Optimisation of DNA extraction from individual sand flies for PCR amplification

CALIGIURI, LORENA G.; SANDOVAL, ADOLFO E.; MIRANDA, JOSE C.; PESSOA, FELIPE A.; SANTINI, MARÍA S.; SALOMÓN, OSCAR D.; SECUNDINO, NAGILA F. C.; *CHRISTINA B. MCCARTHY

Manaos

Encuentro; Encuentro Inaugural de la Latin American Society for Vector Ecology (LA SOVE); 2019

Latin American Society for Vector Ecology

Numerous protocols have been published for extracting DNA from phlebotomines. Nevertheless, their small size is generally an issue in terms of yield, efficiency, and purity, for large-scale individual sand fly DNA extractions when using traditional methods. Even though this can be circumvented with commercial kits, these are generally cost-prohibitive for developing countries. We encountered these limitations when analyzing field-collected Lutzomyia spp. by polymerase chain reaction (PCR) and, for this reason, we evaluated various modifications on a previously published protocol, the most significant of which was a different lysis buffer that contained Ca2+ (buffer TESCa). This ion protects proteinase K against autolysis, increases its thermal stability, and could have a regulatory function for its substrate-binding site. Individual sand fly DNA extraction success was confirmed by amplification reactions using internal control primers that amplify a fragment of thecacophony gene. To the best of our knowledge, this is the first time a lysis buffer containing Ca2+ has been reported for the extraction of DNA from sand flies.