Regulation of Midgut Growth, Development, and Metamorphosis

Abstract

The insect midgut is an important site of entry for pathogens and insect control agents. This review focuses on recent information related to midgut epithelial growth, metamorphosis, and repair as a defense against pathogens. The roles of stem cell mitogens and differentiation factors are described. Included is a discussion of apoptosis and autophagy in the yellow body. Sloughing, also described, protects the midgut from virus infections and bacterial toxins through death and replacement of affected cells. The mechanisms by which the repair process reduces the effectiveness of pest control strategies are discussed. Primary tissue culture methods also are described, and their value in understanding the mechanisms by which biologically based insecticides work is discussed.

Israeli acute paralysis virus associated paralysis symptoms, viral tissue distribution and Dicer-2 induction in bumblebee workers (Bombus terrestris)

“…In natural conditions, the insect midgut epithelium is the first barrier against viral invasion (Hakim et al, 2010). So a sensitive immune response in the midgut could be beneficial to the host.…”

Hindgut Innate Immunity and Regulation of Fecal Microbiota through Melanization in Insects

“…As in mammals, many pathogens can still escape insect midgut immune system and pass to the hindgut, which is an organ similar to the mammalian large intestine (3,4). Because of similarities with mammals, the insect midgut immune system upon aging, stress, or infection has been extensively studied (4,5). However, as yet, it is unclear whether there is an innate immunity system in mammalian large intestine and the insect hindgut that destroys pathogens before feces excretion.…”

Arylphorin is a mitogen in the Heliothis virescens midgut cell secretome upon Cry1Ac intoxication

“…Primary midgut cell cultures from lepidopteran larvae have been used as an in vitro 88 model to study the molecular cues directing midgut regeneration (Hakim et al, 2010), and are 89 capable of regeneration after intoxication with Bt toxins (Loeb et al, 2001b). A number of 90 peptidic midgut proliferation and/or differentiation factors (MDFs) from mature cell 91 conditioned media and hemolymph have been reported (reviewed in (Hakim et al, 2010 …”

“…A number of 90 peptidic midgut proliferation and/or differentiation factors (MDFs) from mature cell 91 conditioned media and hemolymph have been reported (reviewed in (Hakim et al, 2010 …”