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Enhancins are metalloproteinases that facilitate baculovirus infection in the insect midgut. They are more prevalent in granuloviruses (GVs), constituting up to 5% of the proteins of viral occlusion bodies (OBs). In nucleopolyhedroviruses (NPVs), in contrast, they are present in the envelope of the occlusion-derived virions (ODV). In the present study, we constructed a recombinant Autographa californica NPV (AcMNPV) that expressed the Trichoplusia ni GV (TnGV) enhancin 3 (En3), with the aim of increasing the presence of enhancin in the OBs or ODVs. En3 was successfully produced but did not localize to the OBs or the ODVs and accumulated in the soluble fraction of infected cells. As a result, increased OB pathogenicity was observed when OBs were administered in mixtures with the soluble fraction of infected cells. The mixture of OBs and the soluble fraction of Sf9 cells infected with BacPhEn3 recombinant virus was ~3- and ~4.7-fold more pathogenic than BacPh control OBs in the second and fourth instars of Spodoptera exigua, respectively. In contrast, when purified, recombinant BacPhEn3 OBs were as pathogenic as control BacPh OBs. The expression of En3 in the soluble fraction of insect cells may find applications in the development of virus-based insecticides with increased efficacy.
Adriana Ricarte-Bermejo; Oihane Simón; Ana Fernández; Trevor Williams; Primitivo Caballero. Bacmid Expression of Granulovirus Enhancin En3 Accumulates in Cell Soluble Fraction to Potentiate Nucleopolyhedrovirus Infection. Viruses 2021, 13, 1233 .
AMA StyleAdriana Ricarte-Bermejo, Oihane Simón, Ana Fernández, Trevor Williams, Primitivo Caballero. Bacmid Expression of Granulovirus Enhancin En3 Accumulates in Cell Soluble Fraction to Potentiate Nucleopolyhedrovirus Infection. Viruses. 2021; 13 (7):1233.
Chicago/Turabian StyleAdriana Ricarte-Bermejo; Oihane Simón; Ana Fernández; Trevor Williams; Primitivo Caballero. 2021. "Bacmid Expression of Granulovirus Enhancin En3 Accumulates in Cell Soluble Fraction to Potentiate Nucleopolyhedrovirus Infection." Viruses 13, no. 7: 1233.
Alphabaculoviruses are used as biological insecticides and expression vectors in biotechnology and medical applications. We demonstrate that in caterpillars infected with particular mixtures of viruses, the genomes of different baculovirus species can be enveloped together within individual virions and occluded within proteinaceous occlusion bodies.
Inés Beperet; Oihane Simón; Miguel López-Ferber; Jan van Lent; Trevor Williams; Primitivo Caballero. Mixtures of Insect-Pathogenic Viruses in a Single Virion: towards the Development of Custom-Designed Insecticides. Applied and Environmental Microbiology 2021, 87, 1 .
AMA StyleInés Beperet, Oihane Simón, Miguel López-Ferber, Jan van Lent, Trevor Williams, Primitivo Caballero. Mixtures of Insect-Pathogenic Viruses in a Single Virion: towards the Development of Custom-Designed Insecticides. Applied and Environmental Microbiology. 2021; 87 (3):1.
Chicago/Turabian StyleInés Beperet; Oihane Simón; Miguel López-Ferber; Jan van Lent; Trevor Williams; Primitivo Caballero. 2021. "Mixtures of Insect-Pathogenic Viruses in a Single Virion: towards the Development of Custom-Designed Insecticides." Applied and Environmental Microbiology 87, no. 3: 1.
The control of dipteran pests is highly relevant to humans due to their involvement in the transmission of serious diseases including malaria, dengue fever, Chikungunya, yellow fever, zika, and filariasis; as well as their agronomic impact on numerous crops. Many bacteria are able to produce proteins that are active against insect species. These bacteria include Bacillus thuringiensis, the most widely-studied pesticidal bacterium, which synthesizes proteins that accumulate in crystals with insecticidal properties and which has been widely used in the biological control of insects from different orders, including Lepidoptera, Coleoptera, and Diptera. In this review, we summarize all the bacterial proteins, from B. thuringiensis and other entomopathogenic bacteria, which have described insecticidal activity against dipteran pests, including species of medical and agronomic importance.
Daniel Valtierra-De-Luis; Maite Villanueva; Colin Berry; Primitivo Caballero. Potential for Bacillus thuringiensis and Other Bacterial Toxins as Biological Control Agents to Combat Dipteran Pests of Medical and Agronomic Importance. Toxins 2020, 12, 773 .
AMA StyleDaniel Valtierra-De-Luis, Maite Villanueva, Colin Berry, Primitivo Caballero. Potential for Bacillus thuringiensis and Other Bacterial Toxins as Biological Control Agents to Combat Dipteran Pests of Medical and Agronomic Importance. Toxins. 2020; 12 (12):773.
Chicago/Turabian StyleDaniel Valtierra-De-Luis; Maite Villanueva; Colin Berry; Primitivo Caballero. 2020. "Potential for Bacillus thuringiensis and Other Bacterial Toxins as Biological Control Agents to Combat Dipteran Pests of Medical and Agronomic Importance." Toxins 12, no. 12: 773.
Baculoviruses (BV) are highly effective against lepidopteran pests of economic importance such as Spodoptera exigua. The combined use of entomopathogens and macrobiological control agents requires the study of their relationships. Laboratory bioassays were developed to evaluate the interactions between the multiple nucleopolyhedroviruses of S. exigua (SeMNPV) and Autographa californica (AcMNPV), and the predator Chrysoperla carnea. The microscopic examination of predator’s excreta (larval drops and meconia) after the ingestion of BV-infected S. exigua revealed the presence of viral occlusion bodies (OBs). The reinfection of S. exigua larvae with BVs-contaminated excreta by using OBs water suspensions or by direct application both yielded high mortality values but different speed-of-kill results. Meconia killed before in suspensions due to their higher viral load and larval excretion drops did so in direct application due to their liquid nature and their easiness of consumption. The prey-mediated ingestion of SeMNPV and AcMNPV triggered slight effects in C. carnea, which were probably derived from the food nutritional quality. Chrysoperla carnea larvae did not discriminate between healthy and BV-infected S. exigua, while a preference was shown for S. exigua (healthy or infected) vs. Macrosiphum euphorbiae. Our findings present C. carnea, and particularly its larvae, as a promissory candidate for BV dispersion in the field.
Oscar Gutiérrez-Cárdenas; Ángeles Adán; Inés Beperet; Pilar Medina; Primitivo Caballero; Agustín Garzón. The Role of Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) as a Potential Dispersive Agent of Noctuid Baculoviruses. Insects 2020, 11, 760 .
AMA StyleOscar Gutiérrez-Cárdenas, Ángeles Adán, Inés Beperet, Pilar Medina, Primitivo Caballero, Agustín Garzón. The Role of Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) as a Potential Dispersive Agent of Noctuid Baculoviruses. Insects. 2020; 11 (11):760.
Chicago/Turabian StyleOscar Gutiérrez-Cárdenas; Ángeles Adán; Inés Beperet; Pilar Medina; Primitivo Caballero; Agustín Garzón. 2020. "The Role of Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) as a Potential Dispersive Agent of Noctuid Baculoviruses." Insects 11, no. 11: 760.
The mode of action underlying the insecticidal activity of the Bacillus thuringiensis (Bt) binary pesticidal protein Vpa1/Vpa2 is uncertain. In this study, three recombinant baculoviruses were constructed using Bac-to-Bac technology to express Vpa2Ac1 and two novel Vpa2-like genes, Vpa2-like1 and Vpa2-like2, under the baculovirus p10 promoter in transfected Sf9 cells. Pairwise amino acid analyses revealed a higher percentage of identity and a lower number of gaps between Vpa2Ac1 and Vpa2-like2 than to Vpa2-like1. Moreover, Vpa2-like1 lacked the conserved Ser-Thr-Ser motif, involved in NAD binding, and the (F/Y)xx(Q/E)xE consensus sequence, characteristic of the ARTT toxin family involved in actin polymerization. Vpa2Ac1, Vpa2-like1 and Vpa2-like2 transcripts and proteins were detected in Sf9 culture cells, but the signals of Vpa2Ac1 and Vpa2-like2 were weak and decreased over time. Sf9 cells infected by a recombinant bacmid expressing Vpa2-like1 showed typical circular morphology and produced viral occlusion bodies (OBs) at the same level as the control virus. However, expression of Vpa2Ac1 and Vpa2-like2 induced cell polarization, similar to that produced by the microfilament-destabilizing agent cytochalasin D and OBs were not produced. The presence of filament disrupting agents, such as nicotinamide and nocodazole, during transfection prevented cell polarization and OB production was observed. We conclude that Vpa2Ac1 and Vpa2-like2 proteins likely possess ADP-ribosyltransferase activity that modulated actin polarization, whereas Vpa2-like1 is not a typical Vpa2 protein. Vpa2-like2 has now been designated Vpa2Ca1 (accession number AAO86513) by the Bacillus thuringiensis delta-endotoxin nomenclature committee.
Oihane Simón; Leopoldo Palma; Ana Beatriz Fernández; Trevor Williams; Primitivo Caballero. Baculovirus Expression and Functional Analysis of Vpa2 Proteins from Bacillus thuringiensis. Toxins 2020, 12, 543 .
AMA StyleOihane Simón, Leopoldo Palma, Ana Beatriz Fernández, Trevor Williams, Primitivo Caballero. Baculovirus Expression and Functional Analysis of Vpa2 Proteins from Bacillus thuringiensis. Toxins. 2020; 12 (9):543.
Chicago/Turabian StyleOihane Simón; Leopoldo Palma; Ana Beatriz Fernández; Trevor Williams; Primitivo Caballero. 2020. "Baculovirus Expression and Functional Analysis of Vpa2 Proteins from Bacillus thuringiensis." Toxins 12, no. 9: 543.
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.
Mikel Domínguez-Arrizabalaga; Maite Villanueva; Baltasar Escriche; Carmen Ancín-Azpilicueta; Primitivo Caballero. Insecticidal Activity of Bacillus thuringiensis Proteins Against Coleopteran Pests. Toxins 2020, 12, 430 .
AMA StyleMikel Domínguez-Arrizabalaga, Maite Villanueva, Baltasar Escriche, Carmen Ancín-Azpilicueta, Primitivo Caballero. Insecticidal Activity of Bacillus thuringiensis Proteins Against Coleopteran Pests. Toxins. 2020; 12 (7):430.
Chicago/Turabian StyleMikel Domínguez-Arrizabalaga; Maite Villanueva; Baltasar Escriche; Carmen Ancín-Azpilicueta; Primitivo Caballero. 2020. "Insecticidal Activity of Bacillus thuringiensis Proteins Against Coleopteran Pests." Toxins 12, no. 7: 430.
Bacillus thuringiensis (Bt)-based biological insecticides are used extensively to control insect pests and vectors of human diseases. Bt-based products provide greater specificity and biosafety than broad-spectrum synthetic insecticides. The biological activity of this bacterium resides in spores and crystals comprising complex mixtures of toxic proteins. We developed and validated a fast, accurate, and reproducible method for quantitative determination of the crystal components of Bt-based products. This method will find clear applications in the improvement of various aspects of the industrial production process of Bt. An important aspect of the production of Bt-based insecticides is its quality control. By specifically quantifying the relative proportion of each of the toxins that make up the crystal, our method represents the most consistent and repeatable evaluation procedure in the quality control of different batches produced in successive fermentations. This method can also contribute to the design of specific culture media and fermentation conditions that optimize Bt crystal composition across a range of Bt strains that target different pestiferous insects. Quantitative information on crystal composition should also prove valuable to phytosanitary product registration authorities that oversee the safety and efficacy of crop protection products.
Javier Caballero; Nerea Jiménez-Moreno; Irene Orera; Trevor Williams; Ana B. Fernández; Maite Villanueva; Juan Ferré; Primitivo Caballero; Carmen Ancín-Azpilicueta. Unraveling the Composition of Insecticidal Crystal Proteins in Bacillus thuringiensis: a Proteomics Approach. Applied and Environmental Microbiology 2020, 86, 1 .
AMA StyleJavier Caballero, Nerea Jiménez-Moreno, Irene Orera, Trevor Williams, Ana B. Fernández, Maite Villanueva, Juan Ferré, Primitivo Caballero, Carmen Ancín-Azpilicueta. Unraveling the Composition of Insecticidal Crystal Proteins in Bacillus thuringiensis: a Proteomics Approach. Applied and Environmental Microbiology. 2020; 86 (12):1.
Chicago/Turabian StyleJavier Caballero; Nerea Jiménez-Moreno; Irene Orera; Trevor Williams; Ana B. Fernández; Maite Villanueva; Juan Ferré; Primitivo Caballero; Carmen Ancín-Azpilicueta. 2020. "Unraveling the Composition of Insecticidal Crystal Proteins in Bacillus thuringiensis: a Proteomics Approach." Applied and Environmental Microbiology 86, no. 12: 1.
Bacillus thuringiensis ser. israelensis (Bti) has been widely used as microbial larvicide for the control of many species of mosquitoes and blackflies. The larvicidal activity of Bti resides in Cry and Cyt δ-endotoxins present in the parasporal crystal of this pathogen. The insecticidal activity of the crystal is higher than the activities of the individual toxins, which is likely due to synergistic interactions among the crystal component proteins, particularly those involving Cyt1Aa. In the present study, Cry10Aa and Cyt2Ba were cloned from the commercial larvicide VectoBac-12AS® and expressed in the acrystalliferous Bt strain BMB171 under the cyt1Aa strong promoter of the pSTAB vector. The LC50 values for Aedes aegypti second instar larvae estimated at 24 hpi for these two recombinant proteins (Cry10Aa and Cyt2Ba) were 299.62 and 279.37 ng/mL, respectively. Remarkable synergistic mosquitocidal activity was observed between Cry10Aa and Cyt2Ba (synergistic potentiation of 68.6-fold) when spore + crystal preparations, comprising a mixture of both recombinant strains in equal relative concentrations, were ingested by A. aegypti larvae. This synergistic activity is among the most powerful described so far with Bt toxins and is comparable to that reported for Cyt1A when interacting with Cry4Aa, Cry4Ba or Cry11Aa. Synergistic mosquitocidal activity was also observed between the recombinant proteins Cyt2Ba and Cry4Aa, but in this case, the synergistic potentiation was 4.6-fold. In conclusion, although Cry10Aa and Cyt2Ba are rarely detectable or appear as minor components in the crystals of Bti strains, they represent toxicity factors with a high potential for the control of mosquito populations.
Daniel Valtierra-De-Luis; Maite Villanueva; Liliana Lai; Trevor Williams; Primitivo Caballero. Potential of Cry10Aa and Cyt2Ba, Two Minority δ-endotoxins Produced by Bacillus thuringiensis ser. israelensis, for the Control of Aedes aegypti Larvae. Toxins 2020, 12, 355 .
AMA StyleDaniel Valtierra-De-Luis, Maite Villanueva, Liliana Lai, Trevor Williams, Primitivo Caballero. Potential of Cry10Aa and Cyt2Ba, Two Minority δ-endotoxins Produced by Bacillus thuringiensis ser. israelensis, for the Control of Aedes aegypti Larvae. Toxins. 2020; 12 (6):355.
Chicago/Turabian StyleDaniel Valtierra-De-Luis; Maite Villanueva; Liliana Lai; Trevor Williams; Primitivo Caballero. 2020. "Potential of Cry10Aa and Cyt2Ba, Two Minority δ-endotoxins Produced by Bacillus thuringiensis ser. israelensis, for the Control of Aedes aegypti Larvae." Toxins 12, no. 6: 355.
The joint use of baculoviruses and synthetic insecticides for integrated pest management requires the study of the additive, synergistic or antagonistic effects among them on pest mortality. Droplet bioassays were conducted with Autographa californica multiple nucleopolyhedrovirus (AcMNPV), Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) and seven insecticides (azadirachtin, Bacillus thuringiensis, cyantraniliprole, emamectin, metaflumizone, methoxyfenozide and spinetoram) on Spodoptera exigua and Spodoptera littoralis. The lethal concentrations LC50 and LC95 were calculated through probit regressions. Then, the sequential feeding of insecticides and nucleopolyhedroviruses was studied. Larvae were provided with the LC50 of one insecticide, followed by the LC50 of one nucleopolyhedrovirus 24 h later. The inverse order was also conducted. The insecticide LC50 and LC95 were higher for S. littoralis than for S. exigua. AcMNPV showed greater toxicity on S. exigua than SpliNPV on S. littoralis. Emamectin showed synergy with AcMNPV when the chemical was applied first, and metaflumizone and AcMNPV were synergistic regardless of the order of application, both from the first day of evaluation. SpliNPV was synergistic with azadirachtin and emamectin when it was applied first, but synergy was reached after 12–13 days. Excellent control is possible with the LC50 of azadirachtin, emamectin and metaflumizone in combination with nucleopolyhedroviruses, and merits further study as a means of controlling lepidopteran pests.
Beatriz Dáder; Eduardo Aguirre; Primitivo Caballero; Pilar Medina. Synergy of Lepidopteran Nucleopolyhedroviruses AcMNPV and SpliNPV with Insecticides. Insects 2020, 11, 316 .
AMA StyleBeatriz Dáder, Eduardo Aguirre, Primitivo Caballero, Pilar Medina. Synergy of Lepidopteran Nucleopolyhedroviruses AcMNPV and SpliNPV with Insecticides. Insects. 2020; 11 (5):316.
Chicago/Turabian StyleBeatriz Dáder; Eduardo Aguirre; Primitivo Caballero; Pilar Medina. 2020. "Synergy of Lepidopteran Nucleopolyhedroviruses AcMNPV and SpliNPV with Insecticides." Insects 11, no. 5: 316.
Naturally occurring covert infections in lepidopteran populations can involve multiple viruses with potentially different transmission strategies. In this study, we characterized covert infection by two RNA viruses, Spodoptera exigua iflavirus 1 (SeIV-1) and Spodoptera exigua iflavirus 2 (SeIV-2) (family Iflaviridae) that naturally infect populations of Spodoptera exigua, and examined their influence on susceptibility to patent disease by the nucleopolyhedrovirus Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) (family Baculoviridae). The abundance of SeIV-1 genomes increased up to ten-thousand-fold across insect developmental stages after surface contamination of host eggs with a mixture of SeIV-1 and SeIV-2 particles, whereas the abundance of SeIV-2 remained constant across all developmental stages. Low levels of SeIV-2 infection were detected in all groups of insects, including those that hatched from surface-decontaminated egg masses. SeIV-1 infection resulted in reduced larval weight gain, and an unbalanced sex ratio, whereas larval developmental time, pupal weight, and adult emergence and fecundity were not significantly affected in infected adults. The inoculation of S. exigua egg masses with iflavirus, followed by a subsequent infection with SeMNPV, resulted in an additive effect on larval mortality. The 50% lethal concentration (LC50) of SeMNPV was reduced nearly 4-fold and the mean time to death was faster by 12 h in iflavirus-treated insects. These results suggest that inapparent iflavirus infections may be able to modulate the host response to a new pathogen, a finding that has particular relevance to the use of SeMNPV as the basis for biological pest control products.
Arkaitz Carballo; Trevor Williams; Rosa Murillo; Primitivo Caballero. Iflavirus Covert Infection Increases Susceptibility to Nucleopolyhedrovirus Disease in Spodoptera exigua. Viruses 2020, 12, 509 .
AMA StyleArkaitz Carballo, Trevor Williams, Rosa Murillo, Primitivo Caballero. Iflavirus Covert Infection Increases Susceptibility to Nucleopolyhedrovirus Disease in Spodoptera exigua. Viruses. 2020; 12 (5):509.
Chicago/Turabian StyleArkaitz Carballo; Trevor Williams; Rosa Murillo; Primitivo Caballero. 2020. "Iflavirus Covert Infection Increases Susceptibility to Nucleopolyhedrovirus Disease in Spodoptera exigua." Viruses 12, no. 5: 509.
Bacillus thuringiensis (Bt) produces insecticidal proteins that are either secreted during the vegetative growth phase or accumulated in the crystal inclusions (Cry proteins) in the stationary phase. Cry1I proteins share the three domain (3D) structure typical of crystal proteins but are secreted to the media early in the stationary growth phase. In the generally accepted mode of action of 3D Cry proteins (sequential binding model), the formation of an oligomer (tetramer) has been described as a major step, necessary for pore formation and subsequent toxicity. To know if this could be extended to Cry1I proteins, the formation of Cry1Ia oligomers was studied by Western blot, after the incubation of trypsin activated Cry1Ia with insect brush border membrane vesicles (BBMV) or insect cultured cells, using Cry1Ab as control. Our results showed that Cry1Ia oligomers were observed only after incubation with susceptible coleopteran BBMV, but not following incubation with susceptible lepidopteran BBMV or non-susceptible Sf21 insect cells, while Cry1Ab oligomers were persistently detected after incubation with all insect tissues tested, regardless of its host susceptibility. The data suggested oligomerization may not necessarily be a requirement for the toxicity of Cry1I proteins.
Ayda Khorramnejad; Mikel Domínguez-Arrizabalaga; Primitivo Caballero; Baltasar Escriche; Yolanda Bel. Study of the Bacillus thuringiensis Cry1Ia Protein Oligomerization Promoted by Midgut Brush Border Membrane Vesicles of Lepidopteran and Coleopteran Insects, or Cultured Insect Cells. Toxins 2020, 12, 133 .
AMA StyleAyda Khorramnejad, Mikel Domínguez-Arrizabalaga, Primitivo Caballero, Baltasar Escriche, Yolanda Bel. Study of the Bacillus thuringiensis Cry1Ia Protein Oligomerization Promoted by Midgut Brush Border Membrane Vesicles of Lepidopteran and Coleopteran Insects, or Cultured Insect Cells. Toxins. 2020; 12 (2):133.
Chicago/Turabian StyleAyda Khorramnejad; Mikel Domínguez-Arrizabalaga; Primitivo Caballero; Baltasar Escriche; Yolanda Bel. 2020. "Study of the Bacillus thuringiensis Cry1Ia Protein Oligomerization Promoted by Midgut Brush Border Membrane Vesicles of Lepidopteran and Coleopteran Insects, or Cultured Insect Cells." Toxins 12, no. 2: 133.
The bacterium Bacillus thuringiensis produces insecticidal Vip3 proteins during the vegetative growth phase with activity against several lepidopteran pests. To date, three different Vip3 protein families have been identified based on sequence identity: Vip3A, Vip3B, and Vip3C. In this study, we report the construction of chimeras by exchanging domains between Vip3Aa and Vip3Ca, two proteins with marked specificity differences against lepidopteran pests. We found that some domain combinations made proteins insoluble or prone to degradation by trypsin as most abundant insect gut protease. The soluble and trypsin-stable chimeras, along with the parental proteins Vip3Aa and Vip3Ca, were tested against lepidopteran pests from different continents: Spodoptera exigua, Spodoptera littoralis, Spodoptera frugiperda, Helicoverpa armigera, Mamestra brassicae, Anticarsia gemmatalis, and Ostrinia furnacalis. The exchange of the Nt domain (188 N-terminal amino acids) had little effect on the stability and toxicity (equal or slightly lower) of the resulting chimeric protein against all insects except for S. frugiperda, for which the chimera with the Nt domain from Vip3Aa and the rest of the protein from Vip3Ca showed a significant increase in toxicity compared to the parental Vip3Ca. Chimeras with the C-terminal domain from Vip3Aa (from amino acid 510 of Vip3Aa to the Ct) with the central domain of Vip3Ca (amino acids 189–509 based on the Vip3Aa sequence) made proteins that could not be solubilized. Finally, the chimera including the Ct domain of Vip3Ca and the Nt and central domain from Vip3Aa was unstable. Importantly, an insect species tolerant to Vip3Aa but susceptible to Vip3Ca, such as Ostrinia furnacalis, was also susceptible to chimeras maintaining the Ct domain from Vip3Ca, in agreement with the hypothesis that the Ct region of the protein is the one conferring specificity to Vip3 proteins.
Joaquín Gomis-Cebolla; Rafael Ferreira dos Santos; Yueqin Wang; Javier Caballero; Primitivo Caballero; Kanglai He; Juan Jurat-Fuentes; Juan Ferré. Domain Shuffling between Vip3Aa and Vip3Ca: Chimera Stability and Insecticidal Activity against European, American, African, and Asian Pests. Toxins 2020, 12, 99 .
AMA StyleJoaquín Gomis-Cebolla, Rafael Ferreira dos Santos, Yueqin Wang, Javier Caballero, Primitivo Caballero, Kanglai He, Juan Jurat-Fuentes, Juan Ferré. Domain Shuffling between Vip3Aa and Vip3Ca: Chimera Stability and Insecticidal Activity against European, American, African, and Asian Pests. Toxins. 2020; 12 (2):99.
Chicago/Turabian StyleJoaquín Gomis-Cebolla; Rafael Ferreira dos Santos; Yueqin Wang; Javier Caballero; Primitivo Caballero; Kanglai He; Juan Jurat-Fuentes; Juan Ferré. 2020. "Domain Shuffling between Vip3Aa and Vip3Ca: Chimera Stability and Insecticidal Activity against European, American, African, and Asian Pests." Toxins 12, no. 2: 99.
The genome of the Bacillus thuringiensis BM311.1 strain was sequenced and assembled in 359 contigs containing a total of 6,390,221 bp. The plasmidic ORF of a putative cry gene from this strain was identified as a potential novel Cry protein of 1138 amino acid residues with a 98% identity compared to Cry7Aa1 and a predicted molecular mass of 129.4 kDa. The primary structure of Cry7Aa2, which had eight conserved blocks and the classical structure of three domains, differed in 28 amino acid residues from that of Cry7Aa1. The cry7Aa2 gene was amplified by PCR and then expressed in the acrystalliferous strain BMB171. SDS-PAGE analysis confirmed the predicted molecular mass for the Cry7Aa2 protein and revealed that after in vitro trypsin incubation, the protein was degraded to a toxin of 62 kDa. However, when treated with digestive fluids from Leptinotarsa decemlineata larvae, one major proteinase-resistant fragment of slightly smaller size was produced. The spore and crystal mixture produced by the wild-type BM311.1 strain against L. decemlineata neonate larvae resulted in a LC50 value of 18.8 μg/mL, which was statistically similar to the estimated LC50 of 20.8 μg/mL for the recombinant BMB17-Cry7Aa2 strain. In addition, when this novel toxin was activated in vitro with commercial trypsin, the LC50 value was reduced 3.8-fold to LC50 = 4.9 μg/mL. The potential advantages of Cry7Aa2 protoxin compared to Cry7Aa1 protoxin when used in the control of insect pests are discussed.
Mikel Domínguez-Arrizabalaga; Maite Villanueva; Ana Beatriz Fernandez; Primitivo Caballero. A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene that Is Toxic to Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). Insects 2019, 10, 259 .
AMA StyleMikel Domínguez-Arrizabalaga, Maite Villanueva, Ana Beatriz Fernandez, Primitivo Caballero. A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene that Is Toxic to Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). Insects. 2019; 10 (9):259.
Chicago/Turabian StyleMikel Domínguez-Arrizabalaga; Maite Villanueva; Ana Beatriz Fernandez; Primitivo Caballero. 2019. "A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene that Is Toxic to Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae)." Insects 10, no. 9: 259.
Phylogenetic analyses suggest that Mamestra brassicae multiple nucleopolyhedrovirus (MbMNPV) and Helicoverpa armigera multiple nucleopolyhedrovirus (HearMNPV) may be strains of the same virus species. Most of the studies comparing their biological activities have been performed in their homologous hosts. A comparison of host range and stability in alternative hosts was performed. The host range of these viruses was compared using high concentrations of inoculum to inoculate second instars of six species of Lepidoptera. One semi-permissive host (Spodoptera littoralis) and one permissive host (S. exigua) were then selected and used to perform six serial passages involving a concentration corresponding to the ~25% lethal concentration for both viruses. Restriction endonuclease analysis showed fragment length polymorphisms in every host-virus system studied. In S. littoralis, serial passage of MbMNPV resulted in decreased pathogenicity and an increase in speed-of-kill, whereas no significant changes were detected for HearMNPV with respect to the initial inoculum. In contrast, both viruses showed a similar trend in S. exigua. These results highlight the low genetic diversity and a high phenotypic stability of HearMNPV with respect to the original inoculum after six successive passages in both insect hosts. This study concludes that host-baculovirus interactions during serial passage are complex and the process of adaptation to a novel semi-permissive host is far from predictable.
Isabel M. Belda; Inés Beperet; Trevor Williams; Primitivo Caballero. Genetic Variation and Biological Activity of Two Closely Related Alphabaculoviruses during Serial Passage in Permissive and Semi-Permissive Heterologous Hosts. Viruses 2019, 11, 660 .
AMA StyleIsabel M. Belda, Inés Beperet, Trevor Williams, Primitivo Caballero. Genetic Variation and Biological Activity of Two Closely Related Alphabaculoviruses during Serial Passage in Permissive and Semi-Permissive Heterologous Hosts. Viruses. 2019; 11 (7):660.
Chicago/Turabian StyleIsabel M. Belda; Inés Beperet; Trevor Williams; Primitivo Caballero. 2019. "Genetic Variation and Biological Activity of Two Closely Related Alphabaculoviruses during Serial Passage in Permissive and Semi-Permissive Heterologous Hosts." Viruses 11, no. 7: 660.
Genetic variation in baculoviruses is recognized as a key factor, not only due to the influence of such variation on pathogen transmission and virulence traits, but also because genetic variants can form the basis for novel biological insecticides. In this study, we examined the genetic variability of Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) present in field isolates obtained from virus-killed larvae. Different ChinNPV strains were identified by restriction endonuclease analysis, from which genetic variants were isolated by plaque assay. Biological characterization studies were based on pathogenicity, median time to death (MTD), and viral occlusion body (OB) production (OBs/larva). Nine different isolates were obtained from eleven virus-killed larvae collected from fields of soybean in Mexico. An equimolar mixture of these isolates, named ChinNPV-Mex1, showed good insecticidal properties and yielded 23 genetic variants by plaque assay, one of which (ChinNPV-R) caused the highest mortality in second instars of C. includens. Five of these variants were selected: ChinNPV-F, ChinNPV-J, ChinNPV-K, ChinNPV-R, and ChinNPV-V. No differences in median time to death were found between them, while ChinNPV-F, ChinNPV-K, ChinNPV-R and ChinNPV-V were more productive than ChinNPV-J and the original mixture of field isolates ChinNPV-Mex1. These results demonstrate the high variability present in natural populations of this virus and support the use of these new genetic variants as promising active substances for baculovirus-based bioinsecticides.
Eduardo Aguirre; Inés Beperet; Trevor Williams; Primitivo Caballero. Genetic Variability of Chrysodeixis Includens Nucleopolyhedrovirus (ChinNPV) and the Insecticidal Characteristics of Selected Genotypic Variants. Viruses 2019, 11, 581 .
AMA StyleEduardo Aguirre, Inés Beperet, Trevor Williams, Primitivo Caballero. Genetic Variability of Chrysodeixis Includens Nucleopolyhedrovirus (ChinNPV) and the Insecticidal Characteristics of Selected Genotypic Variants. Viruses. 2019; 11 (7):581.
Chicago/Turabian StyleEduardo Aguirre; Inés Beperet; Trevor Williams; Primitivo Caballero. 2019. "Genetic Variability of Chrysodeixis Includens Nucleopolyhedrovirus (ChinNPV) and the Insecticidal Characteristics of Selected Genotypic Variants." Viruses 11, no. 7: 581.
The genome of the Bacillus thuringiensis BM311.1 strain was sequenced and assembled in 359 contigs containing a total of 6,390,221 bp. The plasmidic ORF of a putative cry gene from this strain was identified as a potential novel Cry protein of 1138 amino acid residues with a 98% identity respect to Cry7Aa1 protein and a predicted molecular mass of 129.4 kDa. The primary structure of this Cry7Aa2 protein, which revealed the presence of eight conserved blocks and the classical structure of three domains, differed in 28 amino acid residues from that of Cry7Aa1. The cry7Aa2 gene was amplified by PCR and then expressed in the acrystalliferous strain BMB171. SDS-PAGE analysis confirmed the predicted molecular mass for the Cry7Aa2 protein and revealed that, after in vitro trypsin incubation, it was degraded to a toxin of 62 kDa. However, when treated with digestive fluids from Leptinotarsa decemlineata larvae two proteinase-resistant fragments of 60 and 65 kDa were produced. Spore and crystal mixture produced by the wild-type BM311.1 strain against L. decemlineata neonate larvae resulted in a LC50 (18.8 μg/ml), which was statistically equal to the estimated LC50 (20.8 μg/mL) for the recombinant BMB17-Cry7Aa2 strain. In addition, when this novel toxin was activated in vitro with commercial trypsin, the LC50 value was reduced 4 times approximately (LC50 = 4.9 μg/mL). The advantages of Cry7Aa2 protoxin compared to Cry7Aa1 protoxin when used in the control of insect pests are discussed.
Mikel Dominguez-; Maite Villanueva; Ana Beatriz Fernandez; Primitivo Caballero. A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene That Is Highly Toxic to Leptinotarsa decemlineata (Say) (Coleoptera; Chrysomelidae). 2019, 1 .
AMA StyleMikel Dominguez-, Maite Villanueva, Ana Beatriz Fernandez, Primitivo Caballero. A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene That Is Highly Toxic to Leptinotarsa decemlineata (Say) (Coleoptera; Chrysomelidae). . 2019; ():1.
Chicago/Turabian StyleMikel Dominguez-; Maite Villanueva; Ana Beatriz Fernandez; Primitivo Caballero. 2019. "A Strain of Bacillus thuringiensis Containing a Novel cry7Aa2 Gene That Is Highly Toxic to Leptinotarsa decemlineata (Say) (Coleoptera; Chrysomelidae)." , no. : 1.
Christian Del-Angel; Rodrigo Lasa; Luis A. Rodríguez-Del-Bosque; Gabriel Mercado; Inés Beperet; Primitivo Caballero; Trevor Williams. Anticarsia gemmatalis Nucleopolyhedrovirus from Soybean Crops in Tamaulipas, Mexico: Diversity and Insecticidal Characteristics of Individual Variants and their Co-Occluded Mixtures. Florida Entomologist 2018, 101, 404 -410.
AMA StyleChristian Del-Angel, Rodrigo Lasa, Luis A. Rodríguez-Del-Bosque, Gabriel Mercado, Inés Beperet, Primitivo Caballero, Trevor Williams. Anticarsia gemmatalis Nucleopolyhedrovirus from Soybean Crops in Tamaulipas, Mexico: Diversity and Insecticidal Characteristics of Individual Variants and their Co-Occluded Mixtures. Florida Entomologist. 2018; 101 (3):404-410.
Chicago/Turabian StyleChristian Del-Angel; Rodrigo Lasa; Luis A. Rodríguez-Del-Bosque; Gabriel Mercado; Inés Beperet; Primitivo Caballero; Trevor Williams. 2018. "Anticarsia gemmatalis Nucleopolyhedrovirus from Soybean Crops in Tamaulipas, Mexico: Diversity and Insecticidal Characteristics of Individual Variants and their Co-Occluded Mixtures." Florida Entomologist 101, no. 3: 404-410.
The Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) is the basis for viral insecticides in several countries in Latin America. The rate of acquisition of infection and the transmission of the pathogen from infected to healthy conspecifics both influence the efficacy of virus insecticides. By comparing the leaf area consumed by larvae with their stage-specific susceptibility to infection, we estimated that fourth instars were approximately twice as likely to acquire infection as second or third instars. Greenhouse trials indicated that 63% of third instars became infected within 1 h of exposure to soya plants treated with 1.5 x 107 occlusion bodies (OB)/m2 obtained from mixtures of local AgMNPV isolates, as did 90% of larvae sampled at 24 h. Acquisition of lethal infection was slower in field trials performed in the soya-growing Huastecas region of Mexico. Virus-induced mortality varied from 43 to 79% in natural infestations of larvae sampled at 72 h post-application depending on the dose of unformulated OBs applied with wetting agent, although the majority of larvae had already acquired a lethal infection at 24 h post-application. Spray application volume (200 or 400 l/ha) did not significantly affect the prevalence of infection at 1 h post-application. Infected fifth instars moved twice as far and died significantly higher on plants than control larvae. Overall, 22% of third instars that subsequently foraged on these plants acquired a lethal infection. We conclude that most insects acquire infection within 24 h of virus application and that OBs in feces and regurgitate of infected larvae contribute significantly to pathogen transmission.
Christian Del-Angel; Rodrigo Lasa; Gabriel Mercado; Luis A. Rodríguez-Del-Bosque; Primitivo Caballero; Trevor Williams. Acquisition of lethal infection, hypermobility and modified climbing behavior in nucleopolyhedrovirus infected larvae of Anticarsia gemmatalis. Biological Control 2018, 125, 90 -97.
AMA StyleChristian Del-Angel, Rodrigo Lasa, Gabriel Mercado, Luis A. Rodríguez-Del-Bosque, Primitivo Caballero, Trevor Williams. Acquisition of lethal infection, hypermobility and modified climbing behavior in nucleopolyhedrovirus infected larvae of Anticarsia gemmatalis. Biological Control. 2018; 125 ():90-97.
Chicago/Turabian StyleChristian Del-Angel; Rodrigo Lasa; Gabriel Mercado; Luis A. Rodríguez-Del-Bosque; Primitivo Caballero; Trevor Williams. 2018. "Acquisition of lethal infection, hypermobility and modified climbing behavior in nucleopolyhedrovirus infected larvae of Anticarsia gemmatalis." Biological Control 125, no. : 90-97.
Bacillus cereus is a gram-positive, spore-forming bacterium possessing an important and historical record as a human-pathogenic bacterium. However, several strains of this species exhibit interesting potential to be used as plant growth-promoting rhizobacteria. Here, we report the draft genome sequence of B. cereus strain CITVM-11.1, which consists of 37 contig sequences, accounting for 5,746,486 bp (with a GC content of 34.8%) and 5,752 predicted protein-coding sequences. Several of them could potentially be involved in plant-bacterium interactions and may contribute to the strong antagonistic activity shown by this strain against the charcoal root rot fungus, Macrophomina phaseolina. This genomic sequence also showed a number of genes that may confer this strain resistance against several polluting heavy metals and for the bioconversion of mycotoxins.
Javier Caballero; Cecilia Peralta; Antonella Molla; Eleodoro E. Del Valle; Primitivo Caballero; Colin Berry; Verónica Felipe; Pablo Yaryura; Leopoldo Palma. Draft Genome Sequence of Bacillus cereus CITVM-11.1, a Strain Exhibiting Interesting Antifungal Activities. Journal of Molecular Microbiology and Biotechnology 2018, 28, 47 -51.
AMA StyleJavier Caballero, Cecilia Peralta, Antonella Molla, Eleodoro E. Del Valle, Primitivo Caballero, Colin Berry, Verónica Felipe, Pablo Yaryura, Leopoldo Palma. Draft Genome Sequence of Bacillus cereus CITVM-11.1, a Strain Exhibiting Interesting Antifungal Activities. Journal of Molecular Microbiology and Biotechnology. 2018; 28 (1):47-51.
Chicago/Turabian StyleJavier Caballero; Cecilia Peralta; Antonella Molla; Eleodoro E. Del Valle; Primitivo Caballero; Colin Berry; Verónica Felipe; Pablo Yaryura; Leopoldo Palma. 2018. "Draft Genome Sequence of Bacillus cereus CITVM-11.1, a Strain Exhibiting Interesting Antifungal Activities." Journal of Molecular Microbiology and Biotechnology 28, no. 1: 47-51.
Understanding the molecular mechanisms underpinning the ecological success of plant pathogens is critical to develop strategies for controlling diseases and protecting crops. Recent observations have shown that plant pathogenic bacteria, particularly Pseudomonas, exist in a range of natural environments away from their natural plant host e.g., water courses, soil, non-host plants. This exposes them to a variety of eukaryotic predators such as nematodes, insects and amoebae present in the environment. Nematodes and amoeba in particular are bacterial predators while insect herbivores may act as indirect predators, ingesting bacteria on plant tissue. We therefore postulated that bacteria are probably under selective pressure to avoid or survive predation and have therefore developed appropriate coping mechanisms. We tested the hypothesis that plant pathogenic Pseudomonas syringae are able to cope with predation pressure and found that three pathovars show weak, but significant resistance or toxicity. To identify the gene systems that contribute to resistance or toxicity we applied a heterologous screening technique, called Rapid Virulence Annotation (RVA), for anti-predation and toxicity mechanisms. Three cosmid libraries for P. syringae pv. aesculi, pv. tomato and pv. phaseolicola, of approximately 2000 cosmids each, were screened in the susceptible/non-toxic bacterium Escherichia coli against nematode, amoebae and an insect. A number of potential conserved and unique genes were identified which included genes encoding haemolysins, biofilm formation, motility and adhesion. These data provide the first multi-pathovar comparative insight to how plant pathogens cope with different predation pressures and infection of an insect gut and provide a foundation for further study into the function of selected genes and their role in ecological success.
Federico Dorati; Glyn A. Barrett; Maria Sanchez-Contreras; Tanya Arseneault; Mateo San José; David J. Studholme; Jesús Murillo; Primitivo Caballero; Nicholas R. Waterfield; Dawn L. Arnold; Liz J. Shaw; Robert W. Jackson. Coping with Environmental Eukaryotes; Identification of Pseudomonas syringae Genes during the Interaction with Alternative Hosts or Predators. Microorganisms 2018, 6, 32 .
AMA StyleFederico Dorati, Glyn A. Barrett, Maria Sanchez-Contreras, Tanya Arseneault, Mateo San José, David J. Studholme, Jesús Murillo, Primitivo Caballero, Nicholas R. Waterfield, Dawn L. Arnold, Liz J. Shaw, Robert W. Jackson. Coping with Environmental Eukaryotes; Identification of Pseudomonas syringae Genes during the Interaction with Alternative Hosts or Predators. Microorganisms. 2018; 6 (2):32.
Chicago/Turabian StyleFederico Dorati; Glyn A. Barrett; Maria Sanchez-Contreras; Tanya Arseneault; Mateo San José; David J. Studholme; Jesús Murillo; Primitivo Caballero; Nicholas R. Waterfield; Dawn L. Arnold; Liz J. Shaw; Robert W. Jackson. 2018. "Coping with Environmental Eukaryotes; Identification of Pseudomonas syringae Genes during the Interaction with Alternative Hosts or Predators." Microorganisms 6, no. 2: 32.