Caenorhabditis elegans muscle Cys-loop receptors as novel targets of terpenoids with potential anthelmintic activity

The anthelmintic treatment of nematode infections remains the pillar of worm control in both human and veterinary medicine. Since control is threatened by the appearance of drug resistant nematodes, there is a need to develop novel compounds, among which phytochemicals constitute potential anthelmintic agents. Caenorhabditis elegans has been pivotal in anthelmintic drug discovery and in revealing mechanisms of drug action and resistance. By using C. elegans, we here revealed the anthelmintic actions of three plant terpenoids -thymol, carvacrol and eugenol- at the behavioral level. Terpenoids produce a rapid paralysis of worms with a potency rank order carvacrol > thymol > eugenol. In addition to their paralyzing activity, they also inhibit egg hatching, which would, in turn, lead to a broader anthelmintic spectrum of activity. To identify drug targets, we performed an in vivo screening of selected strains carrying mutations in receptors involved in worm locomotion for determining resistance to the paralyzing effect of terpenoids. The assays revealed that two Cys-loop receptors with key roles in worm locomotion -Levamisole sensitive nicotinic receptor (L-AChR) and GABA(A) (UNC-49) receptor- are involved in the paralyzing effects of terpenoids. To decipher the mechanism by which terpenoids affect these receptors, we performed electrophysiological studies using a primary culture of C. elegans L1 muscle cells. Whole cell recordings from L1 cells demonstrated that terpenoids decrease macroscopic responses of L-AChR and UNC-49 receptor to their endogenous agonists, thus acting as inhibitors. Single-channel recordings from L-AChR revealed that terpenoids decrease the frequency of opening events, probably by acting as negative allosteric modulators. The fact that terpenoids act at different receptors may have important advantages regarding efficacy and development of resistance. Thus, our findings give support to the use of terpenoids as either an alternative or a complementary anthelmintic strategy to overcome the ever-increasing resistance of parasites to classical anthelmintic drugs.Fil: Hernando, Guillermina Silvana. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Turani, Ornella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Bouzat, Cecilia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Sistema de classificació automàtica per a continguts audiovisuals mitjançant Low-Level Descriptors d'MPEG-7

Es poden definir unes fites: - Construir un discriminador entre veu, música, silenci, i soroll. - Construir un discriminador de gènere. - Construir un discriminador de diferents locutors. - Construcció d'un segmentador automàtic dels diferents esdeveniments sonors. Per una altra part, l'objectiu acadèmic i de recerca serà estudiar si es pot construir un classificador eficient mitjançant únicament les eines que proporciona l'estàndard MPEG-7

Caenorhabditis elegans neuromuscular junction: GABA receptors and ivermectin action

The prevalence of human and animal helminth infections remains staggeringly high, thus urging the need for concerted efforts towards this area of research. GABA receptors, encoded by the unc-49 gene, mediate body muscle inhibition in Caenorhabditis elegans and parasitic nematodes and are targets of anthelmintic drugs. Thus, the characterization of nematode GABA receptors provides a foundation for rational anti-parasitic drug design. We therefore explored UNC-49 channels from C. elegans muscle cultured cells of the first larval stage at the electrophysiological and behavioral levels. Whole-cell recordings reveal that GABA, muscimol and the anthelmintic piperazine elicit macroscopic currents from UNC-49 receptors that decay in their sustained presence, indicating full desensitization. Single-channel recordings show that all drugs elicit openings of ,2.5 pA (+100 mV), which appear either as brief isolated events or in short bursts. The comparison of the lowest concentration required for detectable channel opening, the frequency of openings and the amplitude of macroscopic currents suggest that piperazine is the least efficacious of the three drugs. Macroscopic and single-channel GABA-activated currents are profoundly and apparently irreversibly inhibited by ivermectin. To gain further insight into ivermectin action at C. elegans muscle, we analyzed its effect on single-channel activity of the levamisol-sensitive nicotinic receptor (L-AChR), the excitatory receptor involved in neuromuscular transmission. Ivermectin produces a profound inhibition of the frequency of channel opening without significant changes in channel properties. By revealing that ivermectin inhibits C. elegans muscle GABA and L-AChR receptors, our study adds two receptors to the already known ivermectin targets, thus contributing to the elucidation of its pleiotropic effects. Behavioral assays in worms show that ivermectin potentiates piperazine-induced paralysis, thus suggesting that their combination is a good strategy to overcome the increasing resistance of parasites, an issue of global concern for human and animal healthFil: Hernando, Guillermina Silvana. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET Bahía Blanca. Instituto de Investigaciones Bioquímicas Bahía Blanca (i); ArgentinaFil: Bouzat, Cecilia Beatriz. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET Bahía Blanca. Instituto de Investigaciones Bioquímicas Bahía Blanca (i); Argentin

Optimization of a portable NIR device for the optical supervision of milk coagulation process

The coagulation of milk is the fundamental process in cheese-making, which is based on a gel formation as consequence of physicochemical changes taking place in the casein micelles. Monitoring the whole process of milk curd formation is a dedicated process for dairy researchers and cheese companies. In addition to advances in composition-based applications by means of NIR spectroscopy, researchers are pursuing dynamic applications that show promise especially with regard to tracking a sample in situ during processing The objective of this work is to propose an original portable NIR equipment to supervise the milk coagulation process. The experiments have been carried out on sheep and goat milk, by immersion of the probe directly in the liquid and acquiring spectrum each 1 minute during the 30 minutes of coagulation process. The increasing values of transflected light registered allow identifying, based on PCA analysis, the different kinetics that occur along the gel formation and the time to reach the optimal gel firmness to cut the cur

Notes on the postcranial osteology of the sand lizard Liolaemus azarai (Squamata: Liolaemidae)

We examined skeletons of seven adult and juvenile specimens of Liolaemus azarai that were cleared and double-stained. The states of twenty three postcranial skeleton characters were described and compared with others Liolaemus species. Our findings complement the current knowledge about the osteological variation in Liolaemus and the character states may include in a data matrix to future phylogenetic studies.Fil: Gonzalez Marin, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Hernando, Alejandra Beatriz. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentin

Nuevas técnicas para la mitigación de clutter de aerogeneradores en radares meteorológicos

La instalación de fuentes productoras de energía eólica está ganando mucha importancia actualmente debido a sus muchas ventajas. Países de todo el mundo promueven la construcción de nuevos parques eólicos para producir energía eléctrica en un intento de luchar contra el cambio climático y los crecientes costes del petróleo. Sin embargo, los aerogeneradores pueden generar señales indeseadas que interfieren en el correcto funcionamiento de muchos sistemas de comunicaciones y también en sistemas de radar. En particular, esto es un grave problema para los radares meteorológicos. En su caso, los aerogeneradores eólicos son vistos como clutter, dado que tienen una fuerte influencia en los productos meteorológicos tales como la estimación de la intensidad de lluvia o la velocidad del viento. En los últimos años se han presentado diversos estudios del impacto de los aerogeneradores sobre radares y otros sistemas de comunicaciones. Además, se han propuesto algunas técnicas que permitirían minimizar su impacto. En esta Tesis Doctoral se presenta la investigación realizada sobre el clutter producido por aerogeneradores en radares meteorológicos. Se han revisado cuidadosamente los efectos de los parques eólicos en los productos radar de reflectividad, velocidad y anchura espectral. También se han estudiado en profundidad los mecanismos físicos que producen este tipo de clutter. Para ello se han utilizado simulaciones teóricas que permiten modelar tanto el clutter producido por aerogeneradores como las señales que producen los fenómenos meteorológicos como la precipitación de lluvia. Dichas simulaciones se han validado con datos experimentales provenientes de los radares de la Agencia Estatal de Meteorología (AEMET). Se realizaron diversos experimentos grabando datos radar de las zonas contaminadas por parques eólicos en diferentes condiciones meteorológicas. Se utilizaron dos tipos de exploración radar. El primer modo, estático, permite analizar la información del clutter en función del tiempo, ya que se mantiene la antena del radar fija apuntando al parque eólico. El segundo modo, operativo, permite obtener la información del clutter que recogería el radar con un funcionamiento de vigilancia normal. También se han desarrollado algoritmos de mitigación que permiten minimizar el efecto de este tipo de clutter sobre los productos meteorológicos. Dichos algoritmos se han probado sobre datos reales de clutter y señal de precipitación para los dos modos de grabación utilizados. Los resultados muestran un buen comportamiento de los algoritmos y un buen rendimiento en términos de reflectividad y velocidad resultantes en unos casos y calidad de imágenes radar en otros. Abstract The use of wind energy is gaining importance because of its many advantages. Nations worldwide are promoting the installation of wind farms to produce electricity in an attempt to tackle climate change and increasing oil costs. However, wind turbines can generate undesired signals that disturb the performance of radiocommunication systems as well as radar systems. In particular, this is an issue for weather radar networks. Weather radars see wind turbines as clutter, since they have a strong influence on meteorological outputs such as the estimation of rain intensity or wind velocity. Over the last few years several studies about the impact of wind turbines on radars and other radiocommunications systems have been presented. A few techniques have appeared, too, trying to minimize the impacts of wind turbine clutter on radars and radiocommunications systems. A research about wind turbine clutter on meteorological radars is presented in this Thesis. The effects of wind farms on the weather radar products, reflectivity, velocity and spectrum width, have been carefully revised. The physical mechanisms that produce this kind of clutter are also thoroughly studied in this Thesis In order to do so, theoretical simulations that allow modeling not only the wind turbine clutter but also the weather phenomena such us rain, are used. These simulations have been validated using experimental data from the radars of the Spanish Meteorological Agency (AEMET). Several experiments gathering weather radar data from contaminated areas were conducted. Two different exploration modes were used. First, a static mode allows the analysis of the information about the clutter as a function of time, since the radar antenna is fixed pointing the wind farm while gathering the data. Second, the scanning mode allows the analysis of the information the operating radar would gather in a regular surveillance mode. In addition, mitigation algorithms allowing the minimization of the effect of wind turbine clutter on meteorological radar products were designed. These algorithms have been tested over real clutter and weather signal radar data for the two operation modes commented before. The results exhibit a good behavior of the algorithms and an acceptable performance in terms of resulting values of reflectivity and velocity in some cases and image quality in others

Caries: análisis de la relación entre los estadios clínicos y radiográficos. Propuesta de una nueva clasificación

La caries dental continúa siendo una de las enfermedades con mayor prevalencia a nivel mundial. Su diagnóstico se realiza principalmente mediante exploración visual y radiográfica. Debido a la variedad en formas clínicas, lugares de presentación, diagnóstico, actividad y terapéutica, se hace necesario clasificar las caries para ordenar la enfermedad y lesión en base a unos criterios.En la actualidad la clasificación que siguen utilizando los profesionales para la comunicación y el registro de la lesión es la de Black. Debido a que la caries es una enfermedad dinámica y no estática, a lo largo de la historia han surgido diversas clasificaciones como es la de Sitio/Estadío para su registro. Aunque es una clasificación sencilla, adolece de incorporar detalladamente el criterio radiográfico por lo que creemos que es conveniente para su uso clínico y docente.Por ello decidimos estudiar la fiabilidad de la clasificación de Mejàre modificada para su incorporación a la clasificación de Sitio/Estadío, así como analizar y comprender las relaciones que se establecen entre los estadíos clínicos y radiográficos para complementar dicha clasificación o confeccionar una nueva para su uso clínico así como docente..

The nematode serotonin-gated chloride channel MOD-1: A novel target for anthelmintic therapy

Anthelmintics are used to treat human and veterinary parasitic diseases and to reduce crop and livestock production loss associated with parasitosis. The free-living nematode Caenorhabditis elegans, a model system for anthelmintic drug discovery, has a serotonin (5-HT)-gated chloride channel, MOD-1, which belongs to the Cys-loop receptor family and modulates locomotory and behavioral functions. Since MOD-1 is unique to nematodes, it is emerging as an attractive anthelmintic drug target, but details of MOD-1 function are unclear. Here, we revealed novel aspects of MOD-1 function from the molecular level to the organism level and identified compounds targeting this receptor, which may provide new directions for anthelmintic drug discovery. We used whole-cell current recordings from heterologously expressed MOD-1 to show that tryptamine (Tryp), a weak partial agonist of vertebrate serotonin type 3 (5-HT3) receptors, efficaciously activates MOD-1. A screen for modulators revealed that GABAergic ligands piperazine (PZE) and muscimol reduce 5-HT-elicited currents, thus identifying novel MOD-1 allosteric inhibitors. Next, we performed locomotor activity assays, and we found 5-HT and Tryp rapidly decrease worm motility, which is reversible only at low 5-HT concentrations. Mutants lacking MOD-1 are partially resistant to both drugs, demonstrating its role in locomotion. Acting as an antagonist of MOD-1, we showed PZE reduces the locomotor effects of exogenous 5-HT. Therefore, Tryp- and PZE-derived compounds, acting at MOD-1 through different molecular mechanisms, emerge as promising anthelmintic agents. This study enhances our knowledge of the function and drug selectivity of Cys-loop receptors and postulates MOD-1 as a potential target for anthelmintic therapy.Fil: Rodriguez Araujo, Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Hernando, Guillermina Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Corradi, Jeremias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Bouzat, Cecilia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin