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Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis
Microbial entomopathogen—based bioinsecticides are recognized as alternatives to synthetic pesticides. Insects defend themselves against microbial pathogens by innate mechanisms, including increased phenoloxidase (PO) activity, but its relationship with microbial bioinsecticides efficacy is little k...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
University of Wisconsin Library
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3593704/ https://www.ncbi.nlm.nih.gov/pubmed/23414117 http://dx.doi.org/10.1673/031.012.8001 |
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author | Valadez-Lira, J.A. Alcocer-Gonzalez, J.M. Damas, G. Nuñez-Mejía, G. Oppert, B. Rodriguez-Padilla, C. Tamez-Guerra, P. |
author_facet | Valadez-Lira, J.A. Alcocer-Gonzalez, J.M. Damas, G. Nuñez-Mejía, G. Oppert, B. Rodriguez-Padilla, C. Tamez-Guerra, P. |
author_sort | Valadez-Lira, J.A. |
collection | PubMed |
description | Microbial entomopathogen—based bioinsecticides are recognized as alternatives to synthetic pesticides. Insects defend themselves against microbial pathogens by innate mechanisms, including increased phenoloxidase (PO) activity, but its relationship with microbial bioinsecticides efficacy is little known. This study evaluated the differences in PO activity at different developmental stages of the tobacco budworm Heliothis virescens Fabricius (Lepidoptera: Noctuidae), Indian meal moth Plodia interpunctella (Hübner) (Pyralidae), beet armyworm Spodoptera exigua (Hübner) (Noctuidae), and cabbage looper Trichoplusia ni (Hübner) (Noctuidae). Additionally, 2(nd)- and 4(th)-instars were exposed to the LC(50) value of the commercial Bacillus thuringiensis (Bt) spray, Biobit(®). The percentage of insecticidal activity (IA%) on 2(nd)-instar Biobit—exposed larvae was approximately the predicted 50 % mortality for all species except S. exigua. With all 4(th) instar Biobit—exposed larvae, mortality was not significantly different from that of unexposed larvae. Unexposed insects had a significantly higher PO activity in pre—pupae and pupae than early—instar larvae and adults, whereas PO activity was higher in adult females than in males. Correlation analysis between IA% and PO activity revealed significant r—values (p < 0.01) in 2(nd) instar H. virescens (r = 0.979) and P. interpunctella (r = 0.930). Second instar Biobit—exposed P. interpunctella had 10 times more PO activity than unexposed larvae. Similarly, the amount of total protein was lower in 4(th) instar Biobit—exposed H. virescens and higher in S. exigua. Therefore, the results indicated a relationship between Biobit susceptibility and PO activity in some cases. This information may be useful if the Biobit application period is timed for a developmental stage with low PO activity. However, more studies are needed to determine the correlation of each insect with a particular bioinsecticide. |
format | Online Article Text |
id | pubmed-3593704 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | University of Wisconsin Library |
record_format | MEDLINE/PubMed |
spelling | pubmed-35937042013-03-13 Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis Valadez-Lira, J.A. Alcocer-Gonzalez, J.M. Damas, G. Nuñez-Mejía, G. Oppert, B. Rodriguez-Padilla, C. Tamez-Guerra, P. J Insect Sci Article Microbial entomopathogen—based bioinsecticides are recognized as alternatives to synthetic pesticides. Insects defend themselves against microbial pathogens by innate mechanisms, including increased phenoloxidase (PO) activity, but its relationship with microbial bioinsecticides efficacy is little known. This study evaluated the differences in PO activity at different developmental stages of the tobacco budworm Heliothis virescens Fabricius (Lepidoptera: Noctuidae), Indian meal moth Plodia interpunctella (Hübner) (Pyralidae), beet armyworm Spodoptera exigua (Hübner) (Noctuidae), and cabbage looper Trichoplusia ni (Hübner) (Noctuidae). Additionally, 2(nd)- and 4(th)-instars were exposed to the LC(50) value of the commercial Bacillus thuringiensis (Bt) spray, Biobit(®). The percentage of insecticidal activity (IA%) on 2(nd)-instar Biobit—exposed larvae was approximately the predicted 50 % mortality for all species except S. exigua. With all 4(th) instar Biobit—exposed larvae, mortality was not significantly different from that of unexposed larvae. Unexposed insects had a significantly higher PO activity in pre—pupae and pupae than early—instar larvae and adults, whereas PO activity was higher in adult females than in males. Correlation analysis between IA% and PO activity revealed significant r—values (p < 0.01) in 2(nd) instar H. virescens (r = 0.979) and P. interpunctella (r = 0.930). Second instar Biobit—exposed P. interpunctella had 10 times more PO activity than unexposed larvae. Similarly, the amount of total protein was lower in 4(th) instar Biobit—exposed H. virescens and higher in S. exigua. Therefore, the results indicated a relationship between Biobit susceptibility and PO activity in some cases. This information may be useful if the Biobit application period is timed for a developmental stage with low PO activity. However, more studies are needed to determine the correlation of each insect with a particular bioinsecticide. University of Wisconsin Library 2012-07-12 /pmc/articles/PMC3593704/ /pubmed/23414117 http://dx.doi.org/10.1673/031.012.8001 Text en © 2012 http://creativecommons.org/licenses/by/2.5/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Article Valadez-Lira, J.A. Alcocer-Gonzalez, J.M. Damas, G. Nuñez-Mejía, G. Oppert, B. Rodriguez-Padilla, C. Tamez-Guerra, P. Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis |
title | Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis
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title_full | Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis
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title_fullStr | Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis
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title_full_unstemmed | Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis
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title_short | Comparative Evaluation of Phenoloxidase Activity in Different Larval Stages of Four Lepidopteran Pests After Exposure to Bacillus thuringiensis
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title_sort | comparative evaluation of phenoloxidase activity in different larval stages of four lepidopteran pests after exposure to bacillus thuringiensis |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3593704/ https://www.ncbi.nlm.nih.gov/pubmed/23414117 http://dx.doi.org/10.1673/031.012.8001 |
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