Territoriality of Giant Otter Groups in an Area with Seasonal Flooding

Territoriality carries costs and benefits, which are commonly affected by the spatial and temporal abundance and predictability of food, and by intruder pressure. Giant otters (Pteronura brasiliensis) live in groups that defend territories along river channels during the dry season using chemical signals, loud vocalizations and agonistic encounters. However, little is known about the territoriality of giant otters during the rainy season, when groups leave their dry season territories and follow fish dispersing into flooded areas. The objective of this study was to analyze long-term territoriality of giant otter groups in a seasonal environment. The linear extensions of the territories of 10 giant otter groups were determined based on locations of active dens, latrines and scent marks in each season. Some groups overlapped the limits of neighboring territories. The total territory extent of giant otters was correlated with group size in both seasons. The extent of exclusive territories of giant otter groups was negatively related to the number of adults present in adjacent groups. Territory fidelity ranged from 0 to 100% between seasons. Some groups maintained their territory for long periods, which demanded constant effort in marking and re-establishing their territories during the wet season. These results indicate that the defense capacity of groups had an important role in the maintenance of giant otter territories across seasons, which may also affect the reproductive success of alpha pairs.     

The Macrophage Inhibitor CNI-1493 Blocks Metastasis in a Mouse Model of Ewing Sarcoma through Inhibition of Extravasation

Metastatic Ewing Sarcoma carries a poor prognosis, and novel therapeutics to prevent and treat metastatic disease are greatly needed. Recent evidence demonstrates that tumor-associated macrophages in Ewing Sarcoma are associated with more advanced disease. While some macrophage phenotypes (M1) exhibit anti-tumor activity, distinct phenotypes (M2) may contribute to malignant progression and metastasis. In this study, we show that M2 macrophages promote Ewing Sarcoma invasion and extravasation, pointing to a potential target of anti-metastatic therapy. CNI-1493 is a selective inhibitor of macrophage function and has shown to be safe in clinical trials as an anti-inflammatory agent. In a xenograft mouse model of metastatic Ewing Sarcoma, CNI-1493 treatment dramatically reduces metastatic tumor burden. Furthermore, metastases in treated animals have a less invasive morphology. We show in vitro that CNI-1493 decreases M2-stimulated Ewing Sarcoma tumor cell invasion and extravasation, offering a functional mechanism through which CNI-1493 attenuates metastasis. These data indicate that CNI-1493 may be a safe and effective adjuvant agent for the prevention and treatment of metastatic Ewing Sarcoma.     

Elucidation of the mechanism involved in the regulation of protease production by immobilizedMyxococcus xanthus cells

Summary The mechanism involved in the positive effect of immobilization on protease production byMyxococcus xanthus was investigated. The results have shown that this phenomenon was not related to the difficulty encountered by the potential repressors to diffuse through the gel beads. The positive effect of immobilization on protease synthesis is the result of a different physiological state of the cells due to the stress caused by immobilization.     

Pharmacologic modulation of RNA splicing enhances anti-tumor immunity

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LTR-Retrotransposons in R. exoculata and Other Crustaceans: The Outstanding Success of GalEa-Like Copia Elements

Transposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. They can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. LTR-retrotransposons have been reported in many diverse eukaryote species, describing a ubiquitous distribution. Given their abundance, diversity and their extended ranges in C-values, environment and life styles, crustaceans are a great taxon to investigate the genomic component of adaptation and its possible relationships with TEs. However, crustaceans have been greatly underrepresented in transposable element studies. Using both degenerate PCR and in silico approaches, we have identified 35 Copia and 46 Gypsy families in 15 and 18 crustacean species, respectively. In particular, we characterized several full-length elements from the shrimp Rimicaris exoculata that is listed as a model organism from hydrothermal vents. Phylogenic analyses show that Copia and Gypsy retrotransposons likely present two opposite dynamics within crustaceans. The Gypsy elements appear relatively frequent and diverse whereas Copia are much more homogeneous, as 29 of them belong to the single GalEa clade, and species- or lineage-dependent. Our results also support the hypothesis of the Copia retrotransposon scarcity in metazoans compared to Gypsy elements. In such a context, the GalEa-like elements present an outstanding wide distribution among eukaryotes, from fishes to red algae, and can be even highly predominant within a large taxon, such as Malacostraca. Their distribution among crustaceans suggests a dynamics that follows a “domino days spreading” branching process in which successive amplifications may interact positively.     

Modeling the Biogeography of Fossil Baboons

We use a model of modern baboon socio-ecology to explore the behavioral ecology and biogeography of the extinct Plio-Pleistocene baboons (genera Parapapio, Gorgopithecus, Dinopithecus, and Papio). The model is based on the way climate affects the baboons’ time budgets, and focuses on intersite variability in behavior rather than on species-typical patterns of behavior, as most previous approaches have done. We use climate estimates for individual fossil sites based on matching modern habitats using faunal profiles and estimates of individual species’ body masses given in the literature. The model allows us to examine the minimum and maximum sizes of groups that individual species would have been able to support at particular localities, and hence the biogeography of a species on a continental scale. In doing so, the model allows us to examine which variables are most responsible for limiting a species’ ecological and biogeographic flexibility, and through this to explore a species’ capacity for coping with climate change. Feeding time is identified as the main constraint. In general, large-bodied species would have had more difficulty surviving in as wide a range of habitats as smaller-bodied species, and this may explain the limited geographical distribution of large-bodied baboons such as Gorgopithecus and Dinopithecus.