Seasonal and annual variation of carbon exchange in an evergreen Mediterranean forest in southern France

We present 9 years of eddy covariance measurements made over an evergreen Mediterranean forest in southern France. The goal of this study was to quantify the different components of the carbon (C) cycle, gross primary production (GPP) and ecosystem respiration (R-eco), and to assess the effects of climatic variables on these fluxes and on the net ecosystem exchange of carbon dioxide. The Puechabon forest acted as a net C sink of -254 g C m(-2) yr(-1), with a GPP of 1275 g C m(-2) yr(-1) and a R-eco of 1021 g C m(-2) yr(-1). On average, 83% of the net annual C sink occurred between March and June. The effects of exceptional events such the insect-induced partial canopy defoliation that occurred in spring 2005, and the spring droughts of 2005 and 2006 are discussed. A high interannual variability of ecosystem C fluxes during summer and autumn was observed but the resulting effect on the annual net C budget was moderate. Increased severity and/or duration of summer drought under climate change do not appear to have the potential to negatively impact the average C budget of this ecosystem. On the contrary, factors affecting ecosystem functioning (drought and/or defoliation) during March-June period may reduce dramatically the annual C balance of evergreen Mediterranean forests

Estimation de l’âge de la nymphe de Calliphora vicina, Calliphora vomitoria et Lucilia sericata par l’observation de caractères morphologiques externes (Diptera, Calliphoridae)

Estimating the age of the nymph of Calliphora vicina, C. vomitoria and Lucilia sericata by observing external morphological characters (Diptera, Calliphoridae). The authors propose to sequence the evolution of the nympha based upon external morphological characters observation thorough the pupation with aim to estimate the age the specimen. The study was carried out during the metamorphosis of three species of Diptera Calliphoridae of forensic importance : Calliphora vicina Robineau-Desvoidy, 1830, C. vomitoria (Linné, 1758) and Lucilia sericata (Meigen, 1826). Thus, a simple observation in transparency shows five main sequences identified in the pupal development for the two species of Calliphora and four sequences for Lucilia sericata. After dissection, the results are more accurate, with nine sequences for all the Calliphora studied, and seven for L. sericata. Results are expressed as a percentage of the total duration of pupal stage development.Dans la perspective d’une utilisation en entomologie forensique, il est proposé de séquencer l’évolution de la nymphe de trois espèces de Diptères Calliphoridae : Calliphora vicina Robineau-Desvoidy, 1830, C. vomitoria (Linné, 1758) et Lucilia sericata (Meigen, 1826) sur la base de caractères morphologiques externes afin d’en estimer l’âge lors de leur phase de métamorphose. Ainsi, une observation simple par transparence met en évidence cinq séquences majeures identifiables dans le développement nymphal des deux espèces de Calliphora et quatre pour Lucilia sericata. Après dissection, les résultats sont plus précis. Pour les Calliphora étudiées, neuf séquences sont individualisées, sept pour L. sericata. Ce séquençage est exprimé en pourcentage de la durée totale du développement nymphal.Pasquerault Thierry, Cervantes Laetitia, Dourel Laurent, Vincent Benoît, Gaudry Emmanuel, Rocheteau Christophe. Estimation de l’âge de la nymphe de Calliphora vicina, Calliphora vomitoria et Lucilia sericata par l’observation de caractères morphologiques externes (Diptera, Calliphoridae). In: Bulletin de la Société entomologique de France, volume 118 (4),2013. pp. 527-537

Estimation de l’âge de la nymphe de Calliphora vicina, Calliphora vomitoria et Lucilia sericata par l’observation de caractères morphologiques externes (Diptera, Calliphoridae)

Estimating the age of the nymph of Calliphora vicina, C. vomitoria and Lucilia sericata by observing external morphological characters (Diptera, Calliphoridae). The authors propose to sequence the evolution of the nympha based upon external morphological characters observation thorough the pupation with aim to estimate the age the specimen. The study was carried out during the metamorphosis of three species of Diptera Calliphoridae of forensic importance : Calliphora vicina Robineau-Desvoidy, 1830, C. vomitoria (Linné, 1758) and Lucilia sericata (Meigen, 1826). Thus, a simple observation in transparency shows five main sequences identified in the pupal development for the two species of Calliphora and four sequences for Lucilia sericata. After dissection, the results are more accurate, with nine sequences for all the Calliphora studied, and seven for L. sericata. Results are expressed as a percentage of the total duration of pupal stage development.Dans la perspective d’une utilisation en entomologie forensique, il est proposé de séquencer l’évolution de la nymphe de trois espèces de Diptères Calliphoridae : Calliphora vicina Robineau-Desvoidy, 1830, C. vomitoria (Linné, 1758) et Lucilia sericata (Meigen, 1826) sur la base de caractères morphologiques externes afin d’en estimer l’âge lors de leur phase de métamorphose. Ainsi, une observation simple par transparence met en évidence cinq séquences majeures identifiables dans le développement nymphal des deux espèces de Calliphora et quatre pour Lucilia sericata. Après dissection, les résultats sont plus précis. Pour les Calliphora étudiées, neuf séquences sont individualisées, sept pour L. sericata. Ce séquençage est exprimé en pourcentage de la durée totale du développement nymphal.Pasquerault Thierry, Cervantes Laetitia, Dourel Laurent, Vincent Benoît, Gaudry Emmanuel, Rocheteau Christophe. Estimation de l’âge de la nymphe de Calliphora vicina, Calliphora vomitoria et Lucilia sericata par l’observation de caractères morphologiques externes (Diptera, Calliphoridae). In: Bulletin de la Société entomologique de France, volume 118 (4),2013. pp. 527-537

Seasonal Variation in the Home Ranges of Black Curassow, Crax alector , in French Guiana

Cracidae is the most threatened avian family in the Neotropics, mainly because of habitat destruction, heavy hunting pressure and poaching. In French Guiana, Black Curassows are heavily hunted, although basic knowledge of the ecological and demographical traits of the species remains limited. Such a gap prevents any attempt to assess the impact of hunting and to help stakeholders to develop proposals ensuring hunting sustainability. The spatial relationship between animals and their habitat is important for conservation management, being related to population densities through complex patterns. Here, we report on a radio-tracking study of Black Curassows in tropical primary rainforest, in Nouragues National Reserve, French Guiana. The aims of the study were to estimate home range size and its variation across seasons, and to quantify movement patterns of the birds. We captured and fitted VHF tags to four adults, and tracked them for 10 to 21.5 months. Daily movements were recorded, and home ranges estimated using the Kernel Density method, for two consecutive wet seasons and one dry season. Using 95% and 50% Kernel densities, the average annual home range and core area were 96.3± 32.6 ha (SE) and 22.8 ± 2.8 ha respectively. Home ranges appeared spatially stable over the two years, and overlapped between neighbouring groups. During the dry season, Black Curassows did not migrate but tended to enlarge their home range, with greater daily movements and higher home range overlap. Although additional data are still needed, our results can help to improve the knowledge and management of this poorly studied species

Intracellular activity and in vivo efficacy in a mouse model of septic arthritis of the novel pseudopeptide Pep16 against Staphylococcus aureus clinical isolates

International audienceObjectives - Assessing the therapeutic potential of a novel antimicrobial pseudopeptide, Pep16, both and for the treatment of septic arthritis caused by . Methods - Seven clinical isolates of (two MRSA and five MSSA) were studied. MICs of Pep16 and comparators (vancomycin, teicoplanin, daptomycin and levofloxacin) were determined through the broth microdilution method. The intracellular activity of Pep16 and levofloxacin was assessed in two models of infection using non-professional (osteoblasts MG-63) or professional (macrophages THP-1) phagocytic cells. A mouse model of septic arthritis was used to evaluate the efficacy of Pep16 and vancomycin. A preliminary pharmacokinetic (PK) analysis was performed by measuring plasma concentrations using LC-MS/MS following a single subcutaneous injection of Pep16 (10 mg/kg). Results - MICs of Pep16 were consistently at 8 mg/L for all clinical isolates of (2- to 32-fold higher to those of comparators) while MBC/MIC ratios confirmed its bactericidal activity. Both Pep16 and levofloxacin (when used at 2 × MIC) significantly reduced the bacterial load of all tested isolates (two MSSA and two MRSA) within both osteoblasts and macrophages. In MSSA-infected mice, Pep16 demonstrated a significant (∼10-fold) reduction on bacterial loads in knee joints. PK analysis following a single subcutaneous administration of Pep16 revealed a gradual increase in plasma concentrations, reaching a peak of 5.6 mg/L at 12 h. Conclusions - Pep16 is a promising option for the treatment of septic arthritis due to , particularly owing to its robust intracellular activity

Synergistic Activity of Pep16, a Promising New Antibacterial Pseudopeptide against Multidrug-Resistant Organisms, in Combination with Colistin against Multidrug-Resistant Escherichia coli, In Vitro and in a Murine Peritonitis Model

International audienceColistin is a drug of last resort to treat extreme drug-resistant Enterobacterales, but is limited by dose-dependent toxicity and the emergence of resistance. A recently developed antimicrobial pseudopeptide, Pep16, which acts on the cell membrane, may be synergistic with colistin and limit the emergence of resistance. We investigated Pep16 activity against Escherichia coli with varying susceptibility to colistin, in vitro and in a murine peritonitis model. Two isogenic derivatives of E. coli CFT073 (susceptible and resistant to colistin) and 2 clinical isolates (susceptible (B119) and resistant to colistin (Af31)) were used. Pep16 activity, alone and in combination with colistin, was determined in vitro (checkerboard experiments, time-kill curves, and flow cytometry to investigate membrane permeability). Toxicity and pharmacokinetic analyses of subcutaneous Pep16 were performed in mice, followed by the investigation of 10 mg/kg Pep16 + 10 mg/kg colistin (mimicking human concentrations) in a murine peritonitis model. Pep16 alone was inactive (MICs = 32-64 mg/L; no bactericidal effect). A concentration-dependent bactericidal synergy of Pep16 with colistin was evidenced on all strains, confirmed by flow cytometry. In vivo, Pep16 alone was ineffective. When Pep16 and colistin were combined, a significant decrease in bacterial counts in the spleen was evidenced, and the combination prevented the emergence of colistin-resistant mutants, compared to colistin alone. Pep16 synergizes with colistin in vitro, and the combination is more effective than colistin alone in a murine peritonitis by reducing bacterial counts and the emergence of resistance. Pep16 may optimize colistin use, by decreasing the doses needed, while limiting the emergence of colistin-resistant mutants

Synergistic Activity of Pep16, a Promising New Antibacterial Pseudopeptide against Multidrug-Resistant Organisms, in Combination with Colistin against Multidrug-Resistant <i>Escherichia coli</i>, In Vitro and in a Murine Peritonitis Model

Colistin is a drug of last resort to treat extreme drug-resistant Enterobacterales, but is limited by dose-dependent toxicity and the emergence of resistance. A recently developed antimicrobial pseudopeptide, Pep16, which acts on the cell membrane, may be synergistic with colistin and limit the emergence of resistance. We investigated Pep16 activity against Escherichia coli with varying susceptibility to colistin, in vitro and in a murine peritonitis model. Two isogenic derivatives of E. coli CFT073 (susceptible and resistant to colistin) and 2 clinical isolates (susceptible (B119) and resistant to colistin (Af31)) were used. Pep16 activity, alone and in combination with colistin, was determined in vitro (checkerboard experiments, time–kill curves, and flow cytometry to investigate membrane permeability). Toxicity and pharmacokinetic analyses of subcutaneous Pep16 were performed in mice, followed by the investigation of 10 mg/kg Pep16 + 10 mg/kg colistin (mimicking human concentrations) in a murine peritonitis model. Pep16 alone was inactive (MICs = 32–64 mg/L; no bactericidal effect). A concentration-dependent bactericidal synergy of Pep16 with colistin was evidenced on all strains, confirmed by flow cytometry. In vivo, Pep16 alone was ineffective. When Pep16 and colistin were combined, a significant decrease in bacterial counts in the spleen was evidenced, and the combination prevented the emergence of colistin-resistant mutants, compared to colistin alone. Pep16 synergizes with colistin in vitro, and the combination is more effective than colistin alone in a murine peritonitis by reducing bacterial counts and the emergence of resistance. Pep16 may optimize colistin use, by decreasing the doses needed, while limiting the emergence of colistin-resistant mutants

Data from: Habitat specialization predicts genetic response to fragmentation in tropical birds

Habitat fragmentation is one of the most severe threats to biodiversity as it may lead to changes in population genetic structure, with ultimate modifications of species evolutionary potential and local extinctions. Nonetheless, fragmentation does not equally affect all species and identifying which ecological traits are related to species sensitivity to habitat fragmentation could help prioritization of conservation efforts. Despite the theoretical link between species ecology and extinction proneness, comparative studies explicitly testing the hypothesis that particular ecological traits underlies species-specific population structure are rare. Here, we used a comparative approach on eight bird species, co-occurring across the same fragmented landscape. For each species, we quantified relative levels of forest specialization and genetic differentiation among populations. To test the link between forest specialization and susceptibility to forest fragmentation, we assessed species responses to fragmentation by comparing levels of genetic differentiation between continuous and fragmented forest landscapes. Our results revealed a significant and substantial population structure at a very small spatial scale for mobile organisms such as birds. More importantly, we found that specialist species are more affected by forest fragmentation than generalist ones. Finally, our results suggest that even a simple habitat specialization index can be a satisfying predictor of genetic and demographic consequences of habitat fragmentation, providing a reliable practical and quantitative tool for conservation biology

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