Histopathological Effects and Growth Reduction in a Susceptible and a Resistant Strain of Heliothis virescens (Lepidoptera: Noctuidae) Caused by Sublethal Doses of Pure Cry1A Crystal Proteins from Bacillus thuringiensis

Martínez‐Ramírez, Amparo C.; Gould, Fred; Ferré, Juan

doi:10.1080/09583159929811

Cited by 59 publications

(46 citation statements)

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“…Considering the two proteins used in this study, one should mention that an amino-peptidase N of 120kDA, located in the membrane of the intestinal epithelium of the Lepidoptera for Cry1Ac (Knight et al, 1994) and cadherin correspond to the receptor for Cry1Ab (Vadlamudi et al, 1993). These epithelium receptors of the midgut of Lepidoptera larvae can be shared by different Cry proteins (Ballester et al, 1999;Martinez-Ramirez et al, 1999), and alterations can make the insects resistant to these toxins (Lee et al, 1995;Schnepf et al, 1998). Estela et al (2004) have shown that Cry1Aa, Cry1Ab and Cry1Ac compete for receptor sites on the membrane of the midgut of H. armigera, and that Cry1Ac and Cry1Ab use different epitopes to bind to the membrane.…”

Section: Resultsmentioning

confidence: 99%

Histopathology and the lethal effect of Cry proteins and strains of Bacillus thuringiensis Berliner in Spodoptera frugiperda J.E. Smith Caterpillars (Lepidoptera, Noctuidae)

Knaak

Franz²,

Santos

et al. 2010

Braz. J. Biol.

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Among the phytophagous insects which attack crops, the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera, Noctuidae) is particularly harmful in the initial growth phase of rice plants. As a potential means of controlling this pest, and considering that the entomopathogen Bacillus thuringiensis Berliner demonstrates toxicity due to synthesis of the Cry protein, the present study was undertaken to evaluate this toxic effect of B. thuringiensis thuringiensis 407 (pH 408) and B. thuringiensis kurstaki HD-73 on S. frugiperda. The following method was used. Both bacterial strains were evaluated in vitro in 1 st instar S. frugiperda caterpillars, by means of histopathological assays. The Cry1Ab and Cry1Ac proteins, codified by the respective strains of B. thuringiensis, were evaluated in vivo by bioassays of 1 st instar S. frugiperda caterpillars in order to determine the Mean Lethal Concentration (LC 50 ). The results of the histopathological analysis of the midget of S. frugiperda caterpillars demonstrate that treatment with the B. thuringiensis thuringiensis strain was more efficient, because the degradations of the microvilosities started 9 hours after treatment application (HAT), while in the B. thuringiensis kurstaki the same effect was noticed only after 12 HAT. Toxicity data of the Cry1Ab and Cry1Ac proteins presented for the target-species LC 50 levels of 9.29 and 1.79 µg.cm , respectivamente. As cepas e proteínas sintetizadas por B. thuringiensis thuringiensis e B. thuringiensis kurstaki são eficientes no controle de S. frugiperda, e poderão ser usadas na produção de novos biopesticidas ou a utilização dos genes na transformação genética de Oryza sativa L. Histopatologia e efeito letal de cepas e proteínas Cry de Bacillus thuringiensis

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Section: Resultsmentioning

confidence: 99%

Histopathology and the lethal effect of Cry proteins and strains of Bacillus thuringiensis Berliner in Spodoptera frugiperda J.E. Smith Caterpillars (Lepidoptera, Noctuidae)

Knaak

Franz²,

Santos

et al. 2010

Braz. J. Biol.

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“…It has been reported that sublethal doses of Cry toxins can be overcome by tolerant insects, and although originally there is tissue damage, the final outcome cannot be distinguished from the outcome for the nontreated controls (28). Therefore, although unlikely, if Cry proteins had temporary subtle deleterious effects on lacewing larvae after exposure to the toxin for a limited time, these effects could be overcome and thus not be detected by an observer.…”

Section: Discussionmentioning

confidence: 99%

“…The mode of action of Cry toxins in all susceptible insect species tested, as well as in nematodes, requires binding to the midgut epithelium (6,37). Normally, specific binding of Cry proteins is shown using BBMV preparations, although immunological detection of ingested toxin has also been used as an alternative method (3,28,35). For small insect species, for which preparation of BBMV could be cumbersome or for which in vitro binding conditions have not been determined, the immunological detection of in vivo bound toxin can be very convenient.…”

Section: Discussionmentioning

confidence: 99%

Lack of Detrimental Effects of Bacillus thuringiensis Cry Toxins on the Insect Predator Chrysoperla carnea : a Toxicological, Histopathological, and Biochemical Analysis

Rodrigo-Simón

Maagd

Avilla

et al. 2006

Appl Environ Microbiol

103

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The effect of Cry proteins of Bacillus thuringiensis on the green lacewing (Chrysoperla carnea) was studied by using a holistic approach which consisted of independent, complementary experimental strategies. Tritrophic experiments were performed, in which lacewing larvae were fed Helicoverpa armigera larvae reared on Cry1Ac, Cry1Ab, or Cry2Ab toxins. In complementary experiments, a predetermined amount of purified Cry1Ac was directly fed to lacewing larvae. In both experiments no effects on prey utilization or fitness parameters were found. Since binding to the midgut is an indispensable step for toxicity of Cry proteins to known target insects, we hypothesized that specific binding of the Cry1A proteins should be found if the proteins were toxic to the green lacewing. In control experiments, Cry1Ac was detected bound to the midgut epithelium of intoxicated H. armigera larvae, and cell damage was observed. However, no binding or histopathological effects of the toxin were found in tissue sections of lacewing larvae. Similarly, Cry1Ab or Cry1Ac bound in a specific manner to brush border membrane vesicles from Spodoptera exigua but not to similar fractions from green lacewing larvae. The in vivo and in vitro binding results strongly suggest that the lacewing larval midgut lacks specific receptors for Cry1Ab or Cry1Ac. These results agree with those obtained in bioassays, and we concluded that the Cry toxins tested, even at concentrations higher than those expected in real-life situations, do not have a detrimental effect on the green lacewing when they are ingested either directly or through the prey.

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“…Strain CP73-3 from H. virescens showed that, compared to a susceptible control strain, there was slower processing of the Cry1Ac protoxin to the active toxin and faster degradation of the toxin (5); no reduction of Cry1Ac or Cry1Ab binding was detected in this strain (7). Finally, a mechanism involving faster damagedcell repair has been proposed to be contributing to the resistance in the H. virescens CP73-3 strain (10).…”

mentioning

confidence: 99%

Different Mechanisms of Resistance to Bacillus thuringiensis Toxins in the Indianmeal Moth

Herrero

Oppert

Ferré

2001

Appl Environ Microbiol

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Susceptibility to protoxin and toxin forms ofr colony also has a protease-mediated mechanism of resistance (B. Oppert, R. Hammel, J. E. Throne, and K. J. Kramer, J. Biol. Chem. 272:23473-23476, 1997) is in agreement with our toxicological data in which this colony has a different susceptibility to the protoxin and toxin forms of Cry1Ab. It is noteworthy that the three colonies used in this work derived originally from ca. 100 insects, which reflects the high variability and high frequency of B. thuringiensis resistance genes occurring in natural populations.

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Histopathological Effects and Growth Reduction in a Susceptible and a Resistant Strain of Heliothis virescens (Lepidoptera: Noctuidae) Caused by Sublethal Doses of Pure Cry1A Crystal Proteins from Bacillus thuringiensis

Cited by 59 publications

References 0 publications

Histopathology and the lethal effect of Cry proteins and strains of Bacillus thuringiensis Berliner in Spodoptera frugiperda J.E. Smith Caterpillars (Lepidoptera, Noctuidae)

Histopathology and the lethal effect of Cry proteins and strains of Bacillus thuringiensis Berliner in Spodoptera frugiperda J.E. Smith Caterpillars (Lepidoptera, Noctuidae)

Lack of Detrimental Effects of Bacillus thuringiensis Cry Toxins on the Insect Predator Chrysoperla carnea : a Toxicological, Histopathological, and Biochemical Analysis

Different Mechanisms of Resistance to Bacillus thuringiensis Toxins in the Indianmeal Moth

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