The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i>
<i>Bacillus thuringiensis</i> (Bt) has been extensively applied in agricultural pest management, posing a notable ecological risk to beneficial insects like <i>Bombyx mori</i> (silkworms). However, the toxicological mechanisms of Bt at low concentrations on silkworms remain l...
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2024-11-01
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| author | Hongbin Zou Haoyi Gu Jialu Cheng Chao Tian Qilong Shu Peilin Peng Bing Li |
| author_facet | Hongbin Zou Haoyi Gu Jialu Cheng Chao Tian Qilong Shu Peilin Peng Bing Li |
| author_sort | Hongbin Zou |
| collection | DOAJ |
| description | <i>Bacillus thuringiensis</i> (Bt) has been extensively applied in agricultural pest management, posing a notable ecological risk to beneficial insects like <i>Bombyx mori</i> (silkworms). However, the toxicological mechanisms of Bt at low concentrations on silkworms remain largely unexplored. In this study, we determined the <i>LC</i><sub>50</sub> (96 h) of Bt for fifth-instar silkworm larvae to be 0.08 × 10<sup>−3</sup> mg/L. Exposure to a sub-lethal concentration of Bt (1/2 <i>LC</i><sub>50</sub>) led to significant reductions in body weight, pupal size, and the weights of both the whole cocoon and cocoon shell. Histopathological and ultrastructural examinations revealed that Bt exposure caused severe damage to the microvilli and epidermal cells of the midgut. Transcriptome sequencing of the midgut identified 290 differentially expressed genes (DEGs), with these genes predominantly involved in metabolic processes and apoptotic pathways. Notably, apoptosis-related genes such as <i>Apaf-1</i> and <i>Caspase-3</i> were upregulated by 5.08-fold and 1.27-fold, respectively. Further validation through TUNEL assays and Western blotting analysis confirmed a significant activation of apoptotic signaling. These findings suggested that low concentrations of Bt could trigger apoptotic pathways in the midgut of silkworm larvae, providing valuable insights into the toxicological evaluation of Bt at sub-lethal doses in insect species. |
| format | Article |
| id | doaj-art-0c334800a8c64dbba37d40f73c09e67b |
| institution | Kabale University |
| issn | 2075-4450 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | MDPI AG |
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| series | Insects |
| spelling | doaj-art-0c334800a8c64dbba37d40f73c09e67b2024-12-27T14:31:09ZengMDPI AGInsects2075-44502024-11-01151291110.3390/insects15120911The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i>Hongbin Zou0Haoyi Gu1Jialu Cheng2Chao Tian3Qilong Shu4Peilin Peng5Bing Li6School of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, ChinaSchool of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, ChinaSchool of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, ChinaSchool of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, ChinaSchool of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, ChinaSchool of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, ChinaSchool of Life Sciences, Suzhou Medical College, Soochow University, Suzhou 215006, China<i>Bacillus thuringiensis</i> (Bt) has been extensively applied in agricultural pest management, posing a notable ecological risk to beneficial insects like <i>Bombyx mori</i> (silkworms). However, the toxicological mechanisms of Bt at low concentrations on silkworms remain largely unexplored. In this study, we determined the <i>LC</i><sub>50</sub> (96 h) of Bt for fifth-instar silkworm larvae to be 0.08 × 10<sup>−3</sup> mg/L. Exposure to a sub-lethal concentration of Bt (1/2 <i>LC</i><sub>50</sub>) led to significant reductions in body weight, pupal size, and the weights of both the whole cocoon and cocoon shell. Histopathological and ultrastructural examinations revealed that Bt exposure caused severe damage to the microvilli and epidermal cells of the midgut. Transcriptome sequencing of the midgut identified 290 differentially expressed genes (DEGs), with these genes predominantly involved in metabolic processes and apoptotic pathways. Notably, apoptosis-related genes such as <i>Apaf-1</i> and <i>Caspase-3</i> were upregulated by 5.08-fold and 1.27-fold, respectively. Further validation through TUNEL assays and Western blotting analysis confirmed a significant activation of apoptotic signaling. These findings suggested that low concentrations of Bt could trigger apoptotic pathways in the midgut of silkworm larvae, providing valuable insights into the toxicological evaluation of Bt at sub-lethal doses in insect species.https://www.mdpi.com/2075-4450/15/12/911<i>Bombyx mori</i><i>Bacillus thuringiensis</i>midgutapoptosistranscriptome analysis |
| spellingShingle | Hongbin Zou Haoyi Gu Jialu Cheng Chao Tian Qilong Shu Peilin Peng Bing Li The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i> Insects <i>Bombyx mori</i> <i>Bacillus thuringiensis</i> midgut apoptosis transcriptome analysis |
| title | The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i> |
| title_full | The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i> |
| title_fullStr | The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i> |
| title_full_unstemmed | The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i> |
| title_short | The Mechanism of Damage to the Midgut by Low Concentration of <i>Bacillus thuringiensis</i> in the Silkworm, <i>Bombyx mori</i> |
| title_sort | mechanism of damage to the midgut by low concentration of i bacillus thuringiensis i in the silkworm i bombyx mori i |
| topic | <i>Bombyx mori</i> <i>Bacillus thuringiensis</i> midgut apoptosis transcriptome analysis |
| url | https://www.mdpi.com/2075-4450/15/12/911 |
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