from the different continents are independently nested in two of the four lineages. A monophyletic origin of the use of freshwater habitats was statistically rejected, and ancestral habitat reconstruction on the resulting tree demonstrates that tetraodontids independently entered freshwater habitats in different continents at least three times. Relaxed molecular-clock Bayesian divergence time estimation suggests that the timing of these invasions differs between continents, occurring at 0–10 million years ago (MA) in South America, 17–38 MA in Central Africa, and 48–78 MA in Southeast Asia. These timings are congruent with geological events that could facilitate adaptation to freshwater habitats in each continent

A distinguishing feature of Pongo upper molars and its implications for the taxonomic identification of isolated hominid teeth from the Pleistocene of Asia

The taxonomic status of isolated hominoid teeth from the Asian Pleistocene has long been controversial due to difficulties distinguishing between pongine and hominin molars given their high degree of morphometrical variation and overlap. Here, we combine nonmetric and geometric morphometric data to document a dental pattern that appears to be taxonomically diagnostic among Pongo. We focus on the protoconule, a cuspule of well‐documented evolutionary history, as well as on shape differences of the mesial fovea of the upper molars

Global Boundary Stratotype Section and Point (GSSP) for the Anthropocene Series: Where and how to look for potential candidates

International audienc

State of the art of the meiofauna of Brazilian Sandy Beaches

Abstract In Brazil, meiofauna studies began in the middle of last century, but they adopted a purely taxonomical approach, describing species from various zoological groups. After this first step, this benthic group was largely neglected until the end of the 20th century when ecological studies began. We here provide a brief review of present knowledge of the meiofauna found on Brazilian sandy beaches to provide information for ReBentos (Coastal Benthic Habitats Monitoring Network). Our methodology consisted of a bibliographic survey undertaken using different datasets (Web of ScienceTM, SCOPUS, Google Scholar and Lattes Plataform). For the survey, we considered only those studies published till early 2015. Our analysis showed that the number of meiofauna studies has increased over the last two decades, though they are mainly still concentrated on the Southeast of Brazil. These studies aim to explain the distribution pattern of the meiofauna of the intertidal region of sandy beaches. Based on the results, we presented a discussion of three main topics, i.e., (a) current knowledge of Brazilian sandy beach meiofauna, (b) sampling strategies for monitoring of the meiofauna, and (c) use of the meiofauna as a tool to assess climate change. We trust that this brief review will be useful as a starting point for the delineation of further climate change investigations into sandy beach meiofauna