Bacillus thuringiensis endotoxins: action on the insect midgut

Pietrantonio, Patricia V.; Gill, Sarjeet S.

doi:10.1007/978-94-009-1519-0_13

Cited by 31 publications

(24 citation statements)

References 92 publications

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“…The comprehension of the molecular basis of toxin-receptor interaction will be useful to develop new Cry toxins with novel specificities and improved toxic activities, contributing to the management of insect resistance in the field. Most of the binding studies have been conducted in lepidopteran larvae and Cry1 toxins (Pietrantonio and Gill, 1996). Few studies were done in coleopteran or in dipteran larvae (Belfiore et al, 1994;Soberón et al, 2007a,b).…”

Section: Discussionmentioning

confidence: 97%

Midgut GPI-anchored proteins with alkaline phosphatase activity from the cotton boll weevil (Anthonomus grandis) are putative receptors for the Cry1B protein of Bacillus thuringiensis

Martins

Monnerat

Queiroz

et al. 2010

Insect Biochemistry and Molecular Biology

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Section: Discussionmentioning

confidence: 97%

Midgut GPI-anchored proteins with alkaline phosphatase activity from the cotton boll weevil (Anthonomus grandis) are putative receptors for the Cry1B protein of Bacillus thuringiensis

Martins

Monnerat

Queiroz

et al. 2010

Insect Biochemistry and Molecular Biology

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“…Inward fluid leakage leads to osmotic lysis and rapid cell death (Pietrantonio and Gill, 1996). The toxins are activated by proteases in the alkaline insect midgut, and attach to specific receptors on columnar cell microvilli.…”

Section: Fig 8 Breakdown Of Cell Types In the Apoptotic Populationsmentioning

confidence: 99%

Apoptosis in cultured midgut cells fromHeliothis virescenslarvae exposed to various conditions

Loeb

Hakim

Martin

et al. 2000

Arch. Insect Biochem. Physiol.

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We exposed midgut cells from primary cultures of Heliothis virescens larvae to cell-free previously used medium, the Vaughn X and HyQ SFtrade mark media used for serum-free culture of insect cell lines which do not support H. virescens midgut cells, and to toxin from Bacillus thuringiensis. A statistically significant increase in the percent of dying cells was counted in cell populations in Vaughn X medium. Use of the TUNEL method to detect apoptosis indicated a low rate (7.2%) of apoptosis in control cultures grown in Heliothis medium, an increase to approximately 20% in previously used and HyQ SFtrade mark media, and to approximately 45% of cells remaining after exposure to and initial destruction by B. thuringiensis toxin. Apoptotic nuclei were predominant (approximately 6%) in mature columnar cells in control cultures. Approximately 1% of goblet, stem, and differentiating cells were apoptotic. However, apoptosis rose to 12% in stem and differentiating cells exposed to used and unsuitable medium. B. thuringiensis exposure to toxin for 2-3 days resulted in visible membrane damage and necrosis, causing the death of 84% of the cells as measured by both the TUNEL and Annexin methods. Some of the columnar cells and stem and differentiating cells that remained also contained apoptotic nuclei. Stem and differentiating cells normally replace dying mature cells in the midgut. Thus, exposure of cultures of H. virescens midgut cells to adverse environments such as unsuitable or poisonous media appeared to induce down-regulation of the cell populations by apoptosis.

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“…It is generally thought that these toxinmediated pores lead to cell lysis that subsequently causes insect death de Maagd et al, 2003;Schnepf et al, 1998). However, alternative models of insect death that involve cellular signaling leading to cell death have also been suggested (Griko et al, 2004;Pietrantonio and Gill, 1996;Zhang et al, 2005).…”

Section: Introductionmentioning

confidence: 99%