Morphological regional differences of epithelial cells along the midgut in Diatraea saccharalis Fabricius (Lepidoptera: Crambidae) larvae

Abstract

Diferenças Morfológicas Regionais das Células Epiteliais ao Longo do Intestino Médio de Larvas deDiatraea saccharalis Fabricius (Lepidoptera: Crambidae)RESUMO -A broca da cana, Diatraea saccharalis Fabricius, é uma praga da cana-de-açúcar e outras plantações. O objetivo deste trabalho foi caracterizar variações morfológicas nas células epiteliais (colunares, caliciformes e regenerativas) ao longo do intestino médio de larvas de D. saccharalis. Fragmentos do intestino médio (anterior, mediano e posterior) foram fi xados e processados para microscopia de luz e eletrônica de varredura. Existem diferenças morfológicas citoquímicas e ultraestruturais nas células epiteliais, dependendo da sua localização no intestino médio. A superfície apical de algumas células colunares exibe projeções citoplasmáticas que aumentam em número e volume da região anterior para a posterior do intestino médio. Existe aumento dos grânulos PAS-positivos (Reação de Schiff) no citoplasma apical das células colunares e regenerativas, da região anterior para a posterior. A câmara das células caliciformes, na região anterior do intestino médio, mostra seu ápice estreito, enquanto que na posterior essa porção da câmara é alargada; as evaginações citoplasmáticas da câmara são pequenas e fi nas no ápice, sendo numerosas, longas e mais espessas na porção basal. Os resultados sugerem que o intestino médio da broca da cana apresenta duas regiões morfologicamente distintas, a anterior e posterior; a região mediana é uma região de transição.PALAVRAS-CHAVE: Morfologia, broca da cana, histoquímica, microscopia eletrônica de varredura, microscopia de luz ABSTRACT -The sugarcane borer, Diatraea saccharalis Fabricius, is a pest to sugarcane and many other crops. This work aims to characterize morphological variability in the epithelial cells (columnar, goblet and regenerative) along the midgut of D. saccharalis larvae. Fragments of the midgut (anterior, middle and posterior regions) were fi xed and processed by light and scanning electron microscopy. There are both cytochemical and ultrastructural differences in the morphology of the epithelial cells, depending on their localization along the midgut. The apical surface of columnar cells shows an increase in both number and size of the apical protrusions from the anterior to the posterior midgut regions.There is an increase in the amount of PAS-positive (Periodic Acid-Schiff Reaction) granules detected in the cytoplasm of both the columnar and regenerative cells, from the anterior to the posterior region. The goblet cell apical surface is narrow in the anterior region, and enlarged in the posterior midgut; the chamber's cytoplasm extrusion are small and thin at the apical cavity surface, being thicker, longer and more numerous at the basal portion of the cavity. Our results suggest that the sugarcane borer midgut has two morphologically different regions, the anterior and the posterior; the middle region is a transitional region.

A morphometric study of the midgut in resistant and non-resistant Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) larvae to its nucleopolyhedrovirus (AgMNPV)

“…Such differences could be mainly related to the release of cytoplasmatic portions and apical micro-vesicles toward the lumen, as well as to the high quantity of some organelles as Golgi complex and rough endoplasmic reticulum. Similar observations were detected by Pinheiro and Gregório (2001) in D. saccharalis who reported columnar cells with different aspects regarding the quantity of mitochondria and basal invaginations along the midgut. Besides, the goblet cells actively participated in physiological changes of the midgut, as these cells were also more developed in RL than in SL A. gemmatalis.…”

Impact of Bt cotton on the immune system and histology of the midgut of the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

“…These cells were identified in the present study showing particular characteristics of a pattem similar to the one reported by Correia et al (2008) for S. frugiperda. This pattem only differed by the absence of endocrine cells, since additional ultrastmctural and/or immunohistochemical analyses are required to detect these (Pinheiro et al, 2008;Sousa et al, 2009). The moderate changes observed in the epithelium of the midgut of 5. frugiperda caterpillars are different from those in other noctuids that are susceptible to CrylAc, such as the cotton leafworm, A. argillace (Sousa et al, 2010).…”

Physiological and biochemical effect of neem and other Meliaceae plants secondary metabolites against Lepidopteran insects

“…Among the three regions, the midgut region has particularly been the most studied, because alterations on it affect the growth and development of insects as a result of changes in the physiological events that depend on meal intake, absorption and transformation (Mordue and Blackwell, 1993; Nisbet, 2000; De Sousa et al, 2009). The epithelium of the midgut in Lepidoptera is composed of columnar cells which are responsible for absorption and enzymes secretion, goblet cells for ionic homeostasis, endocrine cells for endocrine function and the regenerative cells for epithelium renewal (Genta et al, 2006; Pinheiro et al, 2008; De Sousa et al, 2009). …”