Selection of new chemicals to be used in conditioned aversion for non-lethal predation control

Globally, native predators and scavengers are threatened through the incidence of illegal poisoning due to increasing human-wildlife conflicts. The use of conditioned taste aversion (CTA) may mitigate such conflicts. CTA is a robust learning paradigm that occurs when animals associate a food with a discomfort induced by a chemical, thereby avoiding that food in subsequent encounters. We reviewed the potential of 167 chemical compounds to be used in CTA, considering effects, margin of safety, accessibility, and detectability. After the review, 15 compounds fulfilled the required characteristics, but only five (thiabendazole, thiram, levamisole, fluconazole and fluralaner) were finally selected to be tested in CTA assays with dogs. Of the tested compounds, thiabendazole, thiram and levamisole caused target food rejection by dogs and reduced the time spent eating during post-conditioning. However, despite being microencapsulated, levamisole appeared to be detectable by dogs, whereas thiram and thiabendazole were not. Fluconazole and fluralaner did not produce any CTA effect. Thiabendazole, thiram and levamisole can therefore induce CTA, and thus are potential candidates as aversive compounds for wildlife management. Thiram is an undetectable, relatively safe and accessible compound that can induce CTA in canids, and opens new possibilities to develop methods of non-lethal predation control.This study is a result of CGL2013–40975-R project, from I+D+I National Plan funded by the Spanish Ministry of Economy and Competitiveness. Jorge Tobajas benefitted from a FPI PhD scholarship (BES-2014-068987) funded by the Spanish Ministry of Economy and Competitiveness.Peer reviewe

The reaction mechanism of metallo-beta-lactamases is tuned by the conformation of an active site mobile loop

Carbapenems are "last resort" β-lactam antibiotics used to treat serious and life-threatening health care-associated infections caused by multidrug-resistant Gram-negative bacteria. Unfortunately, the worldwide spread of genes coding for carbapenemases among these bacteria is threatening these life-saving drugs. Metallo-β-lactamases (MβLs) are the largest family of carbapenemases. These are Zn(II)-dependent hydrolases that are active against almost all β-lactam antibiotics. Their catalytic mechanism and the features driving substrate specificity have been matter of intense debate. The active sites of MβLs are flanked by two loops, one of which, loop L3, was shown to adopt different conformations upon substrate or inhibitor binding, and thus are expected to play a role in substrate recognition. However, the sequence heterogeneity observed in this loop in different MβLs has limited the generalizations about its role. Here, we report the engineering of different loops within the scaffold of the clinically relevant carbapenemase NDM-1. We found that the loop sequence dictates its conformation in the unbound form of the enzyme, eliciting different degrees of active-site exposure. However, these structural changes have a minor impact on the substrate profile. Instead, we report that the loop conformation determines the protonation rate of key reaction intermediates accumulated during the hydrolysis of different β-lactams in all MβLs. This study demonstrates the existence of a direct link between the conformation of this loop and the mechanistic features of the enzyme, bringing to light an unexplored function of active-site loops on MβLs.Fil: Palacios, Antonela Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Mojica, María F.. Case Western Reserve University; Estados UnidosFil: Giannini, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Taracila, Magdalena A.. Case Western Reserve University; Estados Unidos. Louis Stokes Veterans Affairs Medical Center; Estados UnidosFil: Bethel, Christopher R.. Louis Stokes Veterans Affairs Medical Center; Estados UnidosFil: Alzari, Pedro M.. Institut Pasteur de Paris; FranciaFil: Otero, Lisandro Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Klinke, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Llarrull, Leticia Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Bonomo, Robert A.. Case Western Reserve University; Estados UnidosFil: Vila, Alejandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentin

Spatiotemporal variations of organochlorine pesticides in an apex predator: Influence of government regulations and farming practices

Background: Intensification of agricultural practices has caused several negative effects to the environment. The use of fertilizers and pesticides may alter geochemical cycles or cause direct wildlife intoxication. Detrimental effects of organochlorine pesticides (OCPs) have forced the authorities to ban or restrict its use. This study evaluates the variation in levels of OCPs in a sentinel species in relation to changes in government regulations and the spatial configuration of agricultural practices around the nests. Methods: Between 2003 and 2007, we analysed OCP levels in 256 blood samples of Eurasian Eagle-owl (Bubo bubo) chicks nesting in area of intensive commercial agriculture with historical frequent use of pesticides, in South-eastern Spain. We studied year-to-year variations in OCP concentrations and their relation with land use configuration around raptor nests by Generalized Linear Mixed Models (GLMM). Results: OCPs were detected in 100% samples surveyed in 2003 and 2004, while dropped to 27% in 2005, 6.8% in 2006 and 6.3% in 2007, coinciding with the ban of OCPs. The presence of the main OCPs was related to agricultural practices. In particular, endosulfan and lindane were related to irrigated crops and urban areas, while DDT-related compounds and dieldrin were associated with dry land farming. Conclusions: OCP concentrations in blood samples of Eurasian Eagle-owls may respond quickly to the implementations of new regulations about the use of agricultural products. This raptor was confirmed as a good sentinel species allowing rapid detection of changes in pesticides use

A schematic sampling protocol for contaminant monitoring in raptors

Birds of prey, owls and falcons are widely used as sentinel species in raptor biomonitoring programmes. A major current challenge is to facilitate large-scale biomonitoring by coordinating contaminant monitoring activities and by building capacity across countries. This requires sharing, dissemination and adoption of best practices addressed by the Networking Programme Research and Monitoring for and with Raptors in Europe (EURAPMON) and now being advanced by the ongoing international COST Action European Raptor Biomonitoring Facility. The present perspective introduces a schematic sampling protocol for contaminant monitoring in raptors. We provide guidance on sample collection with a view to increasing sampling capacity across countries, ensuring appropriate quality of samples and facilitating harmonization of procedures to maximize the reliability, comparability and interoperability of data. The here presented protocol can be used by professionals and volunteers as a standard guide to ensure harmonised sampling methods for contaminant monitoring in raptors

Gestos, tecnologías y sociedades: Tendencias y emergencias en tiempos de pospandemia

La tecnología hace parte de la humanidad como el medio con el cual la sociedad externaliza, apropia y articulasu existencia con los territorios y otras especies. Su fuerza instrumental responde a unas adaptaciones que en el último siglo han consolidado una relación de interdependencia con la aparatología al tiempo que se han modificado ritmos, lenguajes y formas de concebir la realidad. La tecnología se ha convertido en un agente inherente de la sociedad, y es uno de los factores que afecta y cambia el comportamiento humano y las dinámicas sociales, muestra de esto se evidenció en la pandemia del Coronavirus. Periodo en donde el Estado, la industria, la salud, la educación, etc., reinventaron sus procesos para dar continuidad a la estructura de la vida cotidiana

Conditioned food aversion mediated by odour cue and microencapsulated levamisole to avoid predation by canids

Worldwide, predators and humans are in conflict for resources such as game species or livestock, especially in the case of wild canids. One non-lethal method to reduce predation is conditioned food aversion (CFA), in which animals learn to avoid a food due to the illness after ingestion, caused by the addition of an undetected chemical compound. CFA can be enhanced by adding an artificial odour cue, in a process known as taste-potentiated odour aversion (TPOA). We tested CFA and TPOA with three experimental groups of penned dogs. Food was offered with a combination of microencapsulated levamisole + vanilla odour (ODO), microencapsulated levamisole (LEV), or plain food as a control. The aims were (a) to test whether dogs detected the microencapsulated levamisole, (b) to analyse the strength and extinction time of CFA induced by microencapsulated levamisole, and (c) to analyse the strength and extinction time of TPOA. Two-choice tests were carried out during 11 post-conditioning months, and two reinforcements with microencapsulated levamisole were performed during the first post-conditioning month. In the first post-conditioning test, ODO and LEV groups ate significantly less untreated food than control group. After reinforcement, the dogs in LEV group resumed eating the food. Three of four dogs in ODO group showed long-lasting CFA until the 11th month. These results show that TPOA could be used to induce odour aversion on canids and that the odour cue overshadows the slight bitter taste of microencapsulated levamisole. These results show TPOA as a promising tool to reduce predation by wild canids.This study is a result of CGL2013–40975-R project, from I + D + I National Plan funded by the Spanish Ministry of Economy and Competitiveness. Jorge Tobajas benefitted from a FPI PhD scholarship (BES-2014-068987) funded by the Spanish Ministry of Economy and Competitiveness.Peer reviewe

Temporal Persistence of Bromadiolone in Decomposing Bodies of Common Kestrel (Falco tinnunculus)

Bromadiolone is a second generation anticoagulant rodenticide (SGAR) used to control pest rodents worldwide. SGARs are frequently involved in secondary poisoning in rodent predators due to their persistence and toxicity. This study aims to evaluate the persistence of bromadiolone in liver at different stages of carcass decomposition in experimentally-dosed common kestrels (Falco tinnunculus) to understand the possibility of detecting bromadiolone in cases of wildlife poisoning and the potential risk of tertiary poisoning. Twelve individuals were divided into the bromadiolone-dose group (dosed with 55 mg/kg b.w) and the control group. Hepatic bromadiolone concentrations found in each stage of decomposition were: 3000, 2891, 4804, 4245, 8848, and 756 ng/g dry weight at 1–2 h (fresh carcass), 24 h (moderate decomposition), 72 h, 96 h (advanced decomposition), seven days (very advanced decomposition), and 15 days (initial skeletal reduction) after death, respectively. Liver bromadiolone concentrations in carcasses remained relatively stable over the first four days and raised on day 7 of decomposition under the specific conditions of this experiment, presenting a risk of causing tertiary poisoning. However, at the initial skeletal reduction stage, liver bromadiolone concentration declined, which should be considered to interpret toxicological analyses and for proper diagnosis. This experimental study provides for the first time some light to better understand the degradation of SGARs in carcasses in the wild

Estudio preliminar sobre la degradación postmortem del diclofenaco en aves silvestres

Resumen del trabajo presentado al XXII Congreso Español de Toxicología y VI Iberoamericano, celebrado en Valencia (España) del 28 al 30 de junio de 2017.El diclofenaco (DCF) es un fármaco antiinflamatorio no esteroideo considerado como uno de los más devastadores tóxicos ambientales tras comprobarse ser el responsable del descenso brusco en las poblaciones de buitres del subcontinente indio. En España, la Agencia Española de Medicamentos y Productos Sanitarios (AEMPS), ha autorizado recientemente el uso de diclofenaco para ganado lo cual, puede supone un potencial riesgo de consecuencias impredecibles sobre las poblaciones de aves carroñeras y desconocemos si para otras especies aviares. La mejora en los métodos analíticos así como la obtención de datos complementarios forenses, relacionados fundamentalmente con la data de la muerte y la degradación del DCF, nos permitirá estimar valores de referencia útiles para futuros diagnósticos de causa de muerte por este hecho. En este estudio, se emplearon 4 ejemplares de gaviotas patiamarillas (Larus michahellis) y un cernícalo común (Falco tinnunculus) procedentes del CRFSa los que se suministró por vía oral 50 mg DCF. Estos individuos fueron sacrificados con solución de pentobarbital sódico al 20%, a diferentes tiempos tras la toma (1 h, 2h, 3h y 4h). Posteriormente, se llevó a cabo la extracción simple del DFC con metanol y congelación y detección mediante HPLC-MS/TOF, observándose que las concentraciones más altas de DCF en hígado se detectaba a la hora tras la ingestión. En segundo ensayo se emplearon 3 ejemplares de gaviotas patiamarilla a las cuales se les administraron 50 mg de diclofenaco sódico por vía oral y sacrificio a la hora tras ingestión. Se tomaron muestras de hígado cada 6 horas durante 72 horas. Además, se usaron sondas de penetración en cadáveres dónde se almacenaban valores de humedad, temperatura ambiental y muscular durante todo el estudio. Tras extracción del DFC observamos como la concentración de DCF en hígado desciende en más de un 70% en las primeras 24 horas postmortem alcanzando un nivel de estabilización que se mantiene durante las 72 horas de estudioFundación Séneca (Proyecto MASCA’2014, ref. 19481/PI/14), MINECO (Proyecto RECODEP, ref. CGL2013-40975-R).Peer reviewe

Conditioned taste aversion as a tool for reducing predation by wild canids

Resumen del trabajo presentado al 12th International Mammalogical Congress (IMC): "Advances in mammalogy in a changing world", celebrado en Perth (Australia) del 9 al 14 de julio de 2017.Predator control has traditionally been used to solve the conflict between wild carnivores and humans for resources, leading many carnivore species to the brink of extinction. We are assessing the use of conditioned taste aversion (CTA) as a tool to reduce predation by wild canids. Firstly, we performed an experiment with penned dogs to identify suitable substances to be used as CTA agents in wild canids. We compared pre- and post-conditioning consumption of untreated food as a measure of CTA response. Levamisole (anthelminthic) and Thiram (fungicide) reduced food consumption in the conditioned dogs between 15% and 48% and between 23% and 32% respectively. Both substances generated CTA in dogs with no adverse health effects. A field experiment was performed in two localities with Thiram as CTA agent. Nine foxes were marked with GPS collars and ear tags and simulated partridge nests were monitored with camera-traps. A control area (n = 5 foxes) and a treatment area (n = 4 foxes) were delimited in each locality. During the pre-conditioning phase, nest predation rate was 27.1% and 22.6% in the treatment and control areas, respectively. Foxes were exposed to 60 mg kg-1 of Thiram during the conditioning phase. During the post-conditioning phase, no nest was preyed by treated foxes, whereas foxes in the control area preyed on 13.1% of nests. These results show that Thiram can be safely used as CTA agent to prevent nest predation by foxes. CTA opens new opportunities to mitigate conflicts between humans and predators.Peer Reviewe

Relationship of the toxicity of pesticide formulations and their commercial restrictions with the frequency of animal poisonings

Deliberate poisoning of domestic animals and wildlife with commercial formulations of pesticides has been documented worldwide. We have compiled the analytical results obtained by four Spanish Laboratories of Veterinary Toxicology since 1990. The frequency of poisonings and the intentional use of pesticides were compared between formulations with restricted and unrestricted use, including the toxicity of the commercial formulations as a covariant in the model. The frequency of poisoning was inversely related with the lethal dose of specific formulations, but not with the amounts consumed in agriculture in Spain. The intentional illegal use of some pesticides as poisons was not affected by the commercial restriction of their formulations, but was inversely correlated with their LD50. The examination of the data permits us to detect three highly toxic compounds (aldicarb, carbofuran, and strychnine), more widely implicated in animal poisonings than other compounds of similar toxicity.M. Martínez-Haro was supported by a postgraduate grant (I3P) from Consejo Superior de Investigaciones Científicas. Work done at the Instituto de Investigación en Recursos Cinegéticos was supported with a grant of the Ministerio de Educación y Ciencia (CGL2004-02568/BOS).Peer reviewe