Aprimoramento de matrizes poliméricas naturais para liberação controlada de compostos atrativos para Lutzomyia longipalpis (Diptera, Psychodidae, Phlebotominae)
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Data
28-09-22
Autores
Bueno, Ana Carolina
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Universidade Estadual Paulista (Unesp)
Resumo
Flebotomíneos são insetos responsáveis pela transmissão dos agentes etiológicos das leishmanioses e são de difícil controle e monitoramento. A busca por iscas atrativas a fim de auxiliar nas coletas desses vetores, impulsiona estudos relevantes do ponto de vista epidemiológico. A ecologia química contribui com a investigação de novas alternativas de iscas atrativas, pois aborda possíveis substâncias químicas responsáveis pela interação entre organismos. Além da identificação de compostos atrativos, outra necessidade, dentro dessa área, é a forma como esses atrativos são liberados em campo. Em estudos prévios, foi desenvolvido um liberador a partir dos polímeros naturais, goma gelana e pectina para liberação de compostos atrativos para flebotomíneos e, o presente trabalho buscou o aprimoramento desse sistema de liberação. Foram desenvolvidas quatro formulações do sistema de liberação, alterando as proporções da goma gelana e pectina e a concentração do AlCl3: Sistema 1 (1:1 3%), Sistema 2 (1:1 5%), Sistema 3 (4:1 3%) e Sistema 4 (4:1 5%). Nesses sistemas foram acrescentados compostos atrativos para Lutozomyia longpipalpis, hexanol, octenol e nonanol, anteriormente estudados em laboratório. Foi possível identificar o formato que obteve melhor estabilidade na volatilização desses compostos: 21 cm3 – cilíndrico e achatado, além de compreender melhor os processos físicos e químicos envolvidos, como a capacidade de reutilização do material. Observou-se que a cada reuso, a liberação do 1-hexanol se tornou-se mais estável. Foi possível atingir a máxima estabilidade de liberação do 1-hexanol após introduzir as matrizes poliméricas em cápsulas de plástico e, consequentemente, aumentar o tempo de liberação do composto. O Sistema 2, introduzido em cápsula, apresentou ótimos resultados de liberação do 1-hexanol nas condições de umidade natural e elevada e também apresentou eficiência na atratividade de fêmeas de Lu. longipalpis nos testes em túnel de vento. Os resultados obtidos conferem um caráter promissor para a utilização desse sistema de liberação como iscas de captura para o vetor.
Sandflies are insects responsible for transmitting etiological agents of leishmaniasis and are difficult to control and monitor. The search for attractive baits to assist the collection of these vectors drives relevant studies from an epidemiological point of view. In this way, chemical ecology contributes to the investigation of new alternatives of attractive baits, as it addresses possible chemical compounds responsible for the interaction between organisms. In addition to the identification of attractive compounds, another need within this area is how these attractants are released in the field. In previous studies, a release system from natural polymers of gellan gum and pectin to release attractive compounds for sandflies was developed, and the present work improved these release systems. Four formulations of the release system were developed, changing the proportions of gellan gun and pectin and the concentration of AlCl3: System 1 (1:1 3%), System 2 (1:1 5%), System 3 (4:1 3%) and System 4 (4:1 5%). In these systems, attractive compounds for Lutzomyia longipalpis, hexanol, octenol and nonanol, previously studied in the laboratory, were added. It was possible to select the best format that presents stability in the volatilization of these compounds: 21 cm3 – cylindrical and flat; and understand the physical and chemical processes involved, such as the ability to reuse the material, with each reuse the release of 1-hexanol becoming more stable. It was possible to achieve maximum release stability of 1- hexanol after introducing the polymeric matrices into plastic capsules and, consequently, increasing the release time of the compound. System 2 introduced in a capsule presented excellent results of 1-hexanol release under natural and high humidity conditions and efficiency in the attractiveness of Lu. longipalpis females in the wind tunnel tests, providing a promising feature for their use as capture baits for the vector.
Sandflies are insects responsible for transmitting etiological agents of leishmaniasis and are difficult to control and monitor. The search for attractive baits to assist the collection of these vectors drives relevant studies from an epidemiological point of view. In this way, chemical ecology contributes to the investigation of new alternatives of attractive baits, as it addresses possible chemical compounds responsible for the interaction between organisms. In addition to the identification of attractive compounds, another need within this area is how these attractants are released in the field. In previous studies, a release system from natural polymers of gellan gum and pectin to release attractive compounds for sandflies was developed, and the present work improved these release systems. Four formulations of the release system were developed, changing the proportions of gellan gun and pectin and the concentration of AlCl3: System 1 (1:1 3%), System 2 (1:1 5%), System 3 (4:1 3%) and System 4 (4:1 5%). In these systems, attractive compounds for Lutzomyia longipalpis, hexanol, octenol and nonanol, previously studied in the laboratory, were added. It was possible to select the best format that presents stability in the volatilization of these compounds: 21 cm3 – cylindrical and flat; and understand the physical and chemical processes involved, such as the ability to reuse the material, with each reuse the release of 1-hexanol becoming more stable. It was possible to achieve maximum release stability of 1- hexanol after introducing the polymeric matrices into plastic capsules and, consequently, increasing the release time of the compound. System 2 introduced in a capsule presented excellent results of 1-hexanol release under natural and high humidity conditions and efficiency in the attractiveness of Lu. longipalpis females in the wind tunnel tests, providing a promising feature for their use as capture baits for the vector.
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Palavras-chave
sistema de liberação, hexanol, Lu. longipalpis