Biology subjects

Santana, J.

Publications and source records attributed to Santana, J..

6 recordsLinked to original sources

bioRxiv2025

TOWARDS CLIMATE-SMART REWILDING: AN INTEGRATED FRAMEWORK FOR BIODIVERSITY, CLIMATE CHANGE, AND SOCIETY

The UN Decade on Ecosystem Restoration and the Kunming-Montreal Global Biodiversity Framework aim to restore 30% of degraded ecosystems. Both the IPCC and IPBES highlight the crucial role of ecosystem restoration in addressing the interconnected crises of climate change and biodiversity loss. One key restoration strategy is rewilding, which enhances ecosystem complexity with minimal human intervention. While traditional rewilding strategies often focus on benefits for biodiversity, we propose a climate-smart rewilding framework as a new approach designed to deliver climate benefits alongside biodiversity restoration. This framework seeks to integrate biodiversity, climate change adaptation and mitigation, as well as socio-economic benefits and trade-offs. We illustrate how this framework can be utilized to identify areas across Europe where rewilding could increase carbon sequestration, enhance species abilities to adapt to the velocity of climate change, and maximize wildlife-watching benefits while minimizing the costs associated with livestock-wildlife conflict. Finally, we acknowledge some limitations of climate-smart rewilding, but we argue that its adaptability and low cost render it a promising solution to the challenges facing Europe and beyond.

ecology↗

bioRxiv2024

Early transatlantic movement of horses and donkeys at Jamestown

Domestic horses and donkeys played a key role in the initial colonization of the Atlantic seaboard of the Americas, a process partially chronicled by historical records. While Spanish colonists brought horses to the Caribbean and southern latitudes earlier, the transport of domestic horses to the English colony at Jamestown, Virginia in 1606 was among the first dispersals to the eastern seaboard. Archaeozoological analysis, isotope analysis, and radiocarbon dating of identifiable domestic equid remains from two contexts associated with the initial occupation of Jamestown demonstrate intense processing and consumption of the first Jamestown horses during the "Starving Time" winter of 1609, while paleopathological data show evidence of their use in transport. Osteological, genetic, and isotopic study of these equid remains reveal the presence of at least one adult domestic donkey with mixed European and West African ancestry, possibly supplied through undocumented exchange during a trans-Atlantic stopover. These results reveal the importance of equids in the survival of early European settlers and the global connectivity of early trans-Atlantic exchange in horses and donkeys, showing Caribbean and African links in the founding livestock populations and pointing towards an important and ecologically-anchored role for donkeys in the early colonial lifeways along the Eastern seaboard.

genetics↗

bioRxiv2023

Biodiversity monitoring in Europe: user and policy needs

To implement the goals of the 2030 Global Biodiversity Framework, the European Biodiversity Strategy and the EU Green Deal, biodiversity monitoring is a pivotal instrument to achieve accountability and progress in conservation. Monitoring efforts in Europe, however, suffer from gaps and biases in taxonomy, spatial coverage, and temporal resolution, resulting in fragmented and disconnected data which does not provide sufficient evidence for policy making. To assess user and policy needs in biodiversity monitoring, we employed with EuropaBON a four-step user-centred stakeholder engagement process, including an international public stakeholder workshop, a standardised online survey, semi-structured interviews, and an expert meeting with representatives of EU member states, the European Commission and the European Environment Agency. The resulting insights into national and European biodiversity monitoring schemes identify policy needs, current challenges and potential solutions. Based on this in-depth policy and science stakeholder assessment, we recommend the establishment of a European Biodiversity Observation Network through a permanent Biodiversity Monitoring and Coordinating Centre to optimise existing observation efforts, harmonise data, and enhance our ability to predict and respond to key challenges related to biodiversity loss in a changing climate in Europe.

ecology↗

bioRxiv2022

Functional mRNA delivery to hematopoietic stem and progenitor cells in vivo.

Gene correction of hematopoietic stem cells (HSC) is a promising therapeutic approach for multiple disorders. Current methods, however, require HSC collection from patients, gene correction during ex vivo culture, and re-infusion of corrected HSC into patients conditioned with chemotherapeutic agents. These approaches are complex, and the conditioning creates toxicities. We show that a lipid nanoparticle (LNP) can deliver mRNA encoding a reporter or a gene editing protein to HSC, with one injection transfecting [~]25% of mouse HSC, and repeated doses resulting in higher editing efficiencies. We also demonstrate LNP-driven in vivo mRNA delivery to HSC in non-human primates and humanized mice. These results demonstrate a translatable approach to deliver mRNA encoding therapeutic proteins, or gene correcting tools, to HSC that do not require cell culture or toxic conditioning. One-Sentence SummaryLNP can deliver functional mRNA to mouse, non-human primate, and human HSC.

immunology↗

bioRxiv2019

Unraveling ChR2-driven stochastic Ca2+ dynamics in astrocytes - A call for new interventional paradigms

Control of astrocytes via modulation of Ca2+ oscillations using techniques like optogenetics can prove to be crucial in therapeutic intervention of a variety of neurological disorders. However, a systematic study quantifying the effect of optogenetic stimulation in astrocytes is yet to be performed. Here, we propose a novel stochastic Ca2+dynamics model that incorporates the light sensitive component - channelrhodopsin 2 (ChR2). Utilizing this model, we studied the effect of various pulsed light stimulation paradigms on astrocytes for select variants of ChR2 (wild type, ChETA, and ChRET/TC) in both an individual and a network of cells. Our results exhibited a consistent pattern of Ca2+ activity among individual cells in response to optogenetic stimulation, i.e., showing steady state regimes with increased Ca2+ basal level and Ca2+ spiking probability. Furthermore, we performed a global sensitivity analysis to assess the effect of stochasticity and variation of model parameters on astrocytic Ca2+ dynamics in the presence and absence of light stimulation, respectively. Results indicated that directing variants towards the first open state of the photo-cycle of ChR2 (o1) enhances spiking activity in astrocytes during optical stimulation. Evaluation of the effect of astrocytic ChR2 expression (heterogeneity) on Ca2+ signaling revealed that the optimal stimulation paradigm of a network does not necessarily coincide with that of an individual cell. Simulation for ChETA-incorporated astrocytes suggest that maximal activity of a single cell reduced the spiking probability of the network of astrocytes at higher degrees of ChR2 expression efficiency due to an elevation of basal Ca2+ beyond physiological levels. Collectively, the framework presented in this study provides valuable information for the selection of light stimulation paradigms that elicit optimal astrocytic activity using existing ChR2 constructs, as well as aids in the engineering of future optogenetic constructs. Author summaryOptogenetics - an avant-garde technique involves targeted delivery of light sensitive ion channels to cells. Channelrhodopsin 2 (ChR2), an algal derived light sensitive ion channel has extensively been used in neuroscience to manipulate various cell types in a guided and controlled manner. Despite being predominantly used in neurons, recent advancements have led to the expansion of the application of optogenetics in non-neuronal cell types, like astrocytes. These cells play a key role in various aspects of the central nervous system and alteration of their signaling is associated with various disorders, including epilepsy, stroke and Alzheimers disease. Hence, invaluable information for therapeutic intervention can be obtained from using optogenetics to regulate astrocytic activity in a strategic manner. Here, we propose a novel computational model to assess astrocytic response to optogenetic stimulation which implicitly accounts for the stochastic character of Ca2+ signaling in this cell type. We identified light stimulation paradigms suitable for eliciting astrocytic Ca2+ response within physiological levels in widely-used ChR2 variants and identified highly sensitive parameters in ChR2 kinetics conducive for higher probability in Ca2+ spiking. Overall, the results of this model can be used to boost astrocyte light-induced behavior prediction and the development of improved future optogenetic constructs.

neuroscience↗

bioRxiv2017

Neolithization of North Africa involved the migration of people from both the Levant and Europe

The extent to which prehistoric migrations of farmers influenced the genetic pool of western North Africans remains unclear. Archaeological evidence suggests the Neolithization process may have happened through the adoption of innovations by local Epipaleolithic communities, or by demic diffusion from the Eastern Mediterranean shores or Iberia. Here, we present the first analysis of individuals genome sequences from early and late Neolithic sites in Morocco, as well as Early Neolithic individuals from southern Iberia. We show that Early Neolithic Moroccans are distinct from any other reported ancient individuals and possess an endemic element retained in present-day Maghrebi populations, confirming a long-term genetic continuity in the region. Among ancient populations, Early Neolithic Moroccans are distantly related to Levantine Natufian hunter-gatherers ([~]9,000 BCE) and Pre-Pottery Neolithic farmers ([~]6,500 BCE). Although an expansion in Early Neolithic times is also plausible, the high divergence observed in Early Neolithic Moroccans suggests a long-term isolation and an early arrival in North Africa for this population. This scenario is consistent with early Neolithic traditions in North Africa deriving from Epipaleolithic communities who adopted certain innovations from neighbouring populations. Late Neolithic ([~]3,000 BCE) Moroccans, in contrast, share an Iberian component, supporting theories of trans-Gibraltar gene flow. Finally, the southern Iberian Early Neolithic samples share the same genetic composition as the Cardial Mediterranean Neolithic culture that reached Iberia [~]5,500 BCE. The cultural and genetic similarities of the Iberian Neolithic cultures with that of North African Neolithic sites further reinforce the model of an Iberian migration into the Maghreb.\n\nSIGNIFICANCE STATEMENTThe acquisition of agricultural techniques during the so-called Neolithic revolution has been one of the major steps forward in human history. Using next-generation sequencing and ancient DNA techniques, we directly test if Neolithization in North Africa occurred through the transmission of ideas or by demic diffusion. We show that Early Neolithic Moroccans are composed of an endemic Maghrebi element still retained in present-day North African populations and distantly related to Epipaleolithic communities from the Levant. However, late Neolithic individuals from North Africa are admixed, with a North African and a European component. Our results support the idea that the Neolithization of North Africa might have involved both the development of Epipaleolithic communities and the migration of people from Europe.

genetics↗