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"Haddad, F"
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Stability Predicts Genetic Diversity in the Brazilian Atlantic Forest Hotspot
Biodiversity hotspots, representing regions with high species endemism and conservation threat, have been mapped globally. Yet, biodiversity distribution data from within hotspots are too sparse for effective conservation in the face of rapid environmental change. Using frogs as indicators, ecological niche models under paleoclimates, and simultaneous Bayesian analyses of multispecies molecular data, we compare alternative hypotheses of assemblage-scale response to late Quaternary climate change. This reveals a hotspot within the Brazilian Atlantic forest hotspot. We show that the southern Atlantic forest was climatically unstable relative to the central region, which served as a large climatic refugium for neotropical species in the late Pleistocene. This sets new priorities for conservation in Brazil and establishes a validated approach to biodiversity prediction in other understudied, species-rich regions.
Journal Article
anuran calling repertoire in the light of social context
Frogs are immediately associated to their conspicuous vocalizations emitted during the breeding season. Therefore, many scientists were inspired to study their acoustic communication. Nowadays, many types of calls are described and we felt the need of reviewing the terminology currently and historically applied. As a result, we proposed the classification of anuran vocalization into three major categories: reproductive, aggressive, and defensive calls. These categories are subdivided according to the social context of emission mostly reflecting also acoustic differences among call types. Some call types are here proposed to be synonymies of the mostly used and inclusive terms. We also suggest terminologies for basic bioacoustical analyses, mostly applied in call descriptions. Furthermore, we present cases of complex calls, including call gradation. Finally, based on novel data (such as an unusual case of juvenile vocalizations), we discuss situations in which it is difficult to classify call types, reflecting the need of experimental studies.
Journal Article
Human monkeypox: A review of the literature
Monkeypox (MPX) has recently made international headlines for the rapid and simultaneous progression of the disease across the world. This review aims at summarizing the literature available as well as describing the evolution of the disease as it pertains to the cases today along with potential treatments and infection control strategies. To date, more than 76 countries have reported cases in more than 12,261 people. Before this, MPX was a rare zoonotic disease confined to endemic areas in Western and Central Africa with sporadic outbreaks namely in the United States, associated with the import of wild animals from Ghana. However, during the current outbreak, human-to-human transmission has become the primary mode of transmission, raising concerns for unaccounted community spread. Most of these patients did not travel to the endemic areas of Africa, suggesting possible previously underdetected community transmission. Observations from emergent cases have reported that the manifestations of the disease were sometimes atypical from what has been previously described. Young men who have sex with men seem to be the population most vulnerable to infection. Though the disease is currently perceived to be mild in its clinical course, questions that remain unclear and warrant further investigation include potential of humans harboring a genital reservoir of the virus and the possibility of airborne transmission, which has implications for infection control and health of the community at large.
Journal Article
Robotic-arm assisted total knee arthroplasty has a learning curve of seven cases for integration into the surgical workflow but no learning curve effect for accuracy of implant positioning
Purpose
The primary objective of this study was to determine the surgical team’s learning curve for robotic-arm assisted TKA through assessments of operative times, surgical team comfort levels, accuracy of implant positioning, limb alignment, and postoperative complications. Secondary objectives were to compare accuracy of implant positioning and limb alignment in conventional jig-based TKA versus robotic-arm assisted TKA.
Methods
This prospective cohort study included 60 consecutive conventional jig-based TKAs followed by 60 consecutive robotic-arm assisted TKAs performed by a single surgeon. Independent observers recorded surrogate markers of the learning curve including operative times, stress levels amongst the surgical team using the state-trait anxiety inventory (STAI) questionnaire, accuracy of implant positioning, limb alignment, and complications within 30 days of surgery. Cumulative summation (CUSUM) analyses were used to assess learning curves for operative time and STAI scores in robotic TKA.
Results
Robotic-arm assisted TKA was associated with a learning curve of seven cases for operative times (
p
= 0.01) and surgical team anxiety levels (
p
= 0.02). Cumulative robotic experience did not affect accuracy of implant positioning (n.s.) limb alignment (n.s.) posterior condylar offset ratio (n.s.) posterior tibial slope (n.s.) and joint line restoration (n.s.). Robotic TKA improved accuracy of implant positioning (
p
< 0.001) and limb alignment (
p
< 0.001) with no additional risk of postoperative complications compared to conventional manual TKA.
Conclusion
Implementation of robotic-arm assisted TKA led to increased operative times and heightened levels of anxiety amongst the surgical team for the initial seven cases but there was no learning curve for achieving the planned implant positioning. Robotic-arm assisted TKA improved accuracy of implant positioning and limb alignment compared to conventional jig-based TKA. The findings of this study will enable clinicians and healthcare professionals to better understand the impact of implementing robotic TKA on the surgical workflow, assist the safe integration of this procedure into surgical practice, and facilitate theatre planning and scheduling of operative cases during the learning phase.
Level of evidence
II.
Journal Article
Single-cell RNA sequencing and spatial transcriptomics reveal cancer-associated fibroblasts in glioblastoma with protumoral effects
Cancer-associated fibroblasts (CAFs) were presumed absent in glioblastoma given the lack of brain fibroblasts. Serial trypsinization of glioblastoma specimens yielded cells with CAF morphology and single-cell transcriptomic profiles based on their lack of copy number variations (CNVs) and elevated individual cell CAF probability scores derived from the expression of 9 CAF markers and absence of 5 markers from non-CAF stromal cells sharing features with CAFs. Cells without CNVs and with high CAF probability scores were identified in single-cell RNA-Seq of 12 patient glioblastomas. Pseudotime reconstruction revealed that immature CAFs evolved into subtypes, with mature CAFs expressing actin alpha 2, smooth muscle (ACTA2). Spatial transcriptomics from 16 patient glioblastomas confirmed CAF proximity to mesenchymal glioblastoma stem cells (GSCs), endothelial cells, and M2 macrophages. CAFs were chemotactically attracted to GSCs, and CAFs enriched GSCs. We created a resource of inferred crosstalk by mapping expression of receptors to their cognate ligands, identifying PDGF and TGF-β as mediators of GSC effects on CAFs and osteopontin and HGF as mediators of CAF-induced GSC enrichment. CAFs induced M2 macrophage polarization by producing the extra domain A (EDA) fibronectin variant that binds macrophage TLR4. Supplementing GSC-derived xenografts with CAFs enhanced in vivo tumor growth. These findings are among the first to identify glioblastoma CAFs and their GSC interactions, making them an intriguing target.
Journal Article
Genetic divergence in tropical anurans: deeper phylogeographic structure in forest specialists and in topographically complex regions
Many tropical organisms show large genetic differences among populations, yet the prevalent drivers of the underlying divergence processes are incompletely understood. We explored the effect of several habitat and natural history features (body size, macrohabitat, microhabitat, reproduction site, climatic heterogeneity, and topography) on population genetic divergence in tropical amphibians, based on a data set of 2680 DNA sequences of the mitochondrial cytochrome b gene in 39 widely distributed frog species from Brazil, Central America, Cuba, and Madagascar. Generalized linear models were implemented in an information-theoretic framework to evaluate the effects of the six predictors on genetic divergence among populations, measured as spatially corrected pairwise distances. Results indicate that topographic complexity and macrohabitat preferences have a strong effect on population divergence with species specialized to forest habitat and/or from topographically complex regions showing higher phylogeographic structure. This relationship changed after accounting for phylogenetic relatedness among taxa rendering macrohabitat preferences as the most important feature shaping genetic divergence. The remaining predictors showed negligible effects on the observed genetic divergence. A similar analysis performed using the population-scaled mutation rate (Θ) as response variable showed little effect of the predictors. Our results demonstrate greater evolutionary independence among populations of anurans from forested regions versus species from open habitats. This pattern may result from lower vagility and stringency in reproductive requirements of rainforest species. Conversely, open landscapes may offer ephemeral and unstable breeding sites suitable for vagile generalist species, resulting in reduced intraspecific divergence. Our results predict that, for a given period of time, there should be a higher chance of speciation in tropical anurans living in forests than in species adapted to open habitats.
Journal Article
Warming drives ecological community changes linked to host-associated microbiome dysbiosis
Anthropogenic climate warming affects many biological systems, ranging in scale from microbiomes to biomes. In many animals, warming-related fitness depression appears more closely linked to changes in ecological community interactions than to direct thermal stress. This biotic community framework is commonly applied to warming studies at the scale of ecosystems but is rarely applied at the scale of microbiomes. Here, we used replicated bromeliad microecosystems to show warming effects on tadpole gut microbiome dysbiosis mediated through biotic community interactions. Warming shifted environmental bacteria and arthropod community composition, with linkages to changes in microbial recruitment that promoted dysbiosis and stunted tadpole growth. Tadpole growth was more strongly associated with cascading effects of warming on gut dysbiosis than with direct warming effects or indirect effects on food resources. These results suggest that assessing warming effects on animal health requires an ecological community perspective on microbiome structure and function.Replicated bromeliad microecosystems were used to examine warming-induced community shifts and changes to tadpole gut microbiome. Tadpole growth was more strongly associated with cascading effects of warming on gut dysbiosis than with direct warming effects or indirect effects on food resources.
Journal Article
Sophisticated Communication in the Brazilian Torrent Frog Hylodes japi
Intraspecific communication in frogs plays an important role in the recognition of conspecifics in general and of potential rivals or mates in particular and therefore with relevant consequences for pre-zygotic reproductive isolation. We investigate intraspecific communication in Hylodes japi, an endemic Brazilian torrent frog with territorial males and an elaborate courtship behavior. We describe its repertoire of acoustic signals as well as one of the most complex repertoires of visual displays known in anurans, including five new visual displays. Previously unknown in frogs, we also describe a bimodal inter-sexual communication system where the female stimulates the male to emit a courtship call. As another novelty for frogs, we show that in addition to choosing which limb to signal with, males choose which of their two vocal sacs will be used for visual signaling. We explain how and why this is accomplished. Control of inflation also provides additional evidence that vocal sac movement and color must be important for visual communication, even while producing sound. Through the current knowledge on visual signaling in Neotropical torrent frogs (i.e. hylodids), we discuss and highlight the behavioral diversity in the family Hylodidae. Our findings indicate that communication in species of Hylodes is undoubtedly more sophisticated than we expected and that visual communication in anurans is more widespread than previously thought. This is especially true in tropical regions, most likely due to the higher number of species and phylogenetic groups and/or to ecological factors, such as higher microhabitat diversity.
Journal Article
Biogeographic Distribution Patterns and Their Correlates in the Diverse Frog Fauna of the Atlantic Forest Hotspot
Anurans are a highly diverse group in the Atlantic Forest hotspot (AF), yet distribution patterns and species richness gradients are not randomly distributed throughout the biome. Thus, we explore how anuran species are distributed in this complex and biodiverse hotspot, and hypothesize that this group can be distinguished by different cohesive regions. We used range maps of 497 species to obtain a presence/absence data grid, resolved to 50×50 km grain size, which was submitted to k-means clustering with v-fold cross-validation to determine the biogeographic regions. We also explored the extent to which current environmental variables, topography, and floristic structure of the AF are expected to identify the cluster patterns recognized by the k-means clustering. The biogeographic patterns found for amphibians are broadly congruent with ecoregions identified in the AF, but their edges, and sometimes the whole extent of some clusters, present much less resolved pattern compared to previous classification. We also identified that climate, topography, and vegetation structure of the AF explained a high percentage of variance of the cluster patterns identified, but the magnitude of the regression coefficients shifted regarding their importance in explaining the variance for each cluster. Specifically, we propose that the anuran fauna of the AF can be split into four biogeographic regions: a) less diverse and widely-ranged species that predominantly occur in the inland semideciduous forests; b) northern small-ranged species that presumably evolved within the Pleistocene forest refugia; c) highly diverse and small-ranged species from the southeastern Brazilian mountain chain and its adjacent semideciduous forest; and d) southern species from the Araucaria forest. Finally, the high congruence among the cluster patterns and previous eco-regions identified for the AF suggests that preserving the underlying habitat structure helps to preserve the historical and ecological signals that underlie the geographic distribution of AF anurans.
Journal Article