Pheromonal modulation as a drive for behavioral plasticity in two insects: honey bees and ants

Les phéromones sont des substances chimiques relâchées dans l'environnement par un individu qui déclenchent des comportements stéréotypés et/ou des processus physiologiques chez des individus de la même espèce. Cependant, une nouvelle hypothèse suggère que les phéromones non seulement suscitent des réponses innées mais contribuent également à la plasticité comportementale en agissant en "modulateurs" de phénomènes cognitifs. Nous avons étudié l'effet modulateur des phéromones sur les réponses réflexes, la prise de décision, et l'apprentissage chez trois espèces d'insectes qui sont des modèles emblématiques en recherche fondamentale et appliquée : l'abeille Apis mellifera, et les fourmis Camponotus aethiops and Linepithema humile. Dans une première étude, nous avons trouvé qu'une phéromone appétitive diminuait la sensibilité aversive, tandis qu'une phéromone d'alarme augmentait la sensibilité aversive chez l'abeille. Chez L. humile, une phéromone de piste synthétique augmentait la sensibilité au sucre et le temps de nourrissage. Globalement, nos résultats démontrent que certaines phéromones modulent la prépondérance des stimuli aversif et appétitif selon leur valence. De cette manière, elles affecteraient la motivation à s'engager dans des réponses aversives ou appétitives, agissant ainsi comme modulateurs de la plasticité comportementale. Nous avons ensuite déterminé l'effet d'une phéromone d'alarme (l'acide formique) sur la prise de décision et les systèmes de reconnaissance dans le cadre de la discrimination de congénères chez des fourmis charpentières. Nous avons trouvé que la phéromone d'alarme améliorait la discrimination en augmentant l'agressivité envers les non congénères et en la diminuant envers les congénères en même temps. Ces résultats remettent en question le modèle établi de reconnaissance de congénères. Nous proposons donc une version révisée de ce modèle. Enfin, nous avons teste l'effet de l'acide formique sur l'apprentissage et la généralisation. L'acide formique augmentait la discrimination en conditionnement différentiel olfactif aversif. En conditionnement différentiel olfactif appétitif, l'acide formique modulait les dynamiques d'acquisition et la perception de la similarité des odeurs. Nous suggérons que les phéromones affectent la perception des odeurs conditionnées et des renforcements selon la nature des odeurs et leurs valeurs intrinsèques pour l'individu, ainsi que la valence des renforcements. Cette thèse présente les premières analyses intégrées de la modulation phéromonale chez deux taxa : les abeilles et les fourmis. Les résultats présentés nous permettent de comprendre une partie des modes d'action des phéromones et ouvrent la voie à de futures études afin de comprendre les mécanismes qui sous-tendent l'effet modulateur des phéromones.Pheromones are chemical substances released into the environment by an individual, which trigger stereotyped behaviors and/or physiological processes in individuals of the same species. Yet, a novel hypothesis has suggested that pheromones not only elicit innate responses but also contribute to behavioral plasticity by acting as "modulators" of cognitive phenomena. We studied the modulator effect of pheromones on reflex responses, decision making and learning in three insect species that are emblematic models for fundamental and applied research: the honeybee Apis mellifera, and the ants Camponotus aethiops and Linepithema humile. In the first study, we found that an appetitive pheromone decreased aversive responsiveness, while an alarm pheromone increased aversive responsiveness in honey bees. In L. humile, a synthetic trail pheromone increased sucrose responsiveness and feeding time. Overall, our results demonstrate that certain pheromones modulate the salience of aversive and appetitive stimuli according to their valence. In this way, they would affect the motivation to engage in aversive or appetitive responses, thus acting as modulators of behavioral plasticity. We then determined the effect of an alarm pheromone (formic acid) on decision making and recognition systems in the frame of nestmate discrimination in carpenter ants. We found that the alarm pheromone improved discrimination by increasing aggressiveness towards non-nestmates and decreasing aggressiveness towards nestmates at the same time. These results challenge the established model of nestmate recognition. We therefore propose a revised version of this model. Eventually, we tested the effect of formic acid on learning and generalization. Formic acid increased discrimination in aversive olfactory differential conditioning. In appetitive olfactory differential conditioning, formic acid modulated the acquisition dynamics and perceived odor similarity. We suggest that pheromones affect the perception of conditioned odors and reinforcements depending on the nature of the odorants and their intrinsic values for the individual, as well as the valence of the reinforcements. This thesis presents the first integrated analyses of pheromone modulation in two insect taxa: honey bees and ants. The presented results allow us to understand some modes of action of pheromones and pave the way for future studies to understand the underlying mechanisms of this modulator effect of pheromones

δ 15N measurement of organic and inorganic substances by EA-IRMS: a speciation-dependent procedure

Little attention has been paid so far to the influence of the chemical nature of the substance when measuring δ 15N by elemental analysis (EA)-isotope ratio mass spectrometry (IRMS). Although the bulk nitrogen isotope analysis of organic material is not to be questioned, literature from different disciplines using IRMS provides hints that the quantitative conversion of nitrate into nitrogen presents difficulties. We observed abnormal series of δ 15N values of laboratory standards and nitrates. These unexpected results were shown to be related to the tailing of the nitrogen peak of nitrate-containing compounds. A series of experiments were set up to investigate the cause of this phenomenon, using ammonium nitrate (NH4NO3) and potassium nitrate (KNO3) samples, two organic laboratory standards as well as the international secondary reference materials IAEA-N1, IAEA-N2—two ammonium sulphates [(NH4)2SO4]—and IAEA-NO-3, a potassium nitrate. In experiment 1, we used graphite and vanadium pentoxide (V2O5) as additives to observe if they could enhance the decomposition (combustion) of nitrates. In experiment 2, we tested another elemental analyser configuration including an additional section of reduced copper in order to see whether or not the tailing could originate from an incomplete reduction process. Finally, we modified several parameters of the method and observed their influence on the peak shape, δ 15N value and nitrogen content in weight percent of nitrogen of the target substances. We found the best results using mere thermal decomposition in helium, under exclusion of any oxygen. We show that the analytical procedure used for organic samples should not be used for nitrates because of their different chemical nature. We present the best performance given one set of sample introduction parameters for the analysis of nitrates, as well as for the ammonium sulphate IAEA-N1 and IAEA-N2 reference materials. We discuss these results considering the thermochemistry of the substances and the analytical technique itself. The results emphasise the difference in chemical nature of inorganic and organic samples, which necessarily involves distinct thermochemistry when analysed by EA-IRMS. Therefore, they should not be processed using the same analytical procedure. This clearly impacts on the way international secondary reference materials should be used for the calibration of organic laboratory standards. Figure Control chart of the δ 15N value of IAEA-N1, IAEA-NO-3 and NH4NO3 analysed a) with oxygen injection (analytical cycle 70 s, oxygen for 60 s, sample start and stop at 18 s/20 s), b) with oxygen injection (analytical cycle 70 s, oxygen for 60 s, sample start and stop at 0 s/2 s and 5 s/7 s), c) without oxygen injection (analytical cycle 70 s, sample start and stop at 18 s/20 s

Harmonic radar tracking reveals that honeybee drones navigate between multiple aerial leks

Male honeybees (drones) are thought to congregate in large numbers in particular “drone congregation areas” to mate. We used harmonic radar to record the flight paths of individual drones and found that drones favored certain locations within the landscape which were stable over two years. Drones often visit multiple potential lekking sites within a single flight and take shared flight paths between them. Flights between such sites are relatively straight and begin as early as the drone's second flight, indicating familiarity with the sites acquired during initial learning flights. Arriving at congregation areas, drones display convoluted, looping flight patterns. We found a correlation between a drone's distance from the center of each area and its acceleration toward the center, a signature of collective behavior leading to congregation in these areas. Our study reveals the behavior of individual drones as they navigate between and within multiple aerial leks

Incidência de microrganismos multirresistentes em lesões de pele de pacientes hospitalizados / Incidence of multidrug-resistant microorganisms in skin lesions of hospitalized patients

As infecções de pele são comuns devido à microbiota natural desse órgão e a vasta veiculação de microrganismos patogênicos e resistentes a antimicrobianos nos ambientes hospitalares. Assim, o objetivo deste trabalho foi verificar a incidência de microrganismos resistentes em diferentes lesões de pacientes hospitalizados em um hospital de São Miguel do Oeste– SC. Foram realizadas 39 coletas em lesões de pacientes hospitalizados no período de julho de 2018 à fevereiro de 2020. As amostras foram coletadas com swabs umedecidos e posteriormente semeadas em meios de cultura para isolamento dos microrganismos. Após a identificação os microrganismos foram submetidos ao teste de suscetibilidade aos antimicrobianos. Foram isoladas 41 cepas de bactérias Gram positivas (Staphylococcus aureus, Staphylococcus coagulase negativa, Corynebacterium sp. e Bacillus sp.) e 37 Gram negativas (Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterobacter aerogenes, Enterobacter sp., Klebsiella pneumoniae, Citrobacter koseri, Stenotrophomonas maltophilia, Burkholderia cepacia e Yersinia sp.). O perfil de suscetibilidade demonstrou que os microrganismos Gram positivos apresentaram sensibilidade principalmente para os antibióticos Nitrofurantoína e Tetraciclina, e resistência para Penicilina e Oxacilina. Já os microrganismos Gram negativos apresentaram sensibilidade principalmente para os antibióticos Imipenem e Amicacina, e resistência para Ampicilina e Nitrofurantoína. Este estudo representa a importância da antibioticoterapia adequada e o uso racional destes medicamentos em internações hospitalares para com isso, evitar o desenvolvimento de resistência por parte dos microrganismos às drogas antibióticas e consequentemente a piora clínica do paciente

The importance of RT-qPCR primer design for the detection of siRNA-mediated mRNA silencing

<p>Abstract</p> <p>Background</p> <p>The use of RNAi to analyse gene function <it>in vitro </it>is now widely applied in biological research. However, several difficulties are associated with its use <it>in vivo</it>, mainly relating to inefficient delivery and non-specific effects of short RNA duplexes in animal models. The latter can lead to false positive results when real-time RT-qPCR alone is used to measure target mRNA knockdown.</p> <p>Findings</p> <p>We observed that detection of an apparent siRNA-mediated knockdown <it>in vivo </it>was dependent on the primers used for real-time RT-qPCR measurement of the target mRNA. Two siRNAs specific for <it>RRM1 </it>with equivalent activity <it>in vitro </it>were administered to A549 xenografts via intratumoural injection. In each case, apparent knockdown of <it>RRM1 </it>mRNA was observed only when the primer pair used in RT-qPCR flanked the siRNA cleavage site. This false-positive result was found to result from co-purified siRNA interfering with both reverse transcription and qPCR.</p> <p>Conclusions</p> <p>Our data suggest that using primers flanking the siRNA-mediated cleavage site in RT-qPCR-based measurements of mRNA knockdown <it>in vivo </it>can lead to false positive results. This is particularly relevant where high concentrations of siRNA are introduced, particularly via intratumoural injection, as the siRNA may be co-purified with the RNA and interfere with downstream enzymatic steps. Based on these results, using primers flanking the siRNA target site should be avoided when measuring knockdown of target mRNA by real-time RT-qPCR.</p

A rapid and sensitive method to detect siRNA-mediated mRNA cleavage in vivo using 5′ RACE and a molecular beacon probe

Specific detection of mRNA cleavage by 5′RACE is the only method to confirm the knockdown of mRNA by RNA interference, but is rarely reported for in vivo studies. We have combined 5′-RNA-linker-mediated RACE (5′-RLM-RACE) with real-time PCR using a molecular beacon to develop a rapid and specific method termed MBRACE, which we have used to detect small-interfering RNA (siRNA)-induced cleavage of ApoB, RRM1 and YBX1 transcripts in vitro, and ApoB in vivo. When RNA from siRNA-transfected cells was used for 5′-RLM-RACE and a cleavage site-specific molecular beacon probe was included in subsequent real-time PCR analysis, the specific mRNA cleavage product was detected. Detection of siRNA-mediated cleavage was also observed when RNA from mouse liver following administration of ApoB-specific siRNA was analysed, even in cases where ApoB knockdown measured by real-time PCR was <10%. With its sensitivity and specificity, this variation on the 5′RACE method should prove a useful tool to detect mRNA cleavage and corroborate knockdown studies following siRNA use in vivo

La modulation phéromonale comme moteur de la plasticité comportementale chez deux insectes : les abeilles et les fourmis

Les phéromones sont des substances chimiques relâchées dans l'environnement par un individu qui déclenchent des comportements stéréotypés et/ou des processus physiologiques chez des individus de la même espèce. Cependant, une nouvelle hypothèse suggère que les phéromones non seulement suscitent des réponses innées mais contribuent également à la plasticité comportementale en agissant en "modulateurs" de phénomènes cognitifs. Nous avons étudié l'effet modulateur des phéromones sur les réponses réflexes, la prise de décision, et l'apprentissage chez trois espèces d'insectes qui sont des modèles emblématiques en recherche fondamentale et appliquée : l'abeille Apis mellifera, et les fourmis Camponotus aethiops and Linepithema humile. Dans une première étude, nous avons trouvé qu'une phéromone appétitive diminuait la sensibilité aversive, tandis qu'une phéromone d'alarme augmentait la sensibilité aversive chez l'abeille. Chez L. humile, une phéromone de piste synthétique augmentait la sensibilité au sucre et le temps de nourrissage. Globalement, nos résultats démontrent que certaines phéromones modulent la prépondérance des stimuli aversif et appétitif selon leur valence. De cette manière, elles affecteraient la motivation à s'engager dans des réponses aversives ou appétitives, agissant ainsi comme modulateurs de la plasticité comportementale. Nous avons ensuite déterminé l'effet d'une phéromone d'alarme (l'acide formique) sur la prise de décision et les systèmes de reconnaissance dans le cadre de la discrimination de congénères chez des fourmis charpentières. Nous avons trouvé que la phéromone d'alarme améliorait la discrimination en augmentant l'agressivité envers les non congénères et en la diminuant envers les congénères en même temps. Ces résultats remettent en question le modèle établi de reconnaissance de congénères. Nous proposons donc une version révisée de ce modèle. Enfin, nous avons teste l'effet de l'acide formique sur l'apprentissage et la généralisation. L'acide formique augmentait la discrimination en conditionnement différentiel olfactif aversif. En conditionnement différentiel olfactif appétitif, l'acide formique modulait les dynamiques d'acquisition et la perception de la similarité des odeurs. Nous suggérons que les phéromones affectent la perception des odeurs conditionnées et des renforcements selon la nature des odeurs et leurs valeurs intrinsèques pour l'individu, ainsi que la valence des renforcements. Cette thèse présente les premières analyses intégrées de la modulation phéromonale chez deux taxa : les abeilles et les fourmis. Les résultats présentés nous permettent de comprendre une partie des modes d'action des phéromones et ouvrent la voie à de futures études afin de comprendre les mécanismes qui sous-tendent l'effet modulateur des phéromones.Pheromones are chemical substances released into the environment by an individual, which trigger stereotyped behaviors and/or physiological processes in individuals of the same species. Yet, a novel hypothesis has suggested that pheromones not only elicit innate responses but also contribute to behavioral plasticity by acting as "modulators" of cognitive phenomena. We studied the modulator effect of pheromones on reflex responses, decision making and learning in three insect species that are emblematic models for fundamental and applied research: the honeybee Apis mellifera, and the ants Camponotus aethiops and Linepithema humile. In the first study, we found that an appetitive pheromone decreased aversive responsiveness, while an alarm pheromone increased aversive responsiveness in honey bees. In L. humile, a synthetic trail pheromone increased sucrose responsiveness and feeding time. Overall, our results demonstrate that certain pheromones modulate the salience of aversive and appetitive stimuli according to their valence. In this way, they would affect the motivation to engage in aversive or appetitive responses, thus acting as modulators of behavioral plasticity. We then determined the effect of an alarm pheromone (formic acid) on decision making and recognition systems in the frame of nestmate discrimination in carpenter ants. We found that the alarm pheromone improved discrimination by increasing aggressiveness towards non-nestmates and decreasing aggressiveness towards nestmates at the same time. These results challenge the established model of nestmate recognition. We therefore propose a revised version of this model. Eventually, we tested the effect of formic acid on learning and generalization. Formic acid increased discrimination in aversive olfactory differential conditioning. In appetitive olfactory differential conditioning, formic acid modulated the acquisition dynamics and perceived odor similarity. We suggest that pheromones affect the perception of conditioned odors and reinforcements depending on the nature of the odorants and their intrinsic values for the individual, as well as the valence of the reinforcements. This thesis presents the first integrated analyses of pheromone modulation in two insect taxa: honey bees and ants. The presented results allow us to understand some modes of action of pheromones and pave the way for future studies to understand the underlying mechanisms of this modulator effect of pheromones

Genetic advance and anonymity policies

En los últimos años se ha incrementado en Argentina la cantidad de tratamientos de reproducción asistida con donación de gametos (óvulos y/o espermatozoides). La filiación por técnicas de reproducción asistida heterólogas interroga la tradicional “herencia de sangre” objeto de estudio privilegiado de las ciencias sociales. En las últimas décadas, el paradigma sobre el anonimato de los donantes ha cambiado en muchos países. A su vez, se ha sugerido que los rápidos y generalizados avances en las pruebas genéticas podrían modificar las políticas de anonimato. ¿Cuáles son las consecuencias de fundamentar la revelación de la información genética/identificatoria sobre la base del mayor acceso que posibilitan los test genéticos? La presente reflexión parte de dos vertientes: la pública – que analiza las paradojas que encierra el articulado del nuevo Código Civil y Comercial (2015) – y la íntima, que ubica las coordenadas sobre las que se inscribe la transmisión singular de los orígenes.Nos últimos anos, o número de tratamentos de reprodução assistida com doação de gametas (óvulos e/ou espermatozoides) aumentou na Argentina. A filiação por técnicas de reprodução assistida heteróloga interroga a tradicional “herança sanguínea”, objeto de estudo privilegiado das ciências sociais. Nas últimas décadas, o paradigma do anonimato dos doadores mudou em muitos países. Por sua vez, sugeriu-se que avanços rápidos e generalizados em testes genéticos poderiam modificar as políticas de anonimato. Quais são as consequências de fundamentar a revelação das informações genéticas/de identificação com base no maior acesso que o teste genético torna possível? Esta reflexão parte de duas vertentes: a pública, que analisa os paradoxos dos artigos do novo Código Civil e Comercial (2015); e a íntima, que determina as coordenadas sobre as quais se inscrevem a transmissão singular das origens.In recent years, the number of assisted reproduction treatments with the donation of gametes (ovules and/or sperm) has increased in Argentina. The filiation by heterologous assisted reproduction techniques interrogates the traditional “blood inheritance” object of privileged study of the social sciences. In recent decades, the donor anonymity paradigm has changed in many countries. In turn, it has been suggested that rapid and widespread advances in genetic testing could modify anonymity policies. What are the consequences of substantiating the disclosure of genetic/identifying information based on the greater access that genetic tests allow? This reflection is based on two aspects: the public aspect – which analyzes the paradoxes contained in the articles of the new Civil and Commercial Code (2015) – and the intimate one, which locates the coordinates on which the singular transmission of the origins is inscribed.Fil: Lima, Natacha Salomé. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Rossi, Mariela. Sociedad Argentina de Medicina Reproductiva; Argentin