scholarly journals A Bacillus thuringiensis S-Layer Protein Involved in Toxicity against Epilachna varivestis (Coleoptera: Coccinellidae)

2006 ◽  
Vol 72 (1) ◽  
pp. 353-360 ◽  
Author(s):  
Guadalupe Peña ◽  
Juan Miranda-Rios ◽  
Gustavo de la Riva ◽  
Liliana Pardo-López ◽  
Mario Soberón ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Pathogenic Bacteria ◽  
Bacillus Sphaericus ◽  
Epilachna Varivestis ◽  
Gene Encoding ◽  
Parasporal Crystal ◽  
Cry Proteins ◽  
Bean Beetle ◽  
Paracrystalline Array

ABSTRACT The use of Bacillus thuringiensis as a biopesticide is a viable alternative for insect control since the insecticidal Cry proteins produced by these bacteria are highly specific; harmless to humans, vertebrates, and plants; and completely biodegradable. In addition to Cry proteins, B. thuringiensis produces a number of extracellular compounds, including S-layer proteins (SLP), that contribute to virulence. The S layer is an ordered structure representing a proteinaceous paracrystalline array which completely covers the surfaces of many pathogenic bacteria. In this work, we report the identification of an S-layer protein by the screening of B. thuringiensis strains for activity against the coleopteran pest Epilachna varivestis (Mexican bean beetle; Coleoptera: Coccinellidae). We screened two B. thuringiensis strain collections containing unidentified Cry proteins and also strains isolated from dead insects. Some of the B. thuringiensis strains assayed against E. varivestis showed moderate toxicity. However, a B. thuringiensis strain (GP1) that was isolated from a dead insect showed a remarkably high insecticidal activity. The parasporal crystal produced by the GP1 strain was purified and shown to have insecticidal activity against E. varivestis but not against the lepidopteran Manduca sexta or Spodoptera frugiperda or against the dipteran Aedes aegypti. The gene encoding this protein was cloned and sequenced. It corresponded to an S-layer protein highly similar to previously described SLP in Bacillus anthracis (EA1) and Bacillus licheniformis (OlpA). The phylogenetic relationships among SLP from different bacteria showed that these proteins from Bacillus cereus, Bacillus sphaericus, B. anthracis, B. licheniformis, and B. thuringiensis are arranged in the same main group, suggesting similar origins. This is the first report that demonstrates that an S-layer protein is directly involved in toxicity to a coleopteran pest.

The Introduction into Bacillus sphaericus of the Bacillus thuringiensis subsp. medellin cyt1Ab1 Gene Results in Higher Susceptibility of Resistant Mosquito Larva Populations to B. sphaericus

1998 ◽  
Vol 64 (10) ◽  
pp. 3910-3916 ◽  
Author(s):  
I. Thiéry ◽  
S. Hamon ◽  
A. Delécluse ◽  
S. Orduz
Keyword(s):  
Bacillus Thuringiensis ◽  
Culex Pipiens ◽  
Recombinant Strain ◽  
Mosquito Larva ◽  
Shuttle Vector ◽  
Bacillus Sphaericus ◽  
The Other ◽  
Binary Toxin ◽  
Gene Encoding ◽  
Flanking Sequences

ABSTRACT The fragment containing the gene encoding the cytolytic Cyt1Ab1 protein from Bacillus thuringiensis subsp.medellin and its flanking sequences (I. Thiery, A. Delécluse, M. C. Tamayo, and S. Orduz, Appl. Environ. Microbiol. 63:468–473, 1997) was introduced into Bacillus sphaericus toxic strains 2362, 2297, and Iab872 by electroporation with the shuttle vector pMK3. Only small amounts of the protein were produced in recombinant strains 2362 and Iab872. The protein was detected in these strains only by Western blotting and immunodetection with antibody raised against Cyt1Ab1 protein. Large amounts of Cyt1Ab1 protein were produced in B. sphaericus recombinant strain 2297, and there was an additional crystal, other than that of the binary toxin, within the exosporium. The production of the Cyt1Ab1 protein in addition to the binary toxin did not increase the larvicidal activity of theB. sphaericus recombinant strain against susceptible mosquito populations of Culex pipiens orAedes aegypti. However, it partially restored (10 to 20 times) susceptibility of the resistant mosquito populations of C. pipiens (SPHAE) and Culex quinquefasciatus (GeoR) to the binary toxin. The Cyt1Ab1 protein produced in recombinantB. thuringiensis SPL407(pcyt1Ab1) was synthesized in two types of crystal—one round and with various dense areas, surrounded by an envelope, and the other a regular cuboid crystal, very similar to that found in the B. sphaericus recombinant strain.

scholarly journals Improving the Insecticidal Activity against Resistant Culex quinquefasciatus Mosquitoes by Expression of Chitinase Gene chiAC in Bacillus sphaericus

2007 ◽  
Vol 73 (23) ◽  
pp. 7744-7746 ◽  
Author(s):  
Yajun Cai ◽  
Jianpin Yan ◽  
Xiaomin Hu ◽  
Bei Han ◽  
Zhiming Yuan
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Culex Quinquefasciatus ◽  
Recombinant Strain ◽  
Bacillus Sphaericus ◽  
Chitinase Gene ◽  
Binary Toxin

ABSTRACT Expression of a chitinase gene, chiAC, from Bacillus thuringiensis in B. sphaericus 2297 using the binary toxin promoter yielded a recombinant strain that was 4,297-fold more toxic than strain 2297 against resistant Culex quinquefasciatus. These results show that this chitinase can synergize the toxicity of the binary toxin against mosquitoes and thus may be useful in managing mosquito resistance to B. sphaericus.

scholarly journals Insecticidal Activity of Bacillus thuringiensis Proteins against Coleopteran Pests

Toxins ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 430 ◽  
Author(s):  
Mikel Domínguez-Arrizabalaga ◽  
Maite Villanueva ◽  
Baltasar Escriche ◽  
Carmen Ancín-Azpilicueta ◽  
Primitivo Caballero
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Mode Of Action ◽  
Insect Species ◽  
Specific Information ◽  
Cry Proteins ◽  
Microbial Insecticide ◽  
Bt Toxins ◽  
Vip Proteins ◽  
Agro Forestry

Bacillus thuringiensis is the most successful microbial insecticide agent and its proteins have been studied for many years due to its toxicity against insects mainly belonging to the orders Lepidoptera, Diptera and Coleoptera, which are pests of agro-forestry and medical-veterinary interest. However, studies on the interactions between this bacterium and the insect species classified in the order Coleoptera are more limited when compared to other insect orders. To date, 45 Cry proteins, 2 Cyt proteins, 11 Vip proteins, and 2 Sip proteins have been reported with activity against coleopteran species. A number of these proteins have been successfully used in some insecticidal formulations and in the construction of transgenic crops to provide protection against main beetle pests. In this review, we provide an update on the activity of Bt toxins against coleopteran insects, as well as specific information about the structure and mode of action of coleopteran Bt proteins.

scholarly journals Induced-feeding bioassays for detection of Bacillus thuringiensis insecticidal activity against Epilachna paenulata (Coleoptera)

2010 ◽  
Vol 45 (4) ◽  
pp. 430-432
Author(s):  
Diego Herman Sauka ◽  
Rodrigo Horacio Monella ◽  
Graciela Beatriz Benintende
Keyword(s):  
Bacillus Thuringiensis ◽  
Pest Control ◽  
Insecticidal Activity ◽  
Great Majority ◽  
Cry Proteins ◽  
Feeding Bioassay ◽  
High Concentrations ◽  
Epilachna Paenulata

The objective of this work was to establish and test the induced-feeding bioassay in order to detect Bacillus thuringiensis insecticidal activity against Epilachna paenulata (Coleoptera: Coccinellidae). Larvae were induced to swallow high concentrations of spore-crystal suspensions of seven exotic and 30 Argentine B. thuringiensis strains. The great majority of strains showed no toxicity to E. paenulata larvae, and observed mortality was lower than 30%. Induced-feeding bioassay is feasible, and should be used for prospecting strains that produce right combinations of Cry proteins needed to an efficient pest control.

scholarly journals Insect Hsp90 Chaperone Assists Bacillus thuringiensis Cry Toxicity by Enhancing Protoxin Binding to the Receptor and by Protecting Protoxin from Gut Protease Degradation

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Blanca I. García-Gómez ◽  
Sayra N. Cano ◽  
Erika E. Zagal ◽  
Edgar Dantán-Gonzalez ◽  
Alejandra Bravo ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Receptor Binding ◽  
Insecticidal Activity ◽  
Insect Pests ◽  
Biotechnological Applications ◽  
Cry Proteins ◽  
Cry Toxins ◽  
Content Type ◽  
Hsp90 Chaperone ◽  
Protease Degradation

ABSTRACT Bacillus thuringiensis Cry proteins are pore-forming insecticidal toxins with specificity against different crop pests and insect vectors of human diseases. Previous work suggested that the insect host Hsp90 chaperone could be involved in Cry toxin action. Here, we show that the interaction of Cry toxins with insect Hsp90 constitutes a positive loop to enhance the performance of these toxins. Plutella xylostella Hsp90 (PxHsp90) greatly enhanced Cry1Ab or Cry1Ac toxicity when fed together to P. xylostella larvae and also in the less susceptible Spodoptera frugiperda larvae. PxHsp90 bound Cry1Ab and Cry1Ac protoxins in an ATP- and chaperone activity-dependent interaction. The chaperone Hsp90 participates in the correct folding of proteins and may suppress mutations of some client proteins, and we show here that PxHsp90 recovered the toxicity of the Cry1AbG439D protoxin affected in receptor binding, in contrast to the Cry1AbR99E or Cry1AbE129K mutant, affected in oligomerization or membrane insertion, respectively, which showed a slight toxicity improvement. Specifically, PxHsp90 enhanced the binding of Cry1AbG439D protoxin to the cadherin receptor. Furthermore, PxHsp90 protected Cry1A protoxins from degradation by insect midgut proteases. Our data show that PxHsp90 assists Cry1A proteins by enhancing their binding to the receptor and by protecting Cry protoxin from gut protease degradation. Finally, we show that the insect cochaperone protein PxHsp70 also increases the toxicity of Cry1Ac in P. xylostella larvae, in contrast to a bacterial GroEL chaperone, which had a marginal effect, indicating that the use of insect chaperones along with Cry toxins could have important biotechnological applications for the improvement of Cry insecticidal activity, resulting in effective control of insect pests. IMPORTANCE Bacillus thuringiensis took advantage of important insect cellular proteins, such as chaperones, involved in maintaining protein homeostasis, to enhance its insecticidal activity. This constitutes a positive loop where the concentrations of Hsp90 and Hsp70 in the gut lumen are likely to increase as midgut cells burst due to Cry1A pore formation action. Hsp90 protects Cry1A protoxin from degradation and enhances receptor binding, resulting in increased toxicity. The effect of insect chaperones on Cry toxicity could have important biotechnological applications to enhance the toxicity of Cry proteins to insect pests, especially those that show low susceptibility to these toxins.

scholarly journals Novel Bacillus thuringiensis Binary Insecticidal Crystal Proteins Active on Western Corn Rootworm, Diabrotica virgifera virgifera LeConte

2002 ◽  
Vol 68 (3) ◽  
pp. 1137-1145 ◽  
Author(s):  
R. Tracy Ellis ◽  
Brian A. Stockhoff ◽  
Lisa Stamp ◽  
H. Ernest Schnepf ◽  
George E. Schwab ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Diabrotica Virgifera Virgifera ◽  
Bacillus Sphaericus ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Sequence Comparisons ◽  
Insecticidal Proteins ◽  
Crystal Proteins ◽  
Insecticidal Crystal Proteins

ABSTRACT A new family of insecticidal crystal proteins was discovered by screening sporulated Bacillus thuringiensis cultures for oral activity against western corn rootworm (WCR) larvae. B. thuringiensis isolates PS80JJ1, PS149B1, and PS167H2 have WCR insecticidal activity attributable to parasporal inclusion bodies containing proteins with molecular masses of ca. 14 and 44 kDa. The genes encoding these polypeptides reside in apparent operons, and the 14-kDa protein open reading frame (ORF) precedes the 44-kDa protein ORF. Mutagenesis of either gene in the apparent operons dramatically reduced insecticidal activity of the corresponding recombinant B. thuringiensis strain. Bioassays performed with separately expressed, biochemically purified 14- and 44-kDa polypeptides also demonstrated that both proteins are required for WCR mortality. Sequence comparisons with other known B. thuringiensis insecticidal proteins failed to reveal homology with previously described Cry, Cyt, or Vip proteins. However, there is evidence that the 44-kDa polypeptide and the 41.9- and 51.4-kDa binary dipteran insecticidal proteins from Bacillus sphaericus are evolutionarily related. The 14- and 44-kDa polypeptides from isolates PS80JJ1, PS149B1, and PS167H2 have been designated Cry34Aa1, Cry34Ab1, and Cry34Ac1, respectively, and the 44-kDa polypeptides from these isolates have been designated Cry35Aa1, Cry35Ab1, and Cry35Ac1, respectively.

scholarly journals The Cytocidal Spectrum of Bacillus thuringiensis Toxins: From Insects to Human Cancer Cells

Toxins ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 301 ◽  
Author(s):  
Gretel Mendoza-Almanza ◽  
Edgar L. Esparza-Ibarra ◽  
Jorge L. Ayala-Luján ◽  
Marisa Mercado-Reyes ◽  
Susana Godina-González ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Cell Membrane ◽  
Cancer Cells ◽  
Insecticidal Activity ◽  
Human Cancer ◽  
Membrane Receptors ◽  
Specific Cell ◽  
Cry Proteins ◽  
Cry Toxins ◽  
Human Cancer Cells

Bacillus thuringiensis (Bt) is a ubiquitous bacterium in soils, insect cadavers, phylloplane, water, and stored grain, that produces several proteins, each one toxic to different biological targets such as insects, nematodes, mites, protozoa, and mammalian cells. Most Bt toxins identify their particular target through the recognition of specific cell membrane receptors. Cry proteins are the best-known toxins from Bt and a great amount of research has been published. Cry are cytotoxic to insect larvae that affect important crops recognizing specific cell membrane receptors such as cadherin, aminopeptidase-N, and alkaline phosphatase. Furthermore, some Cry toxins such as Cry4A, Cry4B, and Cry11A act synergistically with Cyt toxins against dipteran larvae vectors of human disease. Research developed with Cry proteins revealed that these toxins also could kill human cancer cells through the interaction with specific receptors. Parasporins are a small group of patented toxins that may or may not have insecticidal activity. These proteins could kill a wide variety of mammalian cancer cells by recognizing specific membrane receptors, just like Cry toxins do. Surface layer proteins (SLP), unlike the other proteins produced by Bt, are also produced by most bacteria and archaebacteria. It was recently demonstrated that SLP produced by Bt could interact with membrane receptors of insect and human cancer cells to kill them. Cyt toxins have a structure that is mostly unrelated to Cry toxins; thereby, other mechanisms of action have been reported to them. These toxins affect mainly mosquitoes that are vectors of human diseases like Anopheles spp (malaria), Aedes spp (dengue, zika, and chikungunya), and Culex spp (Nile fever and Rift Valley fever), respectively. In addition to the Cry, Cyt, and parasporins toxins produced during spore formation as inclusion bodies, Bt strains also produce Vip (Vegetative insecticidal toxins) and Sip (Secreted insecticidal proteins) toxins with insecticidal activity during their vegetative growth phase.

scholarly journals Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 522
Author(s):  
Tahira Syed ◽  
Muhammad Askari ◽  
Zhigang Meng ◽  
Yanyan Li ◽  
Muhammad Ali Abid ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Mechanism Of Action ◽  
Insecticidal Activity ◽  
Binding Sites ◽  
Growth Phases ◽  
Cry Proteins ◽  
Insecticidal Proteins ◽  
Gram Negative ◽  
Vip Proteins ◽  
Evolution Of Resistance

Bacillus thuringiensis (Bt) is a Gram negative soil bacterium. This bacterium secretes various proteins during different growth phases with an insecticidal potential against many economically important crop pests. One of the important families of Bt proteins is vegetative insecticidal proteins (Vip), which are secreted into the growth medium during vegetative growth. There are three subfamilies of Vip proteins. Vip1 and Vip2 heterodimer toxins have an insecticidal activity against many Coleopteran and Hemipteran pests. Vip3, the most extensively studied family of Vip toxins, is effective against Lepidopteron. Vip proteins do not share homology in sequence and binding sites with Cry proteins, but share similarities at some points in their mechanism of action. Vip3 proteins are expressed as pyramids alongside Cry proteins in crops like maize and cotton, so as to control resistant pests and delay the evolution of resistance. Biotechnological- and in silico-based analyses are promising for the generation of mutant Vip proteins with an enhanced insecticidal activity and broader spectrum of target insects.

Persistence of Bacillus thuringiensis parasporal crystal insecticidal activity in soil

1984 ◽  
Vol 44 (2) ◽  
pp. 128-133 ◽  
Author(s):  
Andrew W. West ◽  
H.D. Burges ◽  
R.J. White ◽  
C.H. Wyborn
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Parasporal Crystal
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