Biology subjects

Escobar-Sierra, C.

Publications and source records attributed to Escobar-Sierra, C..

4 recordsLinked to original sources

bioRxiv2024

Navigating the Urban River: Transcriptomic Responses of Freshwater Fish to Multiple Anthropogenic Stressors

Urbanization imposes multiple anthropogenic stressors on freshwater ecosystems, affecting aquatic species physiological responses. This study explores the transcriptomic responses of the freshwater fish Cottus rhenanus to various stressors in an urban river system. RNA sequencing of fish from multiple stations revealed significant seasonal variations in gene expression, with a higher number of differentially expressed genes (DEGs) observed in the summer. Fish at the station experiencing the highest anthropogenic pressure showed notable responses, particularly during warmer months, with enriched pathways related to metabolism, oxidative stress, and immune responses. Key findings include the activation of metabolic stress pathways and immune system genes, such as IL-17 and MAPK pathways, influenced by high temperatures, salinity, and low oxygen levels. Pathway enrichment analyses highlight the impact of temperature and salinity on oxidative stress and osmoregulation, revealing the critical role of the transportome in adapting to salinity changes. These findings showcase the complex interactions between stressors and physiological responses, emphasizing the need for integrated conservation strategies to manage urban stream ecosystems.

molecular biology↗

bioRxiv2024

Global thermal tolerance of freshwater invertebrates and fish

Scientists have investigated the thermal tolerance of organisms for centuries, yet the field has not lost relevance as the environmental threats of thermal pollution and global change sharpen the need to understand the thermal vulnerability of organisms in landscapes increasingly subjected to multiple stressors. Freshwater fish and especially invertebrates are greatly underrepresented in recent large-scale compilations of thermal tolerance, despite the importance of freshwater habitats as a crucial resource and biodiversity havens. This inspired us to create a thermal tolerance database for these organisms that includes literature from 1900 until the present day sourced from five languages to counteract geographic bias, and 395 thermal tolerance tests conducted with additional stressors present. The database contains over 5000 records for over 800 species, including 452 invertebrates, providing a valuable resource to test hypotheses on thermal risks to freshwater organisms in present and future environments, and how these might change in multiple stressor scenarios.

ecology↗

bioRxiv2023

Unravelling the molecular mechanisms of fish salinity adaptation in the face of multiple stressors: A comparative multi-tissue transcriptomic study in the Llobregat River, Barcelona, Spain

Freshwater salinization poses a growing global environmental concern, introducing complex chemical cocktails and jeopardizing freshwater biodiversity, particularly fish populations. This research aimed to elucidate the molecular foundations of salinity adaptation in a non-native minnow species (Phoxinus septimaniae x P. dragarum) exposed to saline effluents from potash mines in the Llobregat River, Barcelona, Spain. Employing high-throughput mRNA sequencing and differential gene expression analyses, we examined brain, gills, and liver tissues collected from fish at two stations (upstream and downstream of saline effluent discharge). Salinization markedly influenced global gene expression profiles, with the brain exhibiting the most differentially expressed genes, emphasizing its unique sensitivity to salinity fluctuations. Pathway analyses revealed the expected enrichment of ion transport and osmoregulation pathways across all tissues. Furthermore, tissue-specific pathways associated with stress, reproduction, growth, immune responses, methylation, and neurological development were identified in the context of salinization. Rigorous validation of RNA-seq data through quantitative PCR (qPCR) underscored the robustness and consistency of our findings across platforms. This investigation unveils intricate molecular mechanisms steering salinity adaptation in non-native minnows confronting diverse environmental stressors. Advancing our comprehension of genomic responses to salinity changes, our study provides crucial insights into the adaptive strategies of aquatic organisms grappling with freshwater salinization. This comprehensive analysis sheds light on the underlying genetic and physiological mechanisms governing fish adaptation in salinity-stressed environments, offering essential knowledge for the conservation and management of freshwater ecosystems facing escalating salinization pressures.

molecular biology↗

bioRxiv2023

Field application of de novo transcriptomic analysis to evaluate the effects of sublethal freshwater salinization on Gasterosteus aculeatus in urban streams

Freshwater salinization poses global challenges for aquatic organisms, impacting their physiology and ecology. However, current salinization research predominantly focuses on mortality endpoints in limited model species, overlooking the sublethal effects on a broader spectrum of organisms and the exploration of adaptive mechanisms and pathways under natural field conditions. To address these gaps, we conducted high-throughput sequencing transcriptomic analysis on the gill tissue of the euryhaline fish Gasterosteus aculeatus, investigating its molecular response to salinity stress in the highly urbanized river Boye, Germany. We found that even sublethal concentrations of chloride led to the activation of the energetically costly osmoregulatory system in G. aculeatus, evidenced by the differential expression of genes related to osmoregulation. Our enrichment analysis revealed differentially expressed genes (DEGs) related to transmembrane transport and regulation of transport and other osmoregulation pathways, which aligns with the crucial role of these pathways in maintaining biological homeostasis. Notably, we identified candidate genes involved in increased osmoregulatory activity under salinity stress, including those responsible for moving ions across membranes: ion channels, ion pumps, and ion transporters. Particularly, genes from the solute carrier family SLC, aquaporin AQP1, chloride channel CLC7, ATP-binding cassette transporter ABCE1, and ATPases member ATAD2 exhibited prominent differential expression. These findings provide insights into the molecular mechanisms underlying the adaptive response of euryhaline fish to salinity stress and have implications for their conservation and management in the face of freshwater salinization.

molecular biology↗