1
|
Chen F, Pang C, Zheng Z, Zhou W, Guo Z, Xiao D, Du H, Bravo A, Soberón M, Sun M, Peng D. Aminopeptidase MNP-1 triggers intestine protease production by activating daf-16 nuclear location to degrade pore-forming toxins in Caenorhabditis elegans. PLoS Pathog 2023; 19:e1011507. [PMID: 37440595 PMCID: PMC10368266 DOI: 10.1371/journal.ppat.1011507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Pore-forming toxins (PFTs) are effective tools for pathogens infection. By disrupting epithelial barriers and killing immune cells, PFTs promotes the colonization and reproduction of pathogenic microorganisms in their host. In turn, the host triggers defense responses, such as endocytosis, exocytosis, or autophagy. Bacillus thuringiensis (Bt) bacteria produce PFT, known as crystal proteins (Cry) which damage the intestinal cells of insects or nematodes, eventually killing them. In insects, aminopeptidase N (APN) has been shown to act as an important receptor for Cry toxins. Here, using the nematode Caenorhabditis elegans as model, an extensive screening of APN gene family was performed to analyze the potential role of these proteins in the mode of action of Cry5Ba against the nematode. We found that one APN, MNP-1, participate in the toxin defense response, since the mnp-1(ok2434) mutant showed a Cry5Ba hypersensitive phenotype. Gene expression analysis in mnp-1(ok2434) mutant revealed the involvement of two protease genes, F19C6.4 and R03G8.6, that participate in Cry5Ba degradation. Finally, analysis of the transduction pathway involved in F19C6.4 and R03G8.6 expression revealed that upon Cry5Ba exposure, the worms up regulated both protease genes through the activation of the FOXO transcription factor DAF-16, which was translocated into the nucleus. The nuclear location of DAF-16 was found to be dependent on mnp-1 under Cry5Ba treatment. Our work provides evidence of new host responses against PFTs produced by an enteric pathogenic bacterium, resulting in activation of host intestinal proteases that degrade the PFT in the intestine.
Collapse
Affiliation(s)
- Feng Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Cuiyun Pang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Ziqiang Zheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Wei Zhou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Zhiqing Guo
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Danyang Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Hongwen Du
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| |
Collapse
|
2
|
Peña-Rico MA, Bravo-D HR, Roldan-Sabino C, Castro-Cerritos KV, Huerta-Heredia A, Navarro-Mtz AK. Addition of proteinase K during the culture alter the physiology of Bacillus thuringiensis culture and the cry1Ac, nprX, nprA, and spo0A gene transcription. Antonie van Leeuwenhoek 2021; 115:89-102. [PMID: 34797466 DOI: 10.1007/s10482-021-01683-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/03/2021] [Indexed: 11/30/2022]
Abstract
Bacillus thuringiensis is the major bioinsecticide worldwide produced due to the Cry protein activity. Several studies have been done to improve the cost-productivity relation. The neutral protease A (NprA) is the major extracellular protein massively produced during the stationary phase by this bacterium, contributing to the Cry proteins' degradation. Also, the deletion of aprA and nprA genes enhanced the yield of Cry protein, stabilizing it. Therefore, to increase Cry production, one possibility is to degrade the NprA protease in the culture media. In the present study, proteinase K was used to hydrolyze the NprA to increase Cry production. Proteinase K was added during the exponential growth of B. thuringiensis culture. The bacilli and endospores were measured along all culture, while the Cry protein was measured at the end of the culture. The addition of PK affects the bacilli and spore kinetics positively but negatively to the Cry protein (there is no Cry protein detection). Therefore, the gene expression of the cry1Ac, nprX, nprA, and spo0A was measured. The expression of each gene was followed along all culture. Results demonstrated that PK alters both the transcriptional levels and the expression order of the genes.
Collapse
Affiliation(s)
- Miguel A Peña-Rico
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Humberto R Bravo-D
- División de Estudios de Posgrado, Doctorado en Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Crisanto Roldan-Sabino
- Ingeniería en Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Karla V Castro-Cerritos
- Instituto de Química Aplicada, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Ariana Huerta-Heredia
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México.,CONACyT-UNPA, Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - A Karin Navarro-Mtz
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México.
| |
Collapse
|
3
|
Nematicidal and ovicidal activity of Bacillus thuringiensis against the zoonotic nematode Ancylostoma caninum. Exp Parasitol 2020; 218:107982. [PMID: 32866584 DOI: 10.1016/j.exppara.2020.107982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 07/02/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022]
Abstract
Ancylostoma caninum is a gastrointestinal parasite that affect dogs and humans, considered a worldwide public health problem. The control of these parasitosis is increasingly difficult due to the development of multi-drug resistance. Bacillus thuringiensis is an insecticidal, spore forming bacterium, often species specific. The strain GP526 of B. thuringiensis has toxic effect on the cestode Dipylidium caninum and the trematode Centrocestus formosanus, both of them zoonotic parasites. The high degrees of specificity and environment safe make B. thuringiensis suitable for use against pathogen parasites, especially those resistant to synthetic chemical insecticides. The objective of the current work was to evaluate the in vitro effect of B. thuringiensis on Ancylostoma caninum. Spore-crystal mixture of the strains was co-incubated with 120 adult nematodes (males, non-pregnant females and pregnant females) or with 4800 eggs. GP526 showed a nematicidal effect with an LT50 of 35.8 h and an LC50 of 60 μg/ml. It also showed an ovicidal effect with an LC50 of 94.9 μg/ml. Histological analyses showed detachment of the cuticle and of the uterus in adult females, and vacuolization with destruction of the eggs. The effects of GP526 strain were comparable to those of albendazole, allowing us to propose GP526 for A. caninum control, in both, the adult stage at a gastrointestinal level, and in egg stage in the environment. In addition, GP526 can be proposed as a potential broad spectrum antiparasitic drug.
Collapse
|
4
|
Shen J, Hu L, Dai J, Chen B, Zhong G, Zhou X. Mutations in pheromone-binding protein3 contribute to pheromone response variations in Plutella xylostella (L.) (Lepidoptera: Plutellidae). PEST MANAGEMENT SCIENCE 2019; 75:2034-2042. [PMID: 30624018 DOI: 10.1002/ps.5325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 10/23/2018] [Accepted: 12/10/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) is one of the most important crucifer pests. Commercial sex attractants have been developed to monitor and control P. xylostella. However, some studies have demonstrated a variety of pheromone responses of P. xylostella in different locations of the world. Soluble pheromone-binding proteins (PBPs), as a subfamily of odorant-binding proteins (OBPs), could selectively bind and transport pheromones across aqueous sensillar lymph to the surface of olfactory receptor neurons. It is worthy to study whether the mutation of PxylPBPs is one of the reasons for the different responses of sex attractors in different regions. RESULTS In this study, P. xylostella males were collected from seven Chinese provinces, including Hainan, Guangdong, Yunnan, Fujian, Hunan, Zhejiang, and Hebei. PxylPBP1, PxylPBP2, and PxylPBP3 were cloned, and 3, 6, and 32 types of mutation pattern were identified, respectively. These mutation patterns were distributed in each province with different frequency. The results of fluorescence displacement binding assay and in silico simulation revealed that the three mutant PxylPBP3 were more sensitive to Z11-16:Ald than the reference protein (ACI28451). CONCLUSION This result implied that mutation of PxylPBP3 may have contributed to regional differences in pheromone responses of P. xylostella. © 2019 Society of Chemical Industry.
Collapse
Affiliation(s)
- Jianmei Shen
- College of Agriculture and Biology, ZhongKai University of Agriculture and Engineering, Guangzhou, China
| | - Liming Hu
- College of Agriculture and Biology, ZhongKai University of Agriculture and Engineering, Guangzhou, China
| | - Jianqing Dai
- Guangdong Institute of Applied Biological Resources, Guangzhou, China
| | - Binghan Chen
- College of Agriculture and Biology, ZhongKai University of Agriculture and Engineering, Guangzhou, China
| | - Guohua Zhong
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Xinhua Zhou
- College of Chemistry and Chemical Engineering, ZhongKai University of Agriculture and Engineering, Guangzhou, China
| |
Collapse
|
5
|
Li R, Yang S, Qiu X, Lu X, Hu Q, Ren X, Wu B, Qi L, Ding X, Xia L, Sun Y. The conserved cysteine residues in Bacillus thuringiensis Cry1Ac protoxin are not essential for the bipyramidal crystal formation. J Invertebr Pathol 2019; 163:82-85. [PMID: 30928458 DOI: 10.1016/j.jip.2019.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/20/2019] [Accepted: 03/27/2019] [Indexed: 11/19/2022]
Abstract
To evaluate the function of conserved cysteine residues in Cry1Ac protoxin, we constructed a series of Cry1Ac mutants in which single or multiple cysteine residues were replaced with serine. It was found that cysteine substitution had little effect on the protoxin expression and bipyramidal crystal formation. Bioassays using Plutella xylostella larvae showed that two mutants with fourteen cysteine residues in the C-terminal half and all sixteen residues replaced had similar toxicity as wildtype Cry1Ac protoxin. Our study suggests that the conserved cysteine resudues in the Cry1Ac protoxin are not essential for deposition into a bipyramidal crystal even though the C-terminal half was directly involved in crystal formation.
Collapse
Affiliation(s)
- Ran Li
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Sisi Yang
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Xianfeng Qiu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Xiuqing Lu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Quanfang Hu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Xiaomeng Ren
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Binbin Wu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Lingling Qi
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Xuezhi Ding
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Liqiu Xia
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China
| | - Yunjun Sun
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China.
| |
Collapse
|
6
|
Wan L, Lin J, Du H, Zhang Y, Bravo A, Soberón M, Sun M, Peng D. Bacillus thuringiensistargets the host intestinal epithelial junctions for successful infection ofCaenorhabditis elegans. Environ Microbiol 2019; 21:1086-1098. [DOI: 10.1111/1462-2920.14528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/02/2018] [Accepted: 12/12/2018] [Indexed: 01/28/2023]
Affiliation(s)
- Liting Wan
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Jian Lin
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Hongwen Du
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Yulan Zhang
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Alejandra Bravo
- Instituto de BiotecnologíaUniversidad Nacional Autónoma de México Apdo. postal 510‐3, Cuernavaca, 62250 Morelos Mexico
| | - Mario Soberón
- Instituto de BiotecnologíaUniversidad Nacional Autónoma de México Apdo. postal 510‐3, Cuernavaca, 62250 Morelos Mexico
| | - Ming Sun
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Donghai Peng
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| |
Collapse
|
7
|
Qiu X, Lu X, Ren X, Li R, Wu B, Yang S, Qi L, Mo X, Ding X, Xia L, Sun Y. Solubility enhancement of Cry2Aa crystal through carboxy-terminal extension and synergism between the chimeric protein and Cry1Ac. Appl Microbiol Biotechnol 2019; 103:2243-2250. [PMID: 30617818 DOI: 10.1007/s00253-018-09606-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 11/26/2022]
Abstract
It was reported that the highly conserved C-terminal region of Bacillus thuringiensis Cry1A protoxins was very important for parasporal crystal formation and solubility feature in alkaline environment. In order to improve the solubilization efficiency of Cry2Aa crystal, the coding sequences of Cry2Aa protein and the C-terminal half of Cry1Ac were fused seamlessly through Red/ET homologous recombination and expressed in an acrystalliferous B. thuringiensis strain under the control of the cry1Ac promoter and terminator. Microscopic observation revealed that the recombinant strain containing the chimeric gene cry2Aa-1Ac produced distinct parasporal inclusion with semispherical to approximately cuboidal shape during sporulation. SDS-PAGE analysis showed that this strain expressed stable 130-kDa Cry2Aa-1Ac chimeric protein, which was confirmed to be the correctly expressed product by LC-MS/MS. The chimeric protein inclusion could be effectively dissolved at pH 10.5 and activated by trypsin like the parental Cry1Ac crystal. While, the parental Cry2Aa crystal exhibited very low solubility under this condition. Bioassays against third-instar larvae of Helicoverpa armigera proved that the chimeric protein was more toxic than Cry2Aa. Additionally, synergistic effect was clearly detected between the chimeric protein and Cry1Ac against H. armigera, while there was only additive effect for the combination of wild Cry2Aa and Cry1Ac. These results indicated that the developed chimeric protein might serve as a potent insecticidal toxin used in the field against lepidopteran pests.
Collapse
Affiliation(s)
- Xianfeng Qiu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Xiuqing Lu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Xiaomeng Ren
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Ran Li
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Binbin Wu
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Sisi Yang
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Lingling Qi
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Xiangtao Mo
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Xuezhi Ding
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Liqiu Xia
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China
| | - Yunjun Sun
- College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, People's Republic of China.
| |
Collapse
|
8
|
Fu Y, Wu Y, Yuan Y, Gao M. Complete Genome Sequence of Bacillus thuringiensis Serovar rongseni Reference Strain SCG04-02, a Strain Toxic to Plutella xylostella. GENOME ANNOUNCEMENTS 2017; 5:e00691-17. [PMID: 28963199 PMCID: PMC5624745 DOI: 10.1128/genomea.00691-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 06/08/2017] [Indexed: 11/21/2022]
Abstract
Bacillus thuringiensis (Bt) is widely used to control agricultural and forestry pests, though there are only a few available complete genome sequences of the Bt reference strain. Here, we report the complete genome sequence of B. thuringiensis serovar rongseni reference strain SCG04-02, which is toxic to Plutella xylostella.
Collapse
Affiliation(s)
- Yajuan Fu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Huaibeizhen, Huairou, Beijing, China
| | - Yan Wu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yihui Yuan
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Meiying Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| |
Collapse
|
9
|
Seid CA, Jones KM, Pollet J, Keegan B, Hudspeth E, Hammond M, Wei J, McAtee CP, Versteeg L, Gutierrez A, Liu Z, Zhan B, Respress JL, Strych U, Bottazzi ME, Hotez PJ. Cysteine mutagenesis improves the production without abrogating antigenicity of a recombinant protein vaccine candidate for human chagas disease. Hum Vaccin Immunother 2016; 13:621-633. [PMID: 27737611 DOI: 10.1080/21645515.2016.1242540] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A therapeutic vaccine for human Chagas disease is under development by the Sabin Vaccine Institute Product Development Partnership. The aim of the vaccine is to significantly reduce the parasite burden of Trypanosoma cruzi in humans, either as a standalone product or in combination with conventional chemotherapy. Vaccination of mice with Tc24 formulated with monophosphoryl-lipid A (MPLA) adjuvant results in a Th1 skewed immune response with elevated IgG2a and IFNγ levels and a statistically significant decrease in parasitemia following T. cruzi challenge. Tc24 was therefore selected for scale-up and further evaluation. During scale up and downstream process development, significant protein aggregation was observed due to intermolecular disulfide bond formation. To prevent protein aggregation, cysteine codons were replaced with serine codons which resulted in the production of a non-aggregated and soluble recombinant protein, Tc24-C4. No changes to the secondary structure of the modified molecule were detected by circular dichroism. Immunization of mice with wild-type Tc24 or Tc24-C4, formulated with E6020 (TLR4 agonist analog to MPLA) emulsified in a squalene-oil-in-water emulsion, resulted in IgG2a and antigen specific IFNγ production levels from splenocytes that were not significantly different, indicating that eliminating putative intermolecular disulfide bonds had no significant impact on the immunogenicity of the molecule. In addition, vaccination with either formulated wild type Tc24 or Tc24-C4 antigen also significantly increased survival and reduced cardiac parasite burden in mice. Investigations are now underway to examine the efficacy of Tc24-C4 formulated with other adjuvants to reduce parasite burden and increase survival in pre-clinical studies.
Collapse
Affiliation(s)
- Christopher A Seid
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Kathryn M Jones
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Jeroen Pollet
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Brian Keegan
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Elissa Hudspeth
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Molly Hammond
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Junfei Wei
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - C Patrick McAtee
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Leroy Versteeg
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Amanda Gutierrez
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Zhuyun Liu
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Bin Zhan
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Jonathan L Respress
- d Southwest Electronic Energy Medical Research Institute (SWEMRI) , Missouri City , TX , USA
| | - Ulrich Strych
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Maria Elena Bottazzi
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Peter J Hotez
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA.,c James A. Baker III Institute for Public Policy , Rice University , Houston , TX , USA
| |
Collapse
|
10
|
Peng D, Lin J, Huang Q, Zheng W, Liu G, Zheng J, Zhu L, Sun M. A novel metalloproteinase virulence factor is involved in Bacillus thuringiensis pathogenesis in nematodes and insects. Environ Microbiol 2015; 18:846-62. [PMID: 26995589 DOI: 10.1111/1462-2920.13069] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/25/2015] [Indexed: 11/29/2022]
Abstract
The Gram-positive soil bacterium Bacillus thuringiensis has been developed as the leading microbial insecticide for years. The pathogenesis of B. thuringiensis requires common extracellular factors that depend on the PlcR regulon, which regulates a large number of virulence factors; however, the precise role of many of these proteins is not known. In this study, we describe the complete lifecycle of a nematicidal B. thuringiensis strain in the free living nematode Caenorhabditis elegans using in vitro and in vivo molecular techniques to follow host and bacterial effectors during the infection process. We then focus on the metalloproteinase ColB, a collagenase, which was found highly important for destruction of the intestine thereby facilitates the adaptation and colonization of B. thuringiensis in C. elegans. In vivo green fluorescent protein (GFP) reporter-gene studies showed that ColB expression is highly induced and regulated by the global activator PlcR. Finally, we demonstrated that ColB also takes part in B. thuringiensis virulence in an insect model following injection and oral infection. Indeed, addition of purified ColB accelerates the action of Cry toxin proteins in insects, too. These results give novel insights into host adaptation for B. thuringiensis and other B. cereus group bacteria and highlight the role of collagenase metalloproteases to synergize infection process.
Collapse
Affiliation(s)
- Donghai Peng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jian Lin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiong Huang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wen Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Guoqiang Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Lei Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| |
Collapse
|
11
|
The expression and crystallization of Cry65Aa require two C-termini, revealing a novel evolutionary strategy of Bacillus thuringiensis Cry proteins. Sci Rep 2015; 5:8291. [PMID: 25656389 PMCID: PMC4319155 DOI: 10.1038/srep08291] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/14/2015] [Indexed: 11/11/2022] Open
Abstract
The insecticidal crystal protein (Cry) genes of Bacillus thuringiensis are a key gene resource for generating transgenic crops with pest resistance. However, many cry genes cannot be expressed or form crystals in mother cells. Here, we report a novel Cry protein gene, cry65Aa1, which exists in an operon that contains a downstream gene encoding a hypothetical protein ORF2. We demonstrated that ORF2 is required for Cry65Aa1 expression and crystallization by function as a C-terminal crystallization domain. The orf2 sequence is also required for Cry65Aa expression, because orf2 transcripts have a stabilizing effect on cry65Aa1 transcripts. Furthermore, we found that the crystallization of Cry65Aa1 required the Cry65Aa1 C-terminus in addition to ORF2 or a typical Cry protein C-terminal region. Finally, we showed that Cry65Aa1 has a selective cytotoxic effect on MDA-MB231 cancer cells. This report is the first description of a 130-kDa mass range Cry protein requiring two C-termini for crystallization. Our findings reveal a novel evolutionary strategy of Cry proteins and provide an explanation for the existence of Cry protein genes that cannot form crystals in B. thuringiensis. This study also provides a potential framework for isolating novel cry genes from “no crystal” B. thuringiensis strains.
Collapse
|
12
|
Efficient production of Bacillus thuringiensis Cry1AMod toxins under regulation of cry3Aa promoter and single cysteine mutations in the protoxin region. Appl Environ Microbiol 2013; 79:6969-73. [PMID: 24014526 DOI: 10.1128/aem.02546-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus thuringiensis Cry1AbMod toxins are engineered versions of Cry1Ab that lack the amino-terminal end, including domain I helix α-1 and part of helix α-2. This deletion improves oligomerization of these toxins in solution in the absence of cadherin receptor and counters resistance to Cry1A toxins in different lepidopteran insects, suggesting that oligomerization plays a major role in their toxicity. However, Cry1AbMod toxins are toxic to Escherichia coli cells, since the cry1A promoter that drives its expression in B. thuringiensis has readthrough expression activity in E. coli, making difficult the construction of these CryMod toxins. In this work, we show that Cry1AbMod and Cry1AcMod toxins can be cloned efficiently under regulation of the cry3A promoter region to drive its expression in B. thuringiensis without expression in E. coli cells. However, p3A-Cry1Ab(c)Mod construction promotes the formation of Cry1AMod crystals in B. thuringiensis cells that were not soluble at pH 10.5 and showed no toxicity to Plutella xylostella larvae. Cysteine residues in the protoxin carboxyl-terminal end of Cry1A toxins have been shown to be involved in disulfide bond formation, which is important for crystallization. Six individual cysteine substitutions for serine residues were constructed in the carboxyl-terminal protoxin end of the p3A-Cry1AbMod construct and one in the carboxyl-terminal protoxin end of p3A-Cry1AcMod. Interestingly, p3A-Cry1AbMod C654S and C729S and p3A-Cry1AcMod C730S recover crystal solubility at pH 10.5 and toxicity to P. xylostella. These results show that combining the cry3A promoter expression system with single cysteine mutations is a useful system for efficient expression of Cry1AMod toxins in B. thuringiensis.
Collapse
|
13
|
Ser-substituted mutations of Cys residues in Bacillus thuringiensis Vip3Aa7 exert a negative effect on its insecticidal activity. Curr Microbiol 2012; 65:583-8. [PMID: 22875104 DOI: 10.1007/s00284-012-0201-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Accepted: 06/22/2012] [Indexed: 01/25/2023]
Abstract
Vegetative insecticidal proteins (VIPs), which were produced by Bacillus thuringiensis during its vegetative growth stage, display a broad insecticidal spectrum to Lepidoptera larvae. Sequence alignment of the Vip3A-type indicates that three cysteine residues were conserved in Vip3A-type proteins. To determine whether these conserved cysteine residues contributed to the insecticidal activity, the three residues were respectively substituted with serine in the Vip3Aa7 protein by site-directed mutagenesis. Bioassays using the third instar larvae of Plutella xylostella showed that the toxicity of C401S and C507S mutants were completely abolished. To find out the inactivity reason of mutants, three mutants and the wild-type Vip3Aa7 were treated with trypsin. The results indicated that the C507S mutant was rapidly cleaved and resulted in decrease of the 62 kDa toxic core fragment. These results indicated that the replacement of the Cys(507) with a Ser(507) caused decrease in C507S resistance against trypsin degradation. It is suggesting a possible association between insecticidal activity and trypsin sensitivity of Vip3A proteins. This study serves a guideline for the study of Vip3A protein structure and active mechanism.
Collapse
|
14
|
Improvement of crystal solubility and increasing toxicity against Caenorhabditis elegans by asparagine substitution in block 3 of Bacillus thuringiensis crystal protein Cry5Ba. Appl Environ Microbiol 2012; 78:7197-204. [PMID: 22865071 DOI: 10.1128/aem.01048-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The crystal proteins from Bacillus thuringiensis are widely used for their specific toxicity against insects and nematodes. The highly conserved sequence blocks play an important role in Cry protein stability and flexibility, the basis of toxicity. The block 3 in Cry5Ba subfamily has a shorter sequence (only 12 residues) and more asparagine residues than that of others which harbor about 48 residues but only one asparagine. Based on the theoretical structure model of Cry5Ba, all three asparagines in block 3 are closely located in the interface of putative three domains, implying their probable importance in structure and function. In this study, all three asparagines in Cry5Ba2 block 3 were individually substituted with alanine by site-directed mutagenesis. The wild-type and mutant proteins were overexpressed and crystallized in acrystalliferous B. thuringiensis strain BMB171. However, the crystals formed in one of the mutants, designated N586A, abnormally disappeared and dissolved into the culture supernatant once the sporulation cells lysed, whereas the Cry5Ba crystal and the other mutant crystals were stable. The mutant N586A crystal, isolated from sporulation cells by the ultrasonic process, was found to be easily dissolved at wide range of pH value (5.0 to 10.0). Moreover, the toxicity assays showed that the mutant N586A exhibited nearly 9-fold-higher activity against nematodes and damaged the host's intestine more efficiently than the native Cry5Ba2. These data support the presumption that the amide residue Asn586 at the interface of domains might adversely affect the protein flexibility, solubility and resultant toxicity of Cry5Ba.
Collapse
|
15
|
Song P, Wang Q, Nangong Z, Su J, Ge D. Identification of Henosepilachna vigintioctomaculata (Coleoptera: Coccinellidae) midgut putative receptor for Bacillus thuringiensis insecticidal Cry7Ab3 toxin. J Invertebr Pathol 2012; 109:318-22. [DOI: 10.1016/j.jip.2012.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/11/2012] [Accepted: 01/21/2012] [Indexed: 11/29/2022]
|