Reconnaissance des formes de poils de lapin Angora

National audienc

Denombrement automatique de virus Mamestra brassicae par analyse d'images

National audienc

A comparative study of nickel and alumina sintering using spark plasma sintering (SPS)

International audienceNickel and alumina powders with particle sizes of 4.3 mu m and 108 nm, respectively, have been sintered in moulds of different sizes. Only the diameter (inner and/or outer) of moulds has been varied. The dimension modification is responsible for sample microstructure variation because set temperature, heating rate, dwell time and pressure were identical in all experiments. The influence of the die (or sample) dimension on the sample microstructure appears to depend strongly on the electric characteristics of the powder. The present paper is an attempt to correlate the bulk microstructure evolution with the die and sample size and the electrical current distribution within the system

Coral reef fish communities of natural habitats and man-made coastal structures in Bora-Bora (French Polynesia)

Coastal habitats have long been recognised to be nurseries and growing grounds for many marine organisms. Worldwide, coastal hardening and urbanisation are leading to the removal of natural ecosystems. The tropical island of Bora-Bora in the South Pacific has undergone extensive coastal changes, with the construction of seawalls along more than half of its coastline since the 1950s. The daytime and night-time juvenile and adult fish communities were surveyed with multiple temporal replicates on a range of lagoon and coastal habitats on Bora-Bora. Over 47% of all fish on coastal habitats were juveniles. Mangroves, traditionally viewed as nurseries, had a high daytime and night-time abundance of juveniles, but less than 1% of the coastline of Bora-Bora consists of mangroves. The manmade seawalls, which are the most common type of coastal habitat on the island, were associated with lower juvenile densities during the day and promoted the presence of predators. The comparison of coastal and lagoon sites also highlighted contrasting life history strategies depending on coral reef fish species: although many favour coastal habitats as juveniles, others do not undergo ontogenetic shifts and thus other habitats must be considered when designing management plans to protect juvenile fish. Overall, our surveys show the importance of natural coastal zones in the lifecycle of numerous coral reef fish species in the lagoon of Bora-Bora and highlight the potential long-term impacts of coastal hardening on fish communities

Is unpredictable chronic mild stress (UCMS) a reliable model to study depression-induced neuroinflammation?

International audienceUnipolar depression is one of the leading causes of disability. The pathophysiology of depression is poorly understood. Evidence suggests that inflammation is associated with depression. For instance, pro-inflammatory cytokines are found to be elevated in the peripheral blood of depressed subjects. Cytokine immunotherapy itself is known to induce depressive symptoms. While the epidemiological and biochemical relationship between inflammation and depression is strong, little is known about the possible existence of neuroinflammation in depression. The use of animal models of depression such as the Unpredictable Chronic Mild Stress (UCMS) has already contributed to the elucidation of the pathophysiological mechanisms of depression such as decreased neurogenesis and HPA axis alterations. We used this model to explore the association of depressive-like behavior in mice with changes in peripheral pro-inflammatory cytokines IL-1β, TNFα and IL-6 level as well as the neuroinflammation by quantifying CD11b expression in brain areas known to be involved in the pathophysiology of depression. These areas include the cerebral cortex, the nucleus accumbens, the bed nucleus of the stria terminalis, the caudate putamen, the amygdala and the hippocampus. The results indicate that microglial activation is significantly increased in the infralimbic, cingulate and medial orbital cortices, nucleus accumbens, caudate putamen, amygdala and hippocampus of the mouse brain as a function of UCMS, while levels of pro-inflammatory cytokines did not differ among the groups. This finding suggests that neuroinflammation occurs in depression and may be implicated in the subject's behavioral response. They also suggest that UCMS could be a potentially reliable model to study depression-induced neuroinflammation

Roadside sales activities in a South Pacific Island (Bora-Bora) reveal sustainable strategies for local food supply during a pandemic

During the COVID-19 pandemic, the reduced exports and imports as well as the lack of activity due to the interruption in the international tourism economy seriously impacted food security in many Pacific Islands. People often returned to natural resources to provide for themselves, their families, or to generate income. On Bora-Bora Island, the major tourist destination in French Polynesia, roadside sales are widespread. Our study analyses the impact of the COVID-19 pandemic on roadside sales activities through a census of roadside stalls on the five Bora-Bora districts conducted before (January and February 2020), during (from March 2020 to October 2021) and after (from November to December 2021) health-related activity and travel restrictions. Our results showed that the marketing system for local products (fruits, vegetables, cooked meals, and fish) increased in the form of roadside sales during the COVID-19 in two of the five districts of Bora-Bora. Roadside selling would be an alternative system for providing food to the population at Bora-Bora during a global crisis and that could reveal itself sustainable after this pandemic

Isolation and characterization of two canine melanoma cell lines new models for comparative oncology

International audienceBackground: Metastatic melanoma is one of the most aggressive forms of cancer in humans. Among its types, mucosal melanomas represent one of the most highly metastatic and aggressive forms, with a very poor prognosis. Because they are rare in Caucasian individuals, unlike cutaneous melanomas, there has been fewer epidemiological, clinical and genetic evaluation of mucosal melanomas. Moreover, the lack of predictive models fully reproducing the pathogenesis and molecular alterations of mucosal melanoma makes its treatment challenging. Interestingly, dogs are frequently affected by melanomas of the oral cavity that are characterized, as their human counterparts, by focal infiltration, recurrence, and metastasis to regional lymph nodes, lungs and other organs. In dogs, some particular breeds are at high risk, suggesting a specific genetic background and strong genetic drivers. Altogether, the striking homologies in clinical presentation, histopathological features, and overall biology between human and canine mucosal melanomas make dogs invaluable natural models with which to investigate tumor development, including tumor aetiology, and develop tailored treatments.Methods: We developed and characterized two canine oral melanoma cell lines from tumors isolated from dog patients with distinct clinical profiles; with and without lung metastases. The cells were characterized using immunohistochemistry, pharmacology and genetic studies.Results: We have developed and immunohistochemically, genetically, and pharmacologically characterized. Two cell lines (Ocr_OCMM1X and Ocr_OCMM2X) were produced through mouse xenografts originating from two clinically contrasting melanomas of the oral cavity. Their exhaustive characterization showed two distinct biological and genetic profiles that are potentially linked to the stage of malignancy at the time of diagnosis and sample collection of each melanoma case. These cell lines thus constitute relevant tools with which to perform genetic and drug screening analyses for a better understanding of mucosal melanomas in dogs and humans.Conclusions: The aim of this study was to establish and characterize xenograft-derived canine melanoma cell lines with different morphologies, genetic features and pharmacological sensitivities that constitute good predictive models for comparative oncology. These cell lines are relevant tools to advance the use of canine mucosal melanomas as natural models for the benefit of both veterinary and human medicine

Impact of selection regime and introgression on deltamethrin resistance in the arbovirus vector Aedes aegypti – a comparative study between contrasted situations in New Caledonia and French Guiana

International audienceBACKGROUNDPyrethroid insecticides such as deltamethrin have been massively used against Aedes aegypti leading to the spread of resistance alleles worldwide. In an insecticide resistance management context, we evaluated the temporal dynamics of deltamethrin resistance using two distinct populations carrying resistant alleles at different frequencies. Three different scenarios were followed: a continuous selection, a full release of selection, or a repeated introgression with susceptible individuals. The responses of each population to these selection regimes were measured across five generations by bioassays and by monitoring the frequency of knockdown resistance (kdr) mutations and the transcription levels and copy number variations of key detoxification enzymes.RESULTSKnockdown resistance mutations, overexpression and copy number variations of detoxification enzymes as a mechanism of metabolic resistance to deltamethrin was found and maintained under selection across generations. On comparison, the release of insecticide pressure for five generations did not affect resistance levels and resistance marker frequencies. However, introgressing susceptible alleles drastically reduced deltamethrin resistance in only three generations.CONCLUSIONThe present study confirmed that strategies consisting to stop deltamethrin spraying are likely to fail when the frequencies of resistant alleles are too high and the fitness cost associated to resistance is low. In dead-end situations like in French Guiana where alternative insecticides are not available, alternative control strategies may provide a high benefit for vector control, particularly if they favor the introgression of susceptible alleles in natural populations

From Clouds to Young Stellar Objects and back again: the all-in-one view from the Herschel infrared Galactic Plane Survey

From diffuse interstellar cirrus to dense atomic and molecular clouds, from protostellar to post-AGB envelopes, from super-shells to supernovae remnants, the Herschel Hi-GAL survey offer an unprecedented snapshot of all the different phases of the Galactic ISM, its evolution and interactions. I will present early results on a variety of topics including the lifetime of massive pre-stellar phases, the fragmentation and collapse of extended structures, the timeline for massive star formation, dust properties in cirrus and molecular clouds