Deforestation-induced Hybridization in Philippine Frogs Creates a Distinct Phenotype With an Inviable Genotype
Related Articles
Associations of Batrachochytrium dendrobatidis with skin bacteria and fungi on Asian amphibian hosts
Amphibian skin harbors microorganisms that are associated with the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, one of the most significant wildlife diseases known. This pathogen originated in Asia, where diverse Bd lineages exist; hence, native amphibian hosts have co-existed with Bd over long time periods. Determining the nuances of this co-existence is crucial for understanding the prevalence and spread of Bd from a microbial context. However, associations of Bd with the natural skin microbiome remain poorly understood for Asian hosts, especially in relation to skin-associated fungi. We used 16 S rRNA and fungal internal transcribed spacer (ITS) gene sequencing to characterize the skin microbiome of four native Asian amphibian species and examined the relationships between Bd infection and their skin bacterial and fungal communities; we also analyzed the correlates of the putative anti-Bd bacteria. We show that both skin bacterial and fungal community structure and composition had significant associations with infection status (Bd presence/absence) and infection intensity (frequency of Bd sequence reads). We also found that the putative anti-Bd bacterial richness was correlated with Bd infection status and infection intensity, and observed that the relative abundance of anti-Bd bacteria roughly correspond with changes in both Bd prevalence and mean infection intensity in populations. Additionally, the microbial co-occurrence network of infected frogs was significantly different from that of uninfected frogs that were characterized by more keystone nodes (connectors) and larger proportions in correlations between bacteria, suggesting stronger inter-module bacterial interactions. These results indicate that the mutual effects between Bd and skin-associated microbiome, including the interplay between bacteria and fungi, might vary with Bd infection in susceptible amphibian species. This knowledge will help in understanding the dynamics of Bd from a microbial perspective, potentially contributing to mitigate chytridiomycosis in other regions of the world.
The role of rivers in the origin and future of Amazonian biodiversity
The rich biodiversity of Amazonia is shaped geographically and ecologically by its rivers and their cycles of seasonal flooding. Anthropogenic effects, such as deforestation, infrastructure development and extreme climatic events, threaten the ecological processes sustaining Amazonian ecosystems. In this Review, we explore the coupled evolution of Amazonian rivers and biodiversity associated with terrestrial and seasonally flooded environments, integrating geological, climatic, ecological and genetic evidence. Amazonia and its fluvial environments are highly heterogeneous, and the drainage system is historically dynamic and continually evolving; as a result, the discharge, sediment load and strength of rivers as barriers to biotic dispersal has changed through time. Ecological affinities of taxa, drainage rearrangements and variations in riverine landscape caused by past climate changes have mediated the evolution of the high diversity found in modern-day Amazonia. The connected history of the region’s biodiversity and landscape provides fundamental information for mitigating current and future impacts. However, incomplete knowledge about species taxonomy, distributions, habitat use, ecological interactions and occurrence patterns limits our understanding. Partnerships with Indigenous peoples and local communities, who have close ties to land and natural resources, are key to improving knowledge generation and dissemination, enabling better impact assessments, monitoring and management of the riverine systems at risk from evolving pressures.
FISH mapping in Xenopus pygmaeus refines understanding of genomic rearrangements and reveals jumping NORs in African clawed frogs
Chromosomal rearrangements are fundamental evolutionary drivers leading to genomic diversification. African clawed frogs (genus Xenopus, subgenera Silurana and Xenopus) represent an allopolyploid model system with conserved chromosome numbers in species with the same ploidy within each subgenus. Two significant interchromosomal rearrangements have been identified: a translocation between chromosomes 9 and 2, found in subgenus Silurana, and a fusion between chromosomes 9 and 10, probably widespread in subgenus Xenopus. Here, we study the allotetraploid Xenopus pygmaeus (subgenus Xenopus) based on in-depth karyotype analysis using chromosome measurements and fluorescent in situ hybridization (FISH). We designed FISH probes for genes associated with translocation and fusion to test for the presence of the two main types of rearrangements. We also examined the locations of 5S and 28S ribosomal tandem repeats, with the former often associated with telomeric regions and the latter with nucleolus organizer regions (NORs). The translocation-associated gene mapping did not detect the translocation in X. pygmaeus, supporting the hypothesis that the translocation is restricted to Silurana, but instead identified a pericentromeric inversion on chromosome 2S. The fusion-associated gene mapping confirmed the fusion of chromosomes 9 and 10, supporting this fusion as an ancestral state in subgenus Xenopus. As expected, the 5S repeats were found predominantly in telomere regions on almost all chromosomes. The nucleolar 28S repeats were localized on chromosome 6S, a position previously found only in the closely related species X. parafraseri, whereas other, phylogenetically more distant species have NORs located on different chromosomes. We therefore hypothesize that a jumping mechanism could explain the relatively frequent changes in the location of NORs during Xenopus evolution.
Iron homeostasis and ferroptosis in muscle diseases and disorders: mechanisms and therapeutic prospects
The muscular system plays a critical role in the human body by governing skeletal movement, cardiovascular function, and the activities of digestive organs. Additionally, muscle tissues serve an endocrine function by secreting myogenic cytokines, thereby regulating metabolism throughout the entire body. Maintaining muscle function requires iron homeostasis. Recent studies suggest that disruptions in iron metabolism and ferroptosis, a form of iron-dependent cell death, are essential contributors to the progression of a wide range of muscle diseases and disorders, including sarcopenia, cardiomyopathy, and amyotrophic lateral sclerosis. Thus, a comprehensive overview of the mechanisms regulating iron metabolism and ferroptosis in these conditions is crucial for identifying potential therapeutic targets and developing new strategies for disease treatment and/or prevention. This review aims to summarize recent advances in understanding the molecular mechanisms underlying ferroptosis in the context of muscle injury, as well as associated muscle diseases and disorders. Moreover, we discuss potential targets within the ferroptosis pathway and possible strategies for managing muscle disorders. Finally, we shed new light on current limitations and future prospects for therapeutic interventions targeting ferroptosis.
Efficacy and safety of sacituzumab govitecan Trop-2-targeted antibody-drug conjugate in solid tumors and UGT1A1*28 polymorphism: a systematic review and meta-analysis
Sacituzumab govitecan (SG) is a promising Trop-2-targeted antibody-drug conjugate (ADC) approved for the treatment of metastatic triple-negative breast cancer (TNBC). Early phase clinical trials have demonstrated good clinical activity and safety profile of SG in various tumor types, albeit with differing response rates and durations. The aim of this systematic review and meta-analysis was to evaluate the clinical efficacy and toxicity of SG and the influence of UGT1A1*28 genotype in clinical trials involving solid tumors.
Responses