Addition to the scorpion fauna of the Manaus region (Brazil), with a description of two new species of Tityus from the canopy

Two new species belonging to the genus Tityus C.L. KOCH are described from the region of Manaus, Amazonas State, Brazil. Until now a total of 9 scorpion species have been listed from this region, which is the best known region of Brazilian Amazonia. Both new species were collected from the forest canopy by means of insecticial fogging. Even though other scorpion species have previously been collected in the canopy, we suggest that the new species represent the first known examples of species living exclusively in this environment

Computational Model of the Insect Pheromone Transduction Cascade

A biophysical model of receptor potential generation in the male moth olfactory receptor neuron is presented. It takes into account all pre-effector processes—the translocation of pheromone molecules from air to sensillum lymph, their deactivation and interaction with the receptors, and the G-protein and effector enzyme activation—and focuses on the main post-effector processes. These processes involve the production and degradation of second messengers (IP3 and DAG), the opening and closing of a series of ionic channels (IP3-gated Ca2+ channel, DAG-gated cationic channel, Ca2+-gated Cl− channel, and Ca2+- and voltage-gated K+ channel), and Ca2+ extrusion mechanisms. The whole network is regulated by modulators (protein kinase C and Ca2+-calmodulin) that exert feedback inhibition on the effector and channels. The evolution in time of these linked chemical species and currents and the resulting membrane potentials in response to single pulse stimulation of various intensities were simulated. The unknown parameter values were fitted by comparison to the amplitude and temporal characteristics (rising and falling times) of the experimentally measured receptor potential at various pheromone doses. The model obtained captures the main features of the dose–response curves: the wide dynamic range of six decades with the same amplitudes as the experimental data, the short rising time, and the long falling time. It also reproduces the second messenger kinetics. It suggests that the two main types of depolarizing ionic channels play different roles at low and high pheromone concentrations; the DAG-gated cationic channel plays the major role for depolarization at low concentrations, and the Ca2+-gated Cl− channel plays the major role for depolarization at middle and high concentrations. Several testable predictions are proposed, and future developments are discussed

Merkel cell carcinoma of the head and neck: a single institutional experience

Merkel cell carcinoma (MCC) is a rare cutaneous malignancy occurring mostly in older immunocompromized Caucasian males. A growing incidence of MCC has been reported in epidemiological studies. Treatment of MCC usually consists of surgical excision, pathological lymph node evaluation, and adjuvant radiotherapy. This paper reports the experience of a single tertiary center institution with 17 head and neck Merkel cell carcinoma patients. Median followup for the cohort was 37.5 months. After five years, recurrence-free survival, disease specific survival, and overall survival were 85%, 90%, and 83%, respectively. Our limited data support the use of adjuvant radiotherapy. We also report two cases of MCC located at the vestibule of the nose and two cases of spontaneous regression after diagnostic biopsy. About 40% of our patients were referred to our center for surgical revision and pathological lymph node evaluation. Increased awareness of MCC and an interdisciplinary approach are essential in the management of MCC

Identification of a curative treatment to control cryptosporidiosis

International audienceCryptosporidium parvum is a zoonotic protozoan parasite that causes cryptosporidiosis. It is characterized by infection of the epithelial cells of the small intestines leading to acute watery diarrhea and consequently to dehydration that may lead to death in severe cases. Cryptosporidiosis represents a true one-health threat affecting humans and veterinary health. There is no vaccine and very limited chemotherapy available for humans and animals. Therefore, there is an urgent need for developing efficient curative compounds to control the disease.To do so, two complementary approaches will be used within this PhD project, with two collaborators, M.H. Hakimi (IAB, Grenoble) and C. Hedberg (Umea University) with the support of two funding sources. The first one has the purpose to chemically optimize an initial lead compound using structure activity relationship (SAR) to be used in ruminants as curative treatment against Cryptosporidiosis.We have generated 2 new Cryptosporidium parvum (INRAE) strains harboring fluorescent proteins (GFP/mCherry) and Nluc using the CRISP-cas9 technique. We are using these parasites in vitro and in vivo for precise/fine detection of parasite development. In our in vitro experiments, we compared the last generation of compounds by performing EC50 showing impressive activities in the low picomolar range and presenting low toxicity (MTS assay) leading to a selectivity index close to 106. The lead compound, administered orally, presents strong efficacy in vivo in the GKO mouse model and in newborn lambs, one of the target species of the parasite. Both parasite load and symptoms were severely reduced and no natural resistance observed so far even in the presence of suboptimal dosage. We have now a first highly promising candidate in hand for which we will determine the precise mechanism of action, impact of the treatment on microbiota, and the presence of secondary metabolites within lamb tissues following repeated oral treatments

Identification of a curative treatment to control cryptosporidiosis

International audienceCryptosporidium parvum is a zoonotic protozoan parasite that causes cryptosporidiosis. It is characterized by infection of the epithelial cells of the small intestines leading to acute watery diarrhea and consequently to dehydration that may lead to death in severe cases. Cryptosporidiosis represents a true one-health threat affecting humans and veterinary health. There is no vaccine and very limited chemotherapy available for humans and animals. Therefore, there is an urgent need for developing efficient curative compounds to control the disease.To do so, two complementary approaches will be used within this PhD project, with two collaborators, M.H. Hakimi (IAB, Grenoble) and C. Hedberg (Umea University) with the support of two funding sources. The first one has the purpose to chemically optimize an initial lead compound using structure activity relationship (SAR) to be used in ruminants as curative treatment against Cryptosporidiosis.We have generated 2 new Cryptosporidium parvum (INRAE) strains harboring fluorescent proteins (GFP/mCherry) and Nluc using the CRISP-cas9 technique. We are using these parasites in vitro and in vivo for precise/fine detection of parasite development. In our in vitro experiments, we compared the last generation of compounds by performing EC50 showing impressive activities in the low picomolar range and presenting low toxicity (MTS assay) leading to a selectivity index close to 106. The lead compound, administered orally, presents strong efficacy in vivo in the GKO mouse model and in newborn lambs, one of the target species of the parasite. Both parasite load and symptoms were severely reduced and no natural resistance observed so far even in the presence of suboptimal dosage. We have now a first highly promising candidate in hand for which we will determine the precise mechanism of action, impact of the treatment on microbiota, and the presence of secondary metabolites within lamb tissues following repeated oral treatments

Fast intensity adaptation enhances the encoding of sound in Drosophila

Complex auditory stimuli such as courtship song are sensed by mechanosensory neurons (JONs) in Drosophila antennae. Here the authors report two forms of adaptation in JONs that correct for antennal position (mean) as well as background sound intensity (variance) to maintain sensitivity to natural sensory stimuli