Sub-chronic iron overload triggers oxidative stress development in rat brain: implications for cell protection

This work was aimed to test the hypothesis that sub-chronic administration of iron-dextran (Fe-dextran) (six doses of 50 mg Fe-dextran/kg) to rats triggers a transient oxidative stress in brain and mechanisms of cellular antioxidant defence. After 2 h of administration of the 6th dose, a significant increase of total Fe, the labile Fe pool (LIP), the lipid radical (LR^?)/α-tocopherol (α-T) content ratio were observed, as compared to values in control brain homogenates. The ascorbyl radical (A^?)/ascorbate (AH^?) content ratio and the oxidation rate of 2′,7′-dichlorodihidrofluorescein (DCFH-DA) were significantly higher in Fe-dextran treated rats, as compared to values in brain from control rats after 4 h treatment. An increase in both catalase (CAT) and superoxide dismutase (SOD) activity was observed at 8 and 1–2 h, respectively. No significant changes were detected in the nuclear factor-κB (NF-κB) levels in nuclear extracts from rat brains after 1–8 h of Fe-dextran administration. After 2 h of Fe administration Fe concentration in cortex, striatum and hippocampus was significantly increased as compared to the same areas from control animals. Both, CAT and SOD activities were significantly increased in cortex after Fe administration over control values, without changes in striatum and hippocampus. Taken as a whole, sub-chronic Fe administration enhances the steady state concentration of Fe in the brain LIP that favors the settlement of an initial oxidative stress condition, both at hydrophilic and lipophilic compartments, resulting in cellular protection evidenced by antioxidant enzyme upregulation.     

Death among primates: a critical review of non‐human primate interactions towards their dead and dying

For the past two centuries, non‐human primates have been reported to inspect, protect, retrieve, carry or drag the dead bodies of their conspecifics and, for nearly the same amount of time, sparse scientific attention has been paid to such behaviours. Given that there exists a considerable gap in the fossil and archaeological record concerning how early hominins might have interacted with their dead, extant primates may provide valuable insight into how and in which contexts thanatological behaviours would have occurred. First, we outline a comprehensive history of comparative thanatology in non‐human primates, from the earliest accounts to the present, uncovering the interpretations of previous researchers and their contributions to the field of primate thanatology. Many of the typical behavioural patterns towards the dead seen in the past are consistent with those observed today. Second, we review recent evidence of thanatological responses and organise it into distinct terminologies: direct interactions (physical contact with the corpse) and secondary interactions (guarding the corpse, vigils and visitations). Third, we provide a critical evaluation regarding the form and function of the behavioural and emotional aspects of these responses towards infants and adults, also comparing them with non‐conspecifics. We suggest that thanatological interactions: promote a faster re‐categorisation from living to dead, decrease costly vigilant/caregiving behaviours, are crucial to the management of grieving responses, update position in the group's hierarchy, and accelerate the formation of new social bonds. Fourth, we propose an integrated model of Life‐Death Awareness, whereupon neural circuitry dedicated towards detecting life, i.e. the agency system (animate agency, intentional agency, mentalistic agency) works with a corresponding system that interacts with it on a decision‐making level (animate/inanimate distinction, living/dead discrimination, death awareness). Theoretically, both systems are governed by specific cognitive mechanisms (perceptual categories, associative concepts and high‐order reasoning, respectively). Fifth, we present an evolutionary timeline from rudimentary thanatological responses likely occurring in earlier non‐human primates during the Eocene to the more elaborate mortuary practices attributed to genus Homo throughout the Pleistocene. Finally, we discuss the importance of detailed reports on primate thanatology and propose several empirical avenues to shed further light on this topic. This review expands and builds upon previous attempts to evaluate the body of knowledge on this subject, providing an integrative perspective and bringing together different fields of research to detail the evolutionary, sensory/cognitive, developmental and historical/archaeological aspects of primate thanatology. Considering all these findings and given their cognitive abilities, we argue that non‐human primates are capable of an implicit awareness of death.     

Rapid identification and interpretation of gene–environment associations using the new R.SamBada landscape genomics pipeline

sam βada is a genome–environment association software, designed to search for signatures of local adaptation. However, pre‐ and postprocessing of data can be labour‐intensive, preventing wider uptake of the method. We have now developed R.SamBada, an r ‐package providing a pipeline for landscape genomic analysis based on sam βada , spanning from the retrieval of environmental conditions at sampling locations to gene annotation using the Ensembl genome browser. As a result, R.SamBada standardizes the landscape genomics pipeline and eases the search for candidate genes of local adaptation, enhancing reproducibility of landscape genomic studies. The efficiency and power of the pipeline is illustrated using two examples: sheep populations from Morocco with no evident population structure and Lidia cattle from Spain displaying population substructuring. In both cases, R.SamBada enabled rapid identification and interpretation of candidate genes, which are further discussed in the light of local adaptation. The package is available in the r CRAN package repository and on GitHub (github.com/SolangeD/R.SamBada).     

Multiple stressor effects on coral reef ecosystems

Global climate change has profound implications on species distributions and ecosystem functioning. In the coastal zone, ecological responses may be driven by various biogeochemical and physical environmental factors. Synergistic interactions can occur when the combined effects of stressors exceed their individual effects. The Red Sea, characterized by strong gradients in temperature, salinity, and nutrients along the latitudinal axis provides a unique opportunity to study ecological responses over a range of these environmental variables. Using multiple linear regression models integrating in situ, satellite and oceanographic data, we investigated the response of coral reef taxa to local stressors and recent climate variability. Taxa and functional groups responded to a combination of climate (temperature, salinity, air‐sea heat fluxes, irradiance, wind speed), fishing pressure and biogeochemical (chlorophyll a and nutrients ‐ phosphate, nitrate, nitrite) factors. The regression model for each species showed interactive effects of climate, fishing pressure and nutrient variables. The nature of the effects (antagonistic or synergistic) was dependent on the species and stressor pair. Variables consistently associated with the highest number of synergistic interactions included heat flux terms, temperature, and wind speed followed by fishing pressure. Hard corals and coralline algae abundance were sensitive to changing environmental conditions where synergistic interactions decreased their percentage cover. These synergistic interactions suggest that the negative effects of fishing pressure and eutrophication may exacerbate the impact of climate change on corals. A high number of interactions were also recorded for algae, however for this group, synergistic interactions increased algal abundance. This study is unique in applying regression analysis to multiple environmental variables simultaneously to understand stressor interactions in the field. The observed responses have important implications for understanding climate change impacts on marine ecosystems and whether managing local stressors, such as nutrient enrichment and fishing activities, may help mitigate global drivers of change.     

Connectivity-Mediated Ecohydrological Feedbacks and Regime Shifts in Drylands

Ecosystems - Identified as essential mechanisms promoting alternative stable states, positive feedbacks have been the focus of most former studies on the potential for catastrophic shifts in...     

Operationalisation and application of water supply mix (WSmix) at worldwide scale: how does WSmix influence the environmental profile of water supply for different users?

The International Journal of Life Cycle Assessment - A worldwide-regionalized water supply mix (WSmix) has been developed for use in life cycle assessment (LCA) studies. The WSmix is the...