RESUMO
The southern cattle tick (Rhipicephalus microplus) represents one of the ectoparasites with the greatest distribution worldwide. Infestations by this arthropod can cause a decrease in the production of meat and milk, as well as anaemia and the transmission of bacterial and parasitic agents. For this reason, several active molecules have been developed to control these arthropods. A widely used group of ixodicides are pyrethroids, especially cypermethrin, which have knockdown effects on ticks. Resistance to cypermethrin has been reported in ticks since the 2000s; it was registered for the first time in Mexico in 2009. Even though multiple studies have evaluated resistance with conventional tests, there are few studies in Mexico that have identified the presence of single nucleotide polymorphisms (SNPs) associated with resistance. Hence, the aim of this work was to monitor three mutations associated with resistance in the sodium/chlorine channel in eight populations of ticks from northern Veracruz. Engorged adult females were collected from which genomic DNA was extracted. Subsequently, three mutations in domains II and III of parasodium channel gene were detected by conventional PCR and sequencing. Global alignments were done with the reference sequences deposited in GenBank. A total of 116 engorged females were analysed, of which 10 tested positive for G184C and C190A of domain II of the parasodium channel gene. T2134A was present in domain III in a single production unit. This is the first work where molecular monitoring of cypermethrin resistance has been carried out in the northern zone of the state of Veracruz.
Assuntos
Artrópodes , Piretrinas , Rhipicephalus , Animais , Feminino , Rhipicephalus/genética , México , Mutação , Piretrinas/farmacologiaRESUMO
Fleas and ticks represent the two main groups of ectoparasites that infest companion animals. In particular, the flea Ctenocephalides felis felis and several members of the Rhipicephalus sanguineus complex are the main vectors of a wide range of pathogens on the American continent. They are competent vectors for several members of the genus Rickettsia, which encompass at least 15 pathogenic obligate intracellular bacteria that colonize the endothelial cells of vertebrates. In Mexico, 10 species of Rickettsia belonging to three groups have been detected in six species of ectoparasites from dogs in 9 of the 32 states of the country. However, in some larger regions of the country, active epidemiological surveillance has not been carried out. For this reason, the aim of this study was to identify the presence of members of the genus Rickettsia in fleas and ticks of dogs and cats in the state of Puebla, Mexico. A cross-sectional study was carried out to collect ectoparasites of dogs and cats during August to November 2019. Samples were fixed in 70% ethanol and examined to identify the presence of Rickettsia DNA by the amplification and sequencing of specific fragments of the gltA and ompB genes using conventional PCR. The recovered sequences were compared with those deposited in GenBank, and phylogenetic analyses were carried out to identify the position of the pathogens detected with respect to the valid species previously reported worldwide. Additionally, ecological parameters of the ectoparasite infestations were also calculated. We recovered 196 ectoparasites belonging to two species, 33 C. felis felis and 163 R. sanguineus s.l. (Rhipicephalus linnaei), parasitizing 46 hosts (42 dogs and 4 cats) in 11 localities of the state of Puebla. We detected the presence of Rickettsia felis in three pools of C. felis felis, and five from R. sanguineus s.l. Our work provides the first record of R. felis in hard ticks of Mexico and Central America, with new collection localities for this pathogen in central Mexico.
Assuntos
Doenças do Gato , Doenças do Cão , Felis , Infestações por Pulgas , Rhipicephalus sanguineus , Rickettsia felis , Rickettsia , Sifonápteros , Animais , Gatos , Cães , Sifonápteros/microbiologia , Rickettsia felis/genética , Doenças do Gato/parasitologia , Filogenia , Estudos Transversais , Células Endoteliais , México/epidemiologia , Doenças do Cão/microbiologia , Infestações por Pulgas/epidemiologia , Infestações por Pulgas/veterinária , Rickettsia/genéticaRESUMO
The acrosome reaction (AR) is the exocytosis of the acrosomal vesicle in response to different physiological and non-physiological stimuli. Particularly in mammals, the AR is needed for sperm to fuse with the oocyte plasma membrane, and it occurs only in capacitated sperm. Previous evidence in the literature indicates that extracellular ATP induces the AR in capacitated human and bovine spermatozoa, but its receptor has not yet been identified. The aim of this work was to define a putative ATP receptor in rat spermatozoa using pharmacological and biochemical approaches. We found that ATP induced the AR only in capacitated rat spermatozoa, which was inhibited in the presence of two general inhibitors of ATP receptors (P2 receptors), Suramin, and oxidized ATP (oATP), and one inhibitor of P2X receptor (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid [PPADS]). In addition, the AR induced by ATP in capacitated rat spermatozoa was inhibited by brilliant blue-G (BB-G) and 17-ß-oestradiol, two blockers of P2X7 receptors. Moreover, the ATP analog 2'(3')-O-(4-benzoylbenzoyl) ATP (BzATP) was almost 500 times more potent than ATP to induce the AR, which agrees with the pharmacology of a P2X7 receptor. Here, we show the presence of P2X7 receptor by Western blot and its localization in the tail and acrosome by indirect immunofluorescence. Finally, we quantify the presence of ATP in the rat oviduct during the estrous cycle. We found that the ATP concentration within the lumen of the oviduct is similar to those required to induce acrosome reaction, which agree with its role during in vivo fertilization. Therefore, our results strongly suggest that ATP induces the AR in capacitated rat spermatozoa through a P2X7 receptor, which may be functional during in vivo fertilization.
Assuntos
Reação Acrossômica/efeitos dos fármacos , Acrossomo/efeitos dos fármacos , Trifosfato de Adenosina/farmacologia , Agonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X7/efeitos dos fármacos , Acrossomo/metabolismo , Animais , Relação Dose-Resposta a Droga , Ciclo Estral/metabolismo , Feminino , Masculino , Oviductos/metabolismo , Antagonistas do Receptor Purinérgico P2X/farmacologia , Ratos Sprague-Dawley , Receptores Purinérgicos P2X7/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fatores de TempoRESUMO
Se estudiaron los daños primarios producidos por la radiación gamma en el ADN de cepas de Escherichia coli portadoras de la fusión génica sulA::lacZ y de mutaciones en diferentes genes de reparación del ADN. Además, se determinó su radiosensibilidad. Las cepas con mutaciones en los genes recN y uvrA fueron más sensibles que la tipo salvaje. Esto concuerda con estudios previos donde se demostró que los genes rec y uvr participaban en la reparación del daño en el ADN producido por los rayos gamma. En las cepas mutantes se encontraron diferencias significativas en los niveles de expresión del gen sulA en relación con el tipo salvaje. Se discute la utilidad de las cepas estudiadas como biosensores de genotoxicidad así como en estudios de radioprotección(AU)
Assuntos
Escherichia coli/crescimento & desenvolvimento , Escherichia coli/genética , Escherichia coli/efeitos da radiação , Raios gama/efeitos adversos , Reparo do DNA , Dano ao DNA/efeitos da radiaçãoRESUMO
Se estudiaron los daños primarios producidos por la radiación gamma en el ADN de cepas de Escherichia coli portadoras de la fusión génica sulA::lacZ y de mutaciones en diferentes genes de reparación del ADN. Además, se determinó su radiosensibilidad. Las cepas con mutaciones en los genes recN y uvrA fueron más sensibles que la tipo salvaje. Esto concuerda con estudios previos donde se demostró que los genes rec y uvr participaban en la reparación del daño en el ADN producido por los rayos gamma. En las cepas mutantes se encontraron diferencias significativas en los niveles de expresión del gen sulA en relación con el tipo salvaje. Se discute la utilidad de las cepas estudiadas como biosensores de genotoxicidad así como en estudios de radioprotección
Assuntos
Dano ao DNA , Reparo do DNA , Escherichia coli , Raios gama , Resposta SOS em Genética/efeitos da radiaçãoRESUMO
Se estudió la radiosensibilidad y la cinética de inducción de eventos de conversión y reversión génica en la cepa D7 de Sacharomyces cerevisiae frente a radiación gamma, en rangos de dosis entre 100-800 Gy y entre 50-300 Gy, respectivamente. Se utilizó una fuente de 60Co PX-g-30 con una tasa de dosis 49,43 Gy/min. La curva de supervivencia celular mostró un DL50 de 150 Gy. La cinética de muerte celular fue lineal con un ajuste superior a 98 por ciento. La inducción de eventos de conversión génica fue significativa respecto al control a partir de 50 Gy. Por el contrario, la reversión génica fue significativa solo a partir de 200 Gy. En general, las frecuencias de eventos de conversión génica fueron superiores a las de reversión, esto sugiere que la radiación gamma induce preferentemente eventos recombinogénicos. Tanto para los eventos de conversión como de reversión génica se obtuvo una dependencia exponencial de la dosis de radiación gamma. Se discutió sobre la utilidad relativa del ensayo para estudios de mutagénesis y antimutagénesis(AU)
Assuntos
Conversão Gênica/efeitos da radiação , Raios gama/efeitos adversos , Dano ao DNA , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/efeitos da radiaçãoRESUMO
Se estudió la radiosensibilidad y la cinética de inducción de eventos de conversión y reversión génica en la cepa D7 de Sacharomyces cerevisiae frente a radiación gamma, en rangos de dosis entre 100-800 Gy y entre 50-300 Gy, respectivamente. Se utilizó una fuente de 60Co PX-g-30 con una tasa de dosis 49,43 Gy/min. La curva de supervivencia celular mostró un DL50 de 150 Gy. La cinética de muerte celular fue lineal con un ajuste superior a 98 por ciento. La inducción de eventos de conversión génica fue significativa respecto al control a partir de 50 Gy. Por el contrario, la reversión génica fue significativa solo a partir de 200 Gy. En general, las frecuencias de eventos de conversión génica fueron superiores a las de reversión, esto sugiere que la radiación gamma induce preferentemente eventos recombinogénicos. Tanto para los eventos de conversión como de reversión génica se obtuvo una dependencia exponencial de la dosis de radiación gamma. Se discutió sobre la utilidad relativa del ensayo para estudios de mutagénesis y antimutagénesis