RESUMO
BACKGROUND: Triatoma guasayana is considered an emerging vector of Chagas disease in the Southern Cone of South America. The presence of a triatomine population with brachypterous individuals, in which both wings are reduced, has recently been reported for this species. The aim of the present study was to determine if flight-related traits varied across populations, if these traits could explain differences in flight capacity across populations and if flight-related traits are associated with geographic and/or climatic variation. METHODS: The study involved 66 male T. guasayana specimens from 10 triatomine populations. Digital images of wing, head and pronotum were used to estimate linear and geometric morphometric variables. Variations in size and shape were analysed using one-way analysis of variance and canonical variate analysis (CVA), respectively. Mantel tests were applied to analyse the relationship between morphometric and geographic distances, and the association between size measurements was analysed using Pearson's correlation. We explored covariation between size and shape variables using partial least square analyses (PLS). The association of geographic and climatic variables with size measurements was tested using linear regression analyses. We performed PLS analyses for shape measurements. RESULTS: Wing size differed significantly across triatomine populations. The CVA showed that wing shape of the brachypterous population is well discriminated from that of the other populations. The Mantel test showed a positive and significant association between wing shape and geographic distances. The heads of the brachypterous population were significantly larger than those of the other populations. Similar to wing shape, the head shape of the brachypterous population was well discriminated from those of the other populations. Pronotum width did not show significant differences across populations. Geographic and climatic factors were associated with size and shape of both the wing and head, but not with pronotum width. CONCLUSIONS: Most of the traits related to flight dispersal varied across populations. Wing shape and head shape were found to be better markers for differentiated morphological variation across populations. Head measurements also varied in accordance with this condition. Geographic and climatic variables were associated with most of the flight-related traits.
Assuntos
Doença de Chagas , Triatoma , Humanos , Animais , Masculino , Fenótipo , América do Sul , Variação Biológica da População , Asas de AnimaisRESUMO
BACKGROUND: Chagas is a complex and multidimensional socio-environmental health phenomenon, in which different components converge and interact. Historically, this disease was associated with insect vectors found in the rural environment. However, in the Americas, we are currently facing a new paradigm, in which different scenarios allow maintaining the vectorial transmission of the parasite through triatomine populations that either occasionally enter the dwellings or colonize urban environments. METHODOLOGY/PRINCIPAL FINDINGS: Records of scientific reports available in the PubMed and LILACS search engines were retrieved, using three criteria according to the main triatomine genera of epidemiological importance and to the general scientific production on Chagas disease in urban contexts. Results showed that records on the occurrence of vectors in urban dwellings began to increase in the last three decades. Results also showed that the main species of triatomines collected inside dwellings (18 in total) belong mainly to the genera Triatoma and Panstrongylus, with most species (16/18, 88.8%) infected with the parasite, and that infestation of triatomine species occurs in all types of cities (small, medium and large, including megalopolises), from Argentina to the USA. CONCLUSIONS/SIGNIFICANCE: Urban Chagas represents a new challenge that adds a different dimension to the problem of Chagas disease due to the particular characteristics of the lifestyle in urban agglomerates. The new scenario will require adaptations of the programs of control of vector to this shift from rural to urban settlements.
Assuntos
Doença de Chagas , Panstrongylus , Triatoma , Trypanosoma cruzi , Animais , Humanos , Doença de Chagas/parasitologia , Triatoma/parasitologia , Panstrongylus/parasitologia , Cidades/epidemiologiaRESUMO
Vector-borne transmission of Chagas disease in urban areas of Argentina has been an overlooked phenomena. We conducted the first comprehensive cross-sectional study of domestic infestation with Triatoma infestans and vector infection with Trypanosoma cruzi in a metropolitan area of San Juan, Argentina. Our results document the occurrence of T. infestans infected with T. cruzi in human sleeping quarters. In this urban setting, we also show that infestation was associated with construction materials, the presence of chickens, cats and a large number of dogs that can provide blood meals for the vector. Our findings reveal new challenges for vectorial control agencies.
Assuntos
Doença de Chagas , Triatoma , Trypanosoma cruzi , Animais , Argentina , Gatos , Galinhas , Estudos Transversais , Cães , Insetos VetoresRESUMO
Vector-borne transmission of Chagas disease in urban areas of Argentina has been an overlooked phenomena. We conducted the first comprehensive cross-sectional study of domestic infestation with Triatoma infestans and vector infection with Trypanosoma cruzi in a metropolitan area of San Juan, Argentina. Our results document the occurrence of T. infestans infected with T. cruzi in human sleeping quarters. In this urban setting, we also show that infestation was associated with construction materials, the presence of chickens, cats and a large number of dogs that can provide blood meals for the vector. Our findings reveal new challenges for vectorial control agencies.
Assuntos
Animais , Gatos , Cães , Triatoma , Trypanosoma cruzi , Doença de Chagas , Argentina , Galinhas , Estudos Transversais , Insetos VetoresRESUMO
Los peces larvívoros han sido estudiados como posibles agentes de control biológico de larvas y pupas de mosquitos a través de sus interacciones tróficas. El uso de peces nativos para el control de mosquitos puede tener beneficios tanto para la biodiversidad acuática como para la salud humana. La evaluación del efecto de la vegetación sobre la eficacia depredadora es fundamental para determinar si esta especie puede usarse como un agente de control biológico. Con el objetivo de evaluar a Jenynsia multidentata (Jenyns, 1842) como agente de biocontrol de Culex pipiens Linnaeus, 1758, probamos su capacidad depredadora en presencia o ausencia de vegetación acuática en condiciones de laboratorio. Se llevaron a cabo dos experimentos independientes. El consumo de larvas a una densidad de 60 larvas (6 larvas / l) se redujo significativamente con el aumento de la vegetación. Por otro lado, cuando la densidad larval fue de 120 (12 larvas / l), la capacidad depredadora de J. multidentata no varía en la presencia o ausencia de vegetación. Este resultado indicó que el efecto de la vegetación en el consumo podría estar relacionado con la densidad de presas, ya que a mayor densidad de presas se podría incrementar la probabilidad de encuentro entre depredador y presa. Jenynsia multidentata es un buen consumidor en presencia de vegetación y podría ser usado como un potencial agente de control biológico de larvas de mosquitos en ambientes naturales con características similares a las probadas en estos experimentos.(AU)
Larvivorous fish have been studied as potential biocontrol agents of mosquito larvae and pupae through their trophic interactions. The use of native sh for mosquito control may have benets for both aquatic biodiversity and human health. Evaluating the effect of vegetation on the predatory efficacy is fundamental to determine if this species can be used as a biocontrol agent. With the aim of evaluating Jenynsia multidentata (Jenyns, 1842) as a biocontrol agent of Culex pipiens Linnaeus, 1758, we tested its predatory capacity in the presence or absence of aquatic vegetation under laboratory conditions. Two independent experiments were conducted. Larval consumption at a density of 60 larvae (6 larvae/l) was significantly reduced with the vegetation increased. On the other hand, when the larval density was 120 (12 larvae/l), the predatory capacity of J. multidentata did not vary in the presence or absence of vegetation. This result indicated that vegetation effect on consumption could be related to prey density, since at the higher density of prey the probability of predator-prey encounter might be increased. Jenynsia multidentata is a good consumer in presence of vegetation and could be used as a potential biocontrol agent of mosquito larvae in natural environments with similar characteristics to the ones tested in these experiments.(AU)
Assuntos
Animais , Peixes/anatomia & histologia , Peixes/crescimento & desenvolvimento , Larva , Comportamento Predatório , Controle Biológico de VetoresRESUMO
Los peces larvívoros han sido estudiados como posibles agentes de control biológico de larvas y pupas de mosquitos a través de sus interacciones tróficas. El uso de peces nativos para el control de mosquitos puede tener beneficios tanto para la biodiversidad acuática como para la salud humana. La evaluación del efecto de la vegetación sobre la eficacia depredadora es fundamental para determinar si esta especie puede usarse como un agente de control biológico. Con el objetivo de evaluar a Jenynsia multidentata (Jenyns, 1842) como agente de biocontrol de Culex pipiens Linnaeus, 1758, probamos su capacidad depredadora en presencia o ausencia de vegetación acuática en condiciones de laboratorio. Se llevaron a cabo dos experimentos independientes. El consumo de larvas a una densidad de 60 larvas (6 larvas / l) se redujo significativamente con el aumento de la vegetación. Por otro lado, cuando la densidad larval fue de 120 (12 larvas / l), la capacidad depredadora de J. multidentata no varía en la presencia o ausencia de vegetación. Este resultado indicó que el efecto de la vegetación en el consumo podría estar relacionado con la densidad de presas, ya que a mayor densidad de presas se podría incrementar la probabilidad de encuentro entre depredador y presa. Jenynsia multidentata es un buen consumidor en presencia de vegetación y podría ser usado como un potencial agente de control biológico de larvas de mosquitos en ambientes naturales con características similares a las probadas en estos experimentos.
Larvivorous fish have been studied as potential biocontrol agents of mosquito larvae and pupae through their trophic interactions. The use of native sh for mosquito control may have benets for both aquatic biodiversity and human health. Evaluating the effect of vegetation on the predatory efficacy is fundamental to determine if this species can be used as a biocontrol agent. With the aim of evaluating Jenynsia multidentata (Jenyns, 1842) as a biocontrol agent of Culex pipiens Linnaeus, 1758, we tested its predatory capacity in the presence or absence of aquatic vegetation under laboratory conditions. Two independent experiments were conducted. Larval consumption at a density of 60 larvae (6 larvae/l) was significantly reduced with the vegetation increased. On the other hand, when the larval density was 120 (12 larvae/l), the predatory capacity of J. multidentata did not vary in the presence or absence of vegetation. This result indicated that vegetation effect on consumption could be related to prey density, since at the higher density of prey the probability of predator-prey encounter might be increased. Jenynsia multidentata is a good consumer in presence of vegetation and could be used as a potential biocontrol agent of mosquito larvae in natural environments with similar characteristics to the ones tested in these experiments.
Assuntos
Animais , Comportamento Predatório , Controle Biológico de Vetores , Larva , Peixes/anatomia & histologia , Peixes/crescimento & desenvolvimentoRESUMO
RESUMEN Los peces larvívoros han sido estudiados como posibles agentes de control biológico de larvas y pupas de mosquitos a través de sus interacciones tróficas. El uso de peces nativos para el control de mosquitos puede tener beneficios tanto para la biodiversidad acuática como para la salud humana. La evaluación del efecto de la vegetación sobre la eficacia depredadora es fundamental para determinar si esta especie puede usarse como un agente de control biológico. Con el objetivo de evaluar a Jenynsia multidentata (Jenyns, 1842) como agente de biocontrol de Culex pipiens Linnaeus, 1758, probamos su capacidad depredadora en presencia o ausencia de vegetación acuática en condiciones de laboratorio. Se llevaron a cabo dos experimentos independientes. El consumo de larvas a una densidad de 60 larvas (6 larvas / l) se redujo significativamente con el aumento de la vegetación. Por otro lado, cuando la densidad larval fue de 120 (12 larvas / l), la capacidad depredadora de J. multidentata no varía en la presencia o ausencia de vegetación. Este resultado indicó que el efecto de la vegetación en el consumo podría estar relacionado con la densidad de presas, ya que a mayor densidad de presas se podría incrementar la probabilidad de encuentro entre depredador y presa. Jenynsia multidentata es un buen consumidor en presencia de vegetación y podría ser usado como un potencial agente de control biológico de larvas de mosquitos en ambientes naturales con características similares a las probadas en estos experimentos.
ABSTRACT Larvivorous fish have been studied as potential biocontrol agents of mosquito larvae and pupae through their trophic interactions. The use of native sh for mosquito control may have benets for both aquatic biodiversity and human health. Evaluating the effect of vegetation on the predatory efficacy is fundamental to determine if this species can be used as a biocontrol agent. With the aim of evaluating Jenynsia multidentata (Jenyns, 1842) as a biocontrol agent of Culex pipiens Linnaeus, 1758, we tested its predatory capacity in the presence or absence of aquatic vegetation under laboratory conditions. Two independent experiments were conducted. Larval consumption at a density of 60 larvae (6 larvae/l) was significantly reduced with the vegetation increased. On the other hand, when the larval density was 120 (12 larvae/l), the predatory capacity of J. multidentata did not vary in the presence or absence of vegetation. This result indicated that vegetation effect on consumption could be related to prey density, since at the higher density of prey the probability of predator-prey encounter might be increased. Jenynsia multidentata is a good consumer in presence of vegetation and could be used as a potential biocontrol agent of mosquito larvae in natural environments with similar characteristics to the ones tested in these experiments.
RESUMO
San Juan presenta una alta infestación por Triatoma infestans en áreas urbanas, por ello nos propusimos estudiar los factores de riesgo asociados con la transmisión vectorial del T. cruzi en ámbito urbano del Departamento Rawson. Se empleo un diseño observacional y transversal de enfoque mixto; cuali-cuantitativo. Se encuestó sobre las características de la vivienda, de movilidad, de vulnerabilidad socio-sanitarias y de conocimientos de la enfermedad. Se realizaron encuestas entomológicas en las viviendas y serológicas en la población y en los perros. Mediante modelos multinivel se evaluó la importancia relativa de los factores para explicar la seropositividad a T. cruzi y la infestación por Triatoma infestans. Se realizó análisis espacial para estudiar la distribución de la infección e infestación. Se llevaron a cabo encuestas dialogadas a referentes de la comunidad y de los equipos de salud y vectores. Se evaluaron 347/758 viviendas visitadas, el 13,8% presentó infestación que se asoció al número de sitios en el peridomicilio y techos de machimbre y/o caña. Se realizó diagnóstico en 614/1057 habitantes detectándose una prevalencia del 3,09%. Se estudiaron 130 caninos de los cuales 10,0% fueron reactivos. Ninguna variable pudo explicar la infección, se registró una tendencia que asocia positivamente la vulnerabilidad con la presencia de personas infectadas. La infestación no se identificó estadísticamente agregada a nivel de manzana mientras que la infección en perro y humanos si, fenómeno observado también en el análisis espacial. De las encuestas dialogadas surge la necesidad de realizar más difusión, de promover acciones de control integrales y de generar adaptaciones a los protocolos de control vectorial. Nuestro estudio pone en evidencia la extensión y complejidad del problema de la transmisión vectorial de la enfermedad de Chagas en ámbitos urbanos e identifica grandes desafíos para la ejecución de acciones de control
Assuntos
Doença de ChagasRESUMO
The activation of the rate-limiting step in steroid biosynthesis, that is the transport of cholesterol into the mitochondria, is dependent on PKA-mediated events triggered by hormones like ACTH and LH. Two of such events are the protein tyrosine dephosphorylation mediated by protein tyrosine phosphatases (PTPs) and the release of arachidonic acid (AA) mediated by two enzymes, ACS4 (acyl-CoA synthetase 4) and Acot2 (mitochondrial thioesterase). ACTH and LH regulate the activity of PTPs and Acot2 and promote the induction of ACS4. Here we analyzed the involvement of PTPs on the expression of ACS4. We found that two PTP inhibitors, acting through different mechanisms, are both able to abrogate the hormonal effect on ACS4 induction. PTP inhibitors also reduce the effect of cAMP on steroidogenesis and on the level of StAR protein, which facilitates the access of cholesterol into the mitochondria. Moreover, our results indicate that exogenous AA is able to overcome the inhibition produced by PTP inhibitors on StAR protein level and steroidogenesis. Then, here we describe a link between PTP activity and AA release, since ACS4 induction is under the control of PTP activity, being a key event for AA release, StAR induction and steroidogenesis.
Assuntos
Ácido Araquidônico/metabolismo , Coenzima A Ligases/metabolismo , Proteínas de Membrana Transportadoras/biossíntese , Proteínas Tirosina Fosfatases/metabolismo , Neoplasias do Córtex Suprarrenal , Hormônio Adrenocorticotrópico/farmacologia , Animais , Linhagem Celular , Linhagem Celular Tumoral , Tumor de Células de Leydig , Hormônio Luteinizante/farmacologia , Masculino , CamundongosRESUMO
We have described that, in adrenal and Leydig cells, the hormonal regulation of free arachidonic acid (AA) concentration is mediated by the concerted action of two enzymes: an acyl-CoA thioesterase (MTE-I or ARTISt) and an acyl-CoA synthetase (ACS4). In this study we analyzed the potential regulation of these proteins by hormonal action in steroidogenic cells. We demonstrated that ACS4 is rapidly induced by adrenocorticotropin (ACTH) and cAMP in Y1 adrenocortical cells. The hormone and its second messenger increased ACS4 protein levels in a time and concentration dependent way. Maximal concentration of ACTH (10 mIU/ml) produced a significant effect after 15 min of treatment and exerted the highest increase (3-fold) after 30 min. Moreover, (35)S-methionine incorporation showed that the increase in ACS4 protein levels is due to an increase in the de novo synthesis of the protein. On the contrary MTE-I protein levels in Y1 and MA-10 cells did not change after steroidogenic stimuli. In contrast with the effect observed on protein levels, stimulation of both cell lines did not change ACS4 RNA levels during the first hour of treatment, indicating that the effect of both stimuli is exerted at the level of ACS4 protein synthesis.StAR protein induction has a key role on the activation of steroidogenesis since this protein increases the rate of the limiting step of the whole process. In agreement with the fact that the inhibition of ACS4 activity by triacsin C blocks cAMP-stimulated progesterone production by MA-10 Leydig cells, here we demonstrated that ACS4 inhibition also reduces StAR protein levels. Moreover, exogenous AA was able to overcome the effect of triacsin C on both events, StAR induction and steroidogenesis. These results were confirmed by experiments using ACS4-targeted siRNA which result in a reduction in both ACS4 and StAR protein levels. The concomitant decrease in steroid production was overcome by the addition of AA to the knocked-out cells. In summary, this study suggests that in adrenal and Leydig cells the hormonal action prompts the synthesis of a labile protein, ACS4, which activity is involved in the regulation of AA release and is essential for steroidogenesis and StAR protein induction.
Assuntos
Hormônio Adrenocorticotrópico/metabolismo , Ácido Araquidônico/metabolismo , Coenzima A Ligases/metabolismo , Transdução de Sinais , Animais , Northern Blotting , Western Blotting , Linhagem Celular Tumoral , Imunoprecipitação , Masculino , Camundongos , RNA Interferente Pequeno/genética , Ratos , Ratos WistarRESUMO
The ACTH signaling pathway includes both PKA activation as well as PKA-dependent tyrosine phosphatase activation. In addition, the action of this hormone also includes the regulation of the intracellular levels of arachidonic acid (AA) by the concerted action of two enzymes: an acylCoA-thioesterase and an acyl-CoA-synthetase (ACS4). This work describes the production and characterization of a specific ACS4 antibody, which was used to analyze the effect of ACTH on ACS4 protein level in Y1 adrenocortical cells and the putative relationship between tyrosine phosphatases and ACS4. The antiserum was obtained from rabbits immunized with the recombinant ACS4. This immunogen was produced in bacteria and eluted from an acrylamide gel after SDS-PAGE separation of a partially purified bacteria lysate. When used in Western blot analysis, the antibody obtained specifically recognized only one protein of the molecular mass corresponding to ACS4, in Y1 cells and in several rat tissues. Using the antibody described here, we analyzed the effect of ACTH stimulation on ACS4 protein level. The hormone produced an increase of this acyl-CoA synthetase in Y1 adrenocortical cells. Moreover, this effect was mimicked by cAMP and partially reduced by a tyrosine phosphatase inhibitor. We propose that ACTH regulates ACS4 protein levels through a PKA-dependent mechanism that could involve also PTP activity.