Ultraestrutura e função das glândulas salivares de Podisus nigrispinus (Hemiptera: Pentatomidae)

• Autor(a) principal: Castrillon, Luis Carlos Martinez
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/934
• topic: Podisus nigrispinus - Controle biológico; Glândulas salivares; Enzimas; N,N-dimetilanilina; 1,2,3-tritiepano; Podisus - Biological control; Salivary glands; enzymes; N, N-dimethylaniline; 1,2,3-tritiepano; CNPQ::CIENCIAS BIOLOGICAS::ZOOLOGIA::FISIOLOGIA DOS GRUPOS RECENTES

Podisus nigrispinus Dallas (Hemiptera: Pentatomidae) is a zoophytophagous insect that has a potential in biological control because its nymphs and adults prey on various insects. They insert their mouthparts and inject the contents of their salivary glands in their prey to kill them. Although it is understood that the saliva of this predator is toxic, the toxic compounds responsible for the prey death remains unknown. To identify the components of the saliva of P. nigrispinus, we evaluated the ultrastructure and cytochemistry of the salivary glands of this insect. Cytochemistry evaluation identified the compounds of the saliva of P. nigrispinus responsible for the death of Anticarsia gemmatalis prey. The salivary system of P. nigrispinus has consists of a pair of principal salivary glands, which are bilobed with a short anterior and a long posterior lobe, and a pair of tubular accessory glands. The cells of both the glands are well developed with a predominance of mitochondria and rough endoplasmic reticulum and with basal plasma membrane infoldings, indicating that both the glands play a role in the transport of hemolymph substances and protein synthesis. The cytochemical tests demonstrated positive reactions for carbohydrate, protein, and acid phosphatase in the cells of both the salivary glands. An injection of the saliva of P. nigrispinus exposed to enzyme inhibitors and proteases and extracted at the ether phase caused mortality of A. gemmatalis larvae, with LD50 = 1.91 and LD90 = 4.34 μL. These saliva fractions were identified as N,N-dimethylaniline and 1,2,3-trithiepane, and the injection of the first compound showed an LC50 = 136.1 nL and LC90 = 413.8 nL, suggesting that these non- proteineous compound is responsible for the saliva toxicity of P. nigrispinus. The ultrastructural and cytochemical features suggested participation of the principal and accessory salivary glands in the secretion of proteinaceous and non-proteinaceous toxic substances in the saliva of this insect. This was further confirmed by identification of N,N-dimethylaniline and 1,2,3-trithiepane responsible for the death of A. gemmatalis. This is the first study reporting the toxic compounds of the saliva of this insect.