12 research outputs found
Raman spectroscopy analysis of Paleolithic industry from Guadalteba terrace river, Campillos (Guadalteba county, Southern of Iberian Peninsula)
Artículo sobre la aplicación de la espectroscopía ramán a los materiales de la terraza fluvial del Río Guadalteba, en Campillos
Evolution of host-plant associations and biogeographic patterns on a global scale within the oak gall wasps
Co-evolutionary interactions between insect herbivores and their host plants underlie much contemporary biodiversity and are vital to assembly of natural ecosystems. Assemblages of galls on oaks induced by Cynipini wasps (Hymenoptera: Cynipidae) occur across much of the Northern Hemisphere, their diversity peaking in the Nearctic and on white oaks (Quercus section Quercus). However, the evolutionary history of the clade has been debated with respect to geographic origins, direction and timings of dispersal events, and shifts in host plant associations. We examined these questions using a global-scale, 6-gene phylogeny of 430 Cynipini species and a dataset of their associated host plants encompassing all eight sections within Quercus plus five Fagaceae genera. Likelihood-based ancestral state reconstructions demonstrate a Nearctic origin of the Cynipini followed by repeated colonisations of the Palearctic via both westwards and eastwards dispersal. These inferences are robust to bias in taxon sampling across continents and the inclusion of Protobalandricus as the sister lineage to Cynipini sensu stricto. Likewise, the association with white oaks is probably ancestral and has been retained by many Cynipini lineages. However, host shifts to other sections within Quercus and related Fagaceae genera are widely distributed across the cynipid phylogeny. They are associated with both global-scale range shifts and within-bioregion exploitation of alternative hosts, and their frequency typically correlates with host-plant relatedness. These findings highlight the evolutionary success of cynipids on white oak hosts and the connectedness of continental assemblages of gall wasps over evolutionary time
Combined Raman spectroscopic and Rietveld analyses as a useful and nondestructive approach to studying flint raw materials at prehistoric archaeological sites
Artículo sobre análisis de espectroscopía
Interferon-gamma ameliorates experimental autoimmune encephalomyelitis by inducing homeostatic adaptation of microglia
Compelling evidence has shown that interferon (IFN)-γ has dual effects in multiple sclerosis and in its animal model of experimental autoimmune encephalomyelitis (EAE), with results supporting both a pathogenic and beneficial function. However, the mechanisms whereby IFN-γ may promote neuroprotection in EAE and its effects on central nervous system (CNS)-resident cells have remained an enigma for more than 30 years. In this study, the impact of IFN-γ at the peak of EAE, its effects on CNS infiltrating myeloid cells (MC) and microglia (MG), and the underlying cellular and molecular mechanisms were investigated. IFN-γ administration resulted in disease amelioration and attenuation of neuroinflammation associated with significantly lower frequencies of CNS CD11b+ myeloid cells and less infiltration of inflammatory cells and demyelination. A significant reduction in activated MG and enhanced resting MG was determined by flow cytometry and immunohistrochemistry. Primary MC/MG cultures obtained from the spinal cord of IFN-γ-treated EAE mice that were ex vivo re-stimulated with a low dose (1 ng/ml) of IFN-γ and neuroantigen, promoted a significantly higher induction of CD4+ regulatory T (Treg) cells associated with increased transforming growth factor (TGF)-β secretion. Additionally, IFN-γ-treated primary MC/MG cultures produced significantly lower nitrite in response to LPS challenge than control MC/MG. IFN-γ-treated EAE mice had a significantly higher frequency of CX3CR1high MC/MG and expressed lower levels of program death ligand 1 (PD-L1) than PBS-treated mice. Most CX3CR1highPD-L1lowCD11b+Ly6G- cells expressed MG markers (Tmem119, Sall2, and P2ry12), indicating that they represented an enriched MG subset (CX3CR1highPD-L1low MG). Amelioration of clinical symptoms and induction of CX3CR1highPD-L1low MG by IFN-γ were dependent on STAT-1. RNA-seq analyses revealed that in vivo treatment with IFN-γ promoted the induction of homeostatic CX3CR1highPD-L1low MG, upregulating the expression of genes associated with tolerogenic and anti-inflammatory roles and down-regulating pro-inflammatory genes. These analyses highlight the master role that IFN-γ plays in regulating microglial activity and provide new insights into the cellular and molecular mechanisms involved in the therapeutic activity of IFN-γ in EAE
Unexpected high diversity of galling insects in the Amazonian upper canopy: The savanna out there
A relatively large number of studies reassert the strong relationship between galling insect diversity and extreme hydric and thermal status in some habitats, and an overall pattern of a greater number of galling species in the understory of scleromorphic vegetation. We compared galling insect diversity in the forest canopy and its relationship with tree richness among upland terra firme, várzea, and igapó floodplains in Amazonia, Brazil. The soils of these forest types have highly different hydric and nutritional status. Overall, we examined the upper layer of 1,091 tree crowns. Galling species richness and abundance were higher in terra firme forests compared to várzea and igapó forests. GLM-ANCOVA models revealed that the number of tree species sampled in each forest type was determinant in the gall-forming insect diversity. The ratio between galling insect richness and number of tree species sampled (GIR/TSS ratio) was higher in the terra firme forest and in seasonally flooded igapó, while the várzea presented the lowest GIR/TSS ratio. In this study, we recorded unprecedented values of galling species diversity and abundance per sampling point. The GIR/TSS ratio from várzea was approximately 2.5 times higher than the highest value of this ratio ever reported in the literature. Based on this fact, we ascertained that várzea and igapó floodplain forests (with lower GIA and GIR), together with the speciose terra firme galling community emerge as the gall diversity apex landscape among all biogeographic regions already investigated. Contrary to expectation, our results also support the "harsh environment hypothesis", and unveil the Amazonian upper canopy as similar to vegetation habitats, hygrothermically stressed environments with temperature at lethal limits and high levels of leaf sclerophylly. © 2014 Julião et al
The paleolithic site Sima de las Palomas de Teba, Southern Spain. Site formation processes and chronostratigraphy.
Abstract (The Palaeolithic site Sima de las Palomas de Teba, Southern Spain –Site formation processes and chronostratigraphy): The rockshelter sequence consists of 6 m thick stone-rich silty clay loam including several archaeological levels with artefacts of Mousterian affinity, bone and charcoal. Stratigraphy and site formation processes were characterised by sedimentological, geochemical and micromorphological investigations. Sediments were dated using IRSL and OSL and the time of the last heating of burnt silex using TL. At the base of the sequence, sediment units 10 and 9 are in-situ deposits recording intensive occupation. Luminescence dating places these layers either before 33 ka (IRSL, OSL) or before 43 ka (TL).The occupation ends with a rockfall (unit 8), followed by archaeologically sterile sediments (unit 7). Mousterian occupation is again documented in scattered artefacts of units 6 to 4 which might be affected by reworking. IRSL age estimates indicated sediment deposition before 15 ka. The sequence ends with a dung rich Holocene layer including a fragment of a human mandible dated to 4032 ± 39 BP. Overall, the sequence represents an important new site for studying the presence of Neanderthals in Southern Spain