Variability of defensin genes from a Mexican endemic Triatominae: Triatoma (Meccus) pallidipennis (Hemiptera: Reduviidae)

Abstract

Chagas disease remains a serious health problem for countries where the most common mode of transmission is infection contracted from the feces of a Triatominae insect vector. In México, 32 species of Triatoma have been identified; amongst them, Triatoma (Meccus) pallidipennis is an endemic species reported to have high percentages of infection with T. cruzi. Defensins, cysteine-rich cationic peptides, are a family of antimicrobial peptides (AMPs); the synthesis of these molecules is crucial for insect’s immune defense. In the present study, the genes encoding defensins in T. pallidipennis were sequenced with the purpose of identifying the variability of these genes in a Mexican vector of T. cruzi. We found 12 different genes encoding three mature peptides, all of which had the typical folding of a functional insect defensin. In this work two Defensins type 1 and one type 4 were identified. The pro-peptide domain was highly variable and the mature peptide was not. This is the first report focus on variability of defensins from an epidemiologically important Triatoma in Mexico.

Trends in taxonomy of Triatomini (Hemiptera, Reduviidae, Triatominae): reproductive compatibility reinforces the synonymization of Meccus Stål, 1859 with Triatoma Laporte, 1832

“…Taxonomy is a fundamental science for the entomo-epidemiology of Chagas disease, because correctly classifying triatomines can assist in the activity of vector control programs [ 28 ]. Even though since 2014 the generic status of the species grouped in Meccus has been changed to Triatoma , several authors continued publishing articles using the Meccus nomenclature as valid [ 20 , 29 – 46 ] and, quite mistakenly, as Triatoma ( Meccus ) pallidipennis [ 47 – 49 ]—since Meccus after the genus Triatoma (between parentheses) represents a subgenus and, so far, there are no valid subgenera in the subfamily Triatominae.…”

In silico identification and expression analyses of Defensin genes in the mealworm beetle Tenebrio molitor

“…In the Defensin genes (12 genes encoding three mature peptides) of Triatoma (Meccus) pallidipennis , the pro‐peptide was found to be variable, but the mature peptide was not (Diaz‐Garrido et al . 2018). In Megalobrama amblycephala (blunt snout bream), β‐Defensin1 and β‐Defensin2 showed four and five conserved cysteine residues, respectively (Liang et al .…”

Enfermedad de Chagas: biología y transmisión de Trypanosoma cruzi

“…La ingestión de tripomastigotes estimula la respuesta inmunológica en el intestino del triatomino R. prolixus, pues la expresión de los genes de lisozimas, defensinas y óxido nítrico sintasa aumenta tras la ingestión de la sangre infectada; esto puede ser una reacción de defensa general contra los microorganismos. La respuesta inmune de los insectos comprende respuestas celulares (hemocitos) y humorales, como la generación de profenoloxidasa (PPO), cascadas de coagulación de la hemolinfa, especies reactivas de oxígeno (ROS), especies reactivas de nitrógeno (RNS) y péptidos antimicrobianos (AMPs) (Garcia et al, 2010;Schaub et al, 2011;Díaz-Garrido, Sepúlveda-Robles, Martínez-Martínez & Espinoza, 2018). Se han descrito tres procesos de defensa en los triatominos contra los parásitos: fagocitosis, formación de nódulos y encapsulación.…”