Adaptive Ecological Knowledge among the Ndjuka maroons of French Guiana; A case study of two ‘invasive species’: Melaleuca quinquenervia and Acacia mangium

Background: To understand how local ecological knowledge changes and adapts, here in the case of the recent introduction of plant species, we report the knowledge and perceptions of the Ndjuka (Maroon) of French Guiana concerning two tree species, Acacia mangium and niaouli(Melaleuca quinquenervia), which are categorized as “invasive alien plants” in the savannas of their territory. Methods: To this end, semi-structured interviews were conducted between April and July 2022, using a pre-designed questionnaire, plant samples and photographs. The uses, local ecological knowledge, and representations of these species were surveyed among populations of Maroon origin in western French Guiana. All responses to closed questions collected during the field survey were compiled into an Excel spreadsheet in order to perform quantitative analyses, including the calculation of use reports (URs). Results: It appears that the local populations have integrated these two plant species, which are named, used and even traded, into their knowledge systems. On the other hand, neither foreignness nor invasiveness seem to be relevant concepts in the perspective of the informants. The usefulness of these plants is the determining factor of their integration into the Ndjuka medicinal flora, thus resulting in the adaptation of their local ecological knowledge. Conclusion: In addition to highlighting the need for the integration of the discourse of local stakeholders into the management of "invasive alien species”, this study also allows us to observe the forms of adaptation that are set in motion by the arrival of a new species, particularly within populations that are themselves the result of recent migrations. Our results furthermore indicate that such adaptations of local ecological knowledge can occur very quickly

Some Jellyfish Like It Hot!

When you go to the beach, it might seem like there are more jellyfish every summer. Is this true? We study the barrel jellyfish, which lives in the Mediterranean and Black Seas. Since the end of the XIX century, many scientists and interested members of the public have been recording the sightings of this jellyfish along the coasts. We collected this information to see whether jellyfish numbers are increasing with the warming of the ocean waters. We found that, due to the warming of the sea caused by climate change, the barrel jellyfish are appearing earlier in the year, and there are greater numbers of barrel jellyfish in some regions now compared with years past. Although other factors, such as food, predators, or habitat changes may also affect marine species, our results indicate that ocean warming could have direct effects on living organisms, changing the functioning of marine ecosystems

Stem-cell-derived human microglia transplanted in mouse brain to study human disease

Although genetics highlights the role of microglia in Alzheimer's disease, one-third of putative Alzheimer's disease risk genes lack adequate mouse orthologs. Here we successfully engraft human microglia derived from embryonic stem cells in the mouse brain. The cells recapitulate transcriptionally human primary microglia ex vivo and show expression of human-specific Alzheimer's disease risk genes. Oligomeric amyloid-β induces a divergent response in human versus mouse microglia. This model can be used to study the role of microglia in neurological diseases.status: publishe

Stem-cell-derived human microglia transplanted in mouse brain to study human disease

Although genetics highlights the role of microglia in Alzheimer's disease, one-third of putative Alzheimer's disease risk genes lack adequate mouse orthologs. Here we successfully engraft human microglia derived from embryonic stem cells in the mouse brain. The cells recapitulate transcriptionally human primary microglia ex vivo and show expression of human-specific Alzheimer's disease risk genes. Oligomeric amyloid-β induces a divergent response in human versus mouse microglia. This model can be used to study the role of microglia in neurological diseases.</p