Hemolymph of triatomines presents fungistatic activity against Cryptococcus neoformans and improves macrophage function through MCP-I/TNF-α increase

Triatomines are blood-feeding arthropods belonging to the subfamily Triatominae (Hemiptera; Reduviidae), capable of producing immunomodulatory and water-soluble molecules in their hemolymph, such as antimicrobial peptides (AMPs). In this work, we evaluated the antifungal and immunomodulatory activity of the hemolymph of Meccus pallidipennis (MPH) and Rhodnius prolixus (RPH) against Cryptococcus neoformans. Methods: We assessed the activity of the hemolymph of both insects on fungal growth by a minimum inhibitory concentration (MIC) assay. Further, RAW 264.7 macrophages were cultivated with hemolymph and challenged with C. neoformans. Then, their phagocytic and killing activities were assessed. The cytokines MCP-1, IFN-γ, TNF-α, IL-10, IL-12, and IL-6 were measured in culture supernatants 4- and 48-hours post-infection. Results: Both hemolymph samples directly affected the growth rate of the fungus in a dose-dependent manner. Either MPH or RPH was capable of inhibiting fungal growth by at least 70%, using the lowest dilution (1:20). Treatment of RAW 264.7 macrophages with hemolymph of both insects was capable of increasing the production of MCP-I and TNF-α. In addition, when these cells were stimulated with hemolymph in the presence of C. neoformans, a 2- and a 4-fold increase in phagocytic rate was observed with MPH and RPH, respectively, when compared to untreated cells. For the macrophage killing activity, MPH decreased in approximately 30% the number of viable yeasts inside the cells compared to untreated control; however, treatment with RPH could not reduce the total number of viable yeasts. MPH was also capable of increasing MHC-II expression on macrophages. Regarding the cytokine production, MCP-I and TNF-α, were increased in the supernatant of macrophages treated with both hemolymphs, 4 and 48 hours after stimulation. Conclusion: These results suggested that hemolymph of triatomines may represent a source of molecules capable of presenting antifungal and immunomodulatory activity in macrophages during fungal infection.(AU)

Biological characteristics of Meccus phyllosomus pallidipennis (Hemiptera: Reduviidae: Triatominae) fed on two different hosts

Abstract INTRODUCTION: Different blood meal sources can affect biology of triatomines. METHODS: We studied the influence of two different blood meal sources (rabbits and hens) on five biological parameters in Meccus phyllosomus pallidipennis and collected biological parameters. RESULTS: The cohort fed on rabbits had a shorter median life-cycle and lower mortality rate than that fed on hens. Both cohorts required a similar number of blood meals to reach adulthood. Median longevity and number of blood meals for adults were similar between both cohorts. CONCLUSIONS The studied parameters reflect the high grade of adaptation of M. p. pallidipennis feeding on different hosts.

Parámetros biológicos de Meccus phyllosomus, Meccus mazzottii y sus híbridos de laboratorio / Biological parameters of Meccus phyllosomus, Meccus mazzottii and laboratory bred-hybrids

Se reportan datos sobre el ciclo de vida, número de repastos sanguíneos para mudar de estadio ninfal, mortalidad y el porcentaje de hembras de híbridos de M. phyllosomus x M. mazzottii en comparación con cohortes “puras” de M. phyllosomus (Burmeister) y M. mazzottii (Usinger). El ciclo de vida fue significativamente (P<0,05) más corto en las dos cohortes híbridas, respecto de las parentales. En contraste, no se registraron diferencias significativas (P>0,05) entre cohortes en el número de repastos sanguíneos para mudar de estadio ninfal. El porcentaje de mortalidad (41.8%) de la cohorte parental de M. phyllosomus fue significativamente (P<0,05) mayor que los de las tres cohortes restantes. El porcentaje de hembras fue similar (P>0,05) entre las cuatro cohortes bajo estudio.

Data is reported about life cycle, number of blood meal to molt to next instar, mortality and percentage of females on hybrids from crosses of M. phyllosomus x M. mazzottii compared to “pure” cohorts of M. phyllosomus (Burmeister) and M. mazzottii (Usinger). Recorded life cycle was significantly ( P<0,05) shorter in both hybrids cohorts with respect to the two parental ones. In contrast, non significant (P>0,05) differences were recorded in the number of blood meals to molt to next instar when the four studied cohorts were compared. Mortality percentage (41.8%) on the parental cohort of M. phyllosomus was significantly (P<0,05) higher than those in the three other studied cohorts. Female percentage was similar (P>0,05) when the four studied cohorts were compared.

Presencia de Meccus longipennis y Triatoma recurva en el estado de Durango, México / Presence of Meccus longipennis and Triatoma recurva in the state of Durango, Mexico

Se reporta por primera vez la recolecta de ejemplares de Meccus longipennis (Usinger) y de Triatoma recurva (Stål) en el estado de Durango. La búsqueda de triatominos se realizó durante 12 meses (septiembre 2010-agosto 2011) en cuatro comunidades de dos municipios (Pueblo Nuevo y Mezquital) del estado de Durango. Se recolectaron 71 ejemplares de M. longipennis y seis de T. recurva provenientes mayoritariamente del interior de las viviendas humanas (recámaras). La presencia de M. longipennis en el área abre la posibilidad de un riesgo potencial de transmisión de Trypanosoma cruzi Chagas a las poblaciones humanas del área estudiada.

The collection of Meccus longipennis (Usinger) and of Triatoma recurva (Stål) in the state of Durango is reported for the first time. Both species were collected during twelve months (from September 2010 to August 2011) in four localities of two municipalities (Pueblo Nuevo y Mezquital) in the state of Durango. Seventy one specimens of M. longipennis and six of T. recurva were collected mostly from indoors of human dwellings (bedrooms). Presence of M. longipennis means a potential risk of transmission of Trypanosoma cruzi Chagas to human populations in the study area.

Occurrence of hybrids and laboratory evidence of fertility among three species of the Phyllosoma complex (Hemiptera: Reduviidae) in Mexico

In seven studied communities of Western Mexico, triatomine specimens were sympatrically collected, some with atypical morphological characteristics in contrast to pure specimens, which were presumed to be hybrids. More than 200 specimens of Meccus pallidipennis and Meccus longipennis with brown-yellow markings on dorsal connexival segments were collected in Ahuacapán and Quitupan. In La Mesa, more than 60 specimens similar to Meccus picturatus in most morphological characteristics (including size) were collected, although they presented a largely yellowish corium like M. pallidipennis. Interfertility was proven between all of the studied wild hybrid specimens, as well as between all the experimental laboratory hybrids. Two different phenotypes (M. picturatus and M. longipennis) were obtained from crosses between M. picturatus x M. picturatus and M. longipennis x M. longipennis from the three studied localities in state of Nayarit as from La Mesita. Results support the hypothesis that the subspecific ranking of those triatomines may, therefore, be more appropriate because reproductive isolation has not been developed and complete interbreeding was recorded.