Browsing by Author "Palma Dovis, Leopoldo"

Now showing 1 - 17 of 17
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    PublicationOpen Access
    Analysis of a naturally-occurring deletion mutant of Spodoptera frugiperda multiple nucleopolyhedrovirus reveals sf58 as a new per os infectivity factor of lepidopteran-infecting baculoviruses
    (Elsevier, 2012-10-21) Simón de Goñi, Oihane; Palma Dovis, Leopoldo; Williams, Trevor; López Ferber, Miguel; Caballero Murillo, Primitivo; Producción Agraria; Nekazaritza Ekoizpena; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua
    The Nicaraguan population of Spodoptera frugiperda multiple nucleopolyhedrovirus, SfMNPV-NIC, is structured as a mixture of nine genotypes (A–I). Occlusion bodies (OBs) of SfMNPV-C, -D and -G pure genotypes are incapable of oral transmission; a phenotype which in SfMNPV-C and -D is due to the absence of pif1 and pif2 genes. The complete sequence of the SfMNPV-G genome was determined to identify possible factors involved in this phenotype. Deletions of 4860 bp (22,366–27,225) and 60 bp (119,759–119,818) were observed in SfMNPV-G genome compared with that of the predominant complete genotype SfMNPV-B (132,954 bp). However no genes homologous to previously described per os infectivity factors were located within the deleted sequences. Significant differences were detected in the nucleotide sequence in sf58 gene (unknown function) that produced changes in the amino acid sequence and the predicted secondary structure of the corresponding protein. This gene is conserved only in lepidopteran baculoviruses (alpha- and betabaculoviruses). To determine the role of sf58 in peroral infectivity a deletion mutant was constructed using bacmid technology. OBs of the deletion mutant (Sf58null) were not orally infectious for S. frugiperda larvae, whereas Sf58null rescue virus OBs recovered oral infectivity. Sf58null DNA and occlusion derived virions (ODVs) were as infective as SfMNPV bacmid DNA and ODVs in intrahemocelically infected larvae or cell culture, indicating that defects in ODV or OB morphogenesis were not involved in the loss of peroral infectivity. Addition of optical brightener or the presence of the orally infectious SfMNPV-B OBs in mixtures with SfMNPV-G OBs did not recover Sf58null OB infectivity. According to these results sf58 is a new per os infectivity factor present only in lepidopteran baculoviruses.
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    PublicationOpen Access
    Bacillus thuringiensis toxins: an overview of their biocidal activity
    (MDPI, 2014) Palma Dovis, Leopoldo; Muñoz Labiano, Delia; Berry, Colin; Murillo Martínez, Jesús; Caballero Murillo, Primitivo; Nekazaritza Ekoizpena; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    Bacillus thuringiensis (Bt) is a Gram positive, spore-forming bacterium that synthesizes parasporal crystalline inclusions containing Cry and Cyt proteins, some of which are toxic against a wide range of insect orders, nematodes and human-cancer cells. These toxins have been successfully used as bioinsecticides against caterpillars, beetles, and flies, including mosquitoes and blackflies. Bt also synthesizes insecticidal proteins during the vegetative growth phase, which are subsequently secreted into the growth medium. These proteins are commonly known as vegetative insecticidal proteins (Vips) and hold insecticidal activity against lepidopteran, coleopteran and some homopteran pests. A less well characterized secretory protein with no amino acid similarity to Vip proteins has shown insecticidal activity against coleopteran pests and is termed Sip (secreted insecticidal protein). Bin-like and ETX_MTX2-family proteins (Pfam PF03318), which share amino acid similarities with mosquitocidal binary (Bin) and Mtx2 toxins, respectively, from Lysinibacillus sphaericus, are also produced by some Bt strains. In addition, vast numbers of Bt isolates naturally present in the soil and the phylloplane also synthesize crystal proteins whose biological activity is still unknown. In this review, we provide an updated overview of the known active Bt toxins to date and discuss their activities.
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    PublicationOpen Access
    Baculovirus expression and functional analysis of Vpa2 proteins from Bacillus thuringiensis
    (MDPI, 2020) Simón de Goñi, Oihane; Palma Dovis, Leopoldo; Fernández González, Ana Beatriz; Williams, Trevor; Caballero Murillo, Primitivo; Institute for Multidisciplinary Research in Applied Biology - IMAB
    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.
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    PublicationOpen Access
    Computational prediction of protein-coding gene and annotation of DNA sequences with agronomic interest in Pleurotus ostreatus (Oyster Mushroom)
    (Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2006) Palma Dovis, Leopoldo; Peñas Parrila, María Manuela; Ramírez Nasto, Lucía; Pisabarro de Lucas, Gerardo; Producción Agraria; Nekazaritza Ekoizpena
    Pleurotus ostreatus, commonly known as oyster mushroom, is a commercially important edible fungus with interesting biotechnological properties. Quantitative trait loci (QTL) analyses are rare in fungi and little is known about their number, position, and genetic structure. Previous studies of our group have allowed the construction of a genetic linkage map of P. ostreatus var. florida, which has provided the basis for performing an efficient QTL analysis. In fact, there is a region of the chromosome VII of P. ostreatus where the most QTLs related to the production and precocity characters have been mapped. These quantitative traits are presumably under the control of a polygenic genetic system and could be associated with some chromosomal regions. The hypothesis of this work is that there is a region in the chromosome VII of protoclon PC15 (monokaryotic parental of the N001 dikaryotic strain) where exist genes which are responsible for the QTLs mentioned above. In order to test this hypothesis, we are developing a molecular QTL analysis through the sequencing of a region with an approximated size of 320 Kbp in chromosome VII (protoclon PC15). For this purpose, a BAC genomic library was constructed and two BAC clones spanning the region of interest are being sequenced. To carry out an efficient computational prediction of protein-coding genes and its annotation on the partial sequences obtained up to date, we have used different Internet resources such as BLASTx, BLASTp, BLASTn, and FGENESH trained on some basidiomycetes genomic data like Phanerochaete chrysosporium and Cryptococcus neoformans (SoftBerry). To our knowledge, this is the firs molecular QTL analysis performed on this edible mushroom.
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    PublicationOpen Access
    Draft genome sequence of Bacillus thuringiensis serovar tolworthi strain Na205-3, an isolate toxic for Helicoverpa armigera
    (American Society for Microbiology, 2014) Palma Dovis, Leopoldo; Muñoz Labiano, Delia; Murillo Martínez, Jesús; Caballero Murillo, Primitivo; Nekazaritza Ekoizpena; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    We report here the complete annotated 6,510,053-bp draft genome sequence of Bacillus thuringiensis serovar tolworthi strain Na205-3, which is toxic for Helicoverpa armigera. This strain potentially contains nine insecticidal toxin genes homologous to cry1Aa12, cry1Ab1, cry1Ab8, cry1Ba1, cry1Af1, cry1Ia10, vip1Bb1, vip2Ba2, and vip3Aa6.
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    PublicationOpen Access
    Draft genome sequence of Photorhabdus luminescens strain DSPV002N isolated from Santa Fe, Argentina
    (American Society for Microbiology, 2016) Palma Dovis, Leopoldo; Valle, Eleodoro E. del; Frizzo, Laureano; Berry, Colin; Caballero Murillo, Primitivo; Nekazaritza Ekoizpena; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    Here, we report the draft genome sequence of Photorhabdus luminescens strain DSPV002N, which consists of 177 contig sequences accounting for 5,518,143 bp, with a G+C content of 42.3% and 4,701 predicted protein-coding genes (CDSs). From these, 27 CDSs exhibited significant similarity with insecticidal toxin proteins from Photorhabdus luminescens subsp. laumondii TT01.
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    PublicationOpen Access
    Draft genome sequences of two bacillus thuringiensis strains and characterization of a putative 41.9-kDa insecticidal toxin
    (MDPI, 2014) Palma Dovis, Leopoldo; Muñoz Labiano, Delia; Berry, Colin; Murillo Martínez, Jesús; Caballero Murillo, Primitivo; Nekazaritza Ekoizpena; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    In this work, we report the genome sequencing of two Bacillus thuringiensis strains using Illumina next-generation sequencing technology (NGS). Strain Hu4-2, toxic to many lepidopteran pest species and to some mosquitoes, encoded genes for two insecticidal crystal (Cry) proteins, cry1Ia and cry9Ea, and a vegetative insecticidal protein (Vip) gene, vip3Ca2. Strain Leapi01 contained genes coding for seven Cry proteins (cry1Aa, cry1Ca, cry1Da, cry2Ab, cry9Ea and two cry1Ia gene variants) and a vip3 gene (vip3Aa10). A putative novel insecticidal protein gene 1143 bp long was found in both strains, whose sequences exhibited 100% nucleotide identity. The predicted protein showed 57 and 100% pairwise identity to protein sequence 72 from a patented Bt strain (US8318900) and to a putative 41.9-kDa insecticidal toxin from Bacillus cereus, respectively. The 41.9-kDa protein, containing a C-terminal 6× HisTag fusion, was expressed in Escherichia coli and tested for the first time against four lepidopteran species (Mamestra brassicae, Ostrinia nubilalis, Spodoptera frugiperda and S. littoralis) and the green-peach aphid Myzus persicae at doses as high as 4.8 μg/cm2 and 1.5 mg/mL, respectively. At these protein concentrations, the recombinant 41.9-kDa protein caused no mortality or symptoms of impaired growth against any of the insects tested, suggesting that these species are outside the protein’s target range or that the protein may not, in fact, be toxic. While the use of the polymerase chain reaction has allowed a significant increase in the number of Bt insecticidal genes characterized to date, novel NGS technologies promise a much faster, cheaper and efficient screening of Bt pesticidal proteins.
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    PublicationOpen Access
    Genetic breeding of edible mushrooms: from the genome to the production of new varieties of Pleurotus ostreatus
    (Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2006) Pisabarro de Lucas, Gerardo; Peñas Parrila, María Manuela; Pérez Garrido, María Gumersinda; Park, Sang-Kyu; Eizmendi Goicoechea, Arantza; Parada Albarracín, Julián Andrés; Palma Dovis, Leopoldo; Idareta Olagüe, Eneko; Jurado Cabanillas, Javier; Castellón Gadea, Jordi; Ramírez Nasto, Lucía; Producción Agraria; Nekazaritza Ekoizpena
    The breeding of new varieties of industrially cultivated edible mushrooms must proceed in the framework defined by the breeding objectives, the biological characteristics of the material and the legal and cultural constraints imposed to the breeding technology to be used. This last aspect is of the greatest importance in the case of a food that is considered in European countries as high quality and closer to nature than other industrially produced foods. This fact prevents the use of genetic-engineering based technologies for breeding, as the consumers would hardly accept genetically modified mushrooms. Consequently, mushroom breeding should be based on time-consuming processes of classic breeding. Molecular biology, however, can offer to the breeders useful tools for speeding up the selection process, for evaluating the new bred lines and, last but not least, to identify and eventually protect legally the outcome of their breeding programs.
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    PublicationOpen Access
    Genome sequence analysis of native Xenorhabdus strains isolated from Entomopathogenic nematodes in Argentina
    (MDPI, 2024) Palma Dovis, Leopoldo; Frizzo, Laureano; Kaiser, Sebastian; Berry, Colin; Caballero Murillo, Primitivo; Bode, Helge B.; Valle, Eleodoro E. del; Institute for Multidisciplinary Research in Applied Biology - IMAB
    Entomopathogenic nematodes from the genus Steinernema (Nematoda: Steinernematidae) are capable of causing the rapid killing of insect hosts, facilitated by their association with symbiotic Gram-negative bacteria in the genus Xenorhabdus (Enterobacterales: Morganellaceae), positioning them as interesting candidate tools for the control of insect pests. In spite of this, only a limited number of species from this bacterial genus have been identified from their nematode hosts and their insecticidal properties documented. This study aimed to perform the genome sequence analysis of fourteen Xenorhabdus strains that were isolated from Steinernema nematodes in Argentina. All of the strains were found to be able of killing 7th instar larvae of Galleria mellonella (L.) (Lepidoptera: Pyralidae). Their sequenced genomes harbour 110 putative insecticidal proteins including Tc, Txp, Mcf, Pra/Prb and App homologs, plus other virulence factors such as putative nematocidal proteins, chitinases and secondary metabolite gene clusters for the synthesis of different bioactive compounds. Maximum-likelihood phylogenetic analysis plus average nucleotide identity calculations strongly suggested that three strains should be considered novel species. The species name for strains PSL and Reich (same species according to % ANI) is proposed as Xenorhabdus littoralis sp. nov., whereas strain 12 is proposed as Xenorhabdus santafensis sp. nov. In this work, we present a dual insight into the biocidal potential and diversity of the Xenorhabdus genus, demonstrated by different numbers of putative insecticidal genes and biosynthetic gene clusters, along with a fresh exploration of the species within this genus.
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    PublicationOpen Access
    Identificación y producción de proteínas de Bacillus thuringiensis: evaluación de su actividad insecticída
    (2014) Caballero Sánchez, Javier; Palma Dovis, Leopoldo; Matas Casado, Isabel María; Escuela Técnica Superior de Ingenieros Agrónomos; Nekazaritza Ingeniarien Goi Mailako Eskola Teknikoa
    La bacteria entomopatógena Bacillus thuringiensis (Bt) es el microorganismo más empleado actualmente como materia activa en el desarrollo de bioinsecticidas y la construcción de plantas transgénicas (planta Bt) resistentes a los insectos. Todo ello se debe a su gran capacidad para producir una enorme variedad de proteínas con elevada toxicidad contra un amplio número de especies de insectos que suelen originar importantes plagas agrícolasGforestales o de interés médicoGveterinario. En este trabajo se ha analizado el genoma de la cepa L60 de B. thuringiensis serovar ibérica (BtibGL60) con el objetivo de identificar genes que codifiquen para nuevas proteínas con potencial actividad insecticida por si mismas o una posible acción sinérgica para otras proteínas insecticidas ya descritas. El resultado más relevante ha sido la identificación de 5 nuevos genes que codifican para proteínas con similitudes del 99 %, 56 %, 44 % y 51 % a las proteínas Bel_Enhancin, Cry32Ba1, Cry66Aa2 y Vip4Aa1, previamente descritas y, en virtud de lo cual, se prevé que puedan tener actividad insecticida. Todos estos genes, excepto uno (el homólogo a vip4Aa1), se han logrado expresar, pero sólo en uno de estos casos (el homólogo a cry32Ba1) se ha conseguido obtener la proteína en fase soluble. La proteína soluble Cry32Ba1, así como las proteínas solubles que componen el cristal BtibGL60 y las que se encuentran en el sobrenadante de la fermentación de esta cepa, han sido caracterizadas mediante bioensayos para determinar su actividad insecticida. Los bioensayos cualitativos realizados contra 7 especies del orden Lepidoptera (Spodoptera littoralis, Spodoptera frugiperda, Mamestra brassicae, Chrysodeixis chalcites, Helicoverpa armigera, Ostrinia nubilalis y Lobesia botrana), una especie de Coleoptera (Leptinotarsa decemlineata) y una especie de Diptera (Ceratitis capitata) han revelado que ninguna de estas especies de insectos son susceptibles a ninguna de las proteínas evaluadas, excepto la moderada susceptibilidad mostrada por C. chalcites a la proteína Cry32Ba1 y por C. capitata a las proteínas del cristal de BtibGL60. Se discute el interés práctico y el alcance del estudio realizado dentro del campo de los bioinsecticidas microbianos
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    PublicationOpen Access
    Incidencia natural de genes vip3 en aislados de Bacillus Thuringiensis procedentes de hábitats terrestres acuáticos
    (2011) Flamarique Flamarique, Maite; Caballero Murillo, Primitivo; Palma Dovis, Leopoldo; Escuela Técnica Superior de Ingenieros Agrónomos; Nekazaritza Ingeniarien Goi Mailako Eskola Teknikoa; Producción Agraria; Nekazaritza Ekoizpena
    Bacillus thuringiensis (Bt) es el insecticida biológico más aplicado en todo el mundo. Su aislamiento y caracterización es la base de muchos programas de control de plagas en nuevos trabajos. Bt es una bacteria cosmopolita que puede ser aislada fácilmente a partir de muestras de suelo y otros muchos substratos. Su característica más importante es la capacidad de producir proteínas con toxicidad específica contra insectos . En estado vegetativo presenta unas proteínas de carácter insecticida (Vip) , las cuales son una posible alternativa para las δ - endotoxinas que actualmente se utilizan en el control de plagas y en las cuales están comenzando a surgir resistencias. La caracterización e identificación de nuevas proteínas Vip3 de Bt es interesante ya que por un lado puede contribuir a ampliar el espectro huésped de esta bacteria y por otro , disponer de alternativas en los casos de resistencia. Esta es la razón por la que en este trabajo se amplía el horizonte de uso de esta bacteria a través de la búsqueda de nuevas cepas y proteínas Vip3 . Para ello se analizó una colección de 192 cepas a partir de muestras de hábitats terrestres y acuáticos. Se emplearon varios métodos para su análisis , reacción en cadena de la polimerasa (PCR), de acuerdo a el conocimiento que se tiene sobre las regiones conservada y variable de los genes vip3 ya estudiados y el análisis PCR - RFLP (Restriction Fragment Length Polymorphism) de los fragmentos de restricción de productos de PCR amplificados con cebadores degenerados. En el estudio se encontró que el 73% de las cepas analizadas de Bt contenían un gen vip3, siendo la frecuencia de este mayor en la colección de aislados de hábitat acuático . La evaluación de los aislados dio lugar a la clonación de 8 de ellos , en los cuales se encontró un posible aislado candidato a contener un gen vip3 nuevo.
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    PublicationOpen Access
    Microencapsulación de proteínas insecticidas Vip3 de Bacillus thuringiensis
    (2014) Mañeru Oria, Francisco Javier; Palma Dovis, Leopoldo; Ruiz de Escudero Fuentemilla, Íñigo; Escuela Técnica Superior de Ingenieros Agrónomos; Nekazaritza Ingeniarien Goi Mailako Eskola Teknikoa
    Bacillus thuringiensis es el microorganismo más empleado en el desarrollo de bioinsecticidas, ya que produce proteínas con propiedades insecticidas para distintas plagas. Los objetivos de este trabajo son realizar una comparación entre dos sistemas de producción de proteína heteróloga y estudiar el efecto de la luz ultravioleta sobre la actividad insecticida de estas proteínas. En este trabajo se ha producido con éxito la proteína secretable Vip3Ag4 de B. thuringiensis en Bacillus megaterium. Además se llevó a cabo la construcción para la expresión de proteína Vip3Ag4 en Pseudomonas fluorescens. En este trabajo se ha puesto de manifiesto que el sistema de microencapsulación de B. megaterium protege a la proteína de factores abióticos como la luz UV, haciendo que la proteína mantenga su toxicidad en el tiempo tras su aplicación en campo como agente de control de plagas. La microencapsulación de proteínas abre las puertas a trabajos futuros basados en el desarrollo de bioinsecticidas a partir de proteínas Vip.
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    PublicationOpen Access
    Molecular and insecticidal characterization of a novel cry-related protein from bacillus thuringiensis toxic against Myzus persicae
    (MDPI, 2014) Palma Dovis, Leopoldo; Muñoz Labiano, Delia; Berry, Colin; Murillo Martínez, Jesús; Escudero, Iñigo de; Caballero Murillo, Primitivo; Nekazaritza Ekoizpena; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    This study describes the insecticidal activity of a novel Bacillus thuringiensis Cry-related protein with a deduced 799 amino acid sequence (~89 kDa) and ~19% pairwise identity to the 95-kDa-aphidicidal protein (sequence number 204) from patent US 8318900 and ~40% pairwise identity to the cancer cell killing Cry proteins (parasporins Cry41Ab1 and Cry41Aa1), respectively. This novel Cry-related protein contained the five conserved amino acid blocks and the three conserved domains commonly found in 3-domain Cry proteins. The protein exhibited toxic activity against the green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae) with the lowest mean lethal concentration (LC50 = 32.7 μg/mL) reported to date for a given Cry protein and this insect species, whereas it had no lethal toxicity against the Lepidoptera of the family Noctuidae Helicoverpa armigera (Hübner), Mamestra brassicae (L.), Spodoptera exigua (Hübner), S. frugiperda (J.E. Smith) and S. littoralis (Boisduval), at concentrations as high as ~3.5 μg/cm2. This novel Cry-related protein may become a promising environmentally friendly tool for the biological control of M. persicae and possibly also for other sap sucking insect pests.
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    Sequence comparison between three geographically distinct Spodoptera frugiperda multiple nucleopolyhedrovirus isolates: detecting positively selected genes
    (Elsevier, 2011-01-14) Simón de Goñi, Oihane; Palma Dovis, Leopoldo; Beperet Arive, Inés; Muñoz Labiano, Delia; López Ferber, Miguel; Caballero Murillo, Primitivo; Williams, Trevor; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    The complete genomic sequence of a Nicaraguan plaque purified Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV) genotype SfMNPV-B was determined and compared to previously sequenced isolates from United States (SfMNPV-3AP2) and Brazil (SfMNPV-19). The genome of SfMNPV-B (132,954 bp) was 1623 bp and 389 bp larger than that of SfMNPV-3AP2 and SfMNPV-19, respectively. Genome size differences were mainly due to a deletion located in the SfMNPV-3AP2 egt region and small deletions and point mutations in SfMNPV-19. Nucleotide sequences were strongly conserved (99.35% identity) and a high degree of predicted amino acid sequence identity was observed. A total of 145 open reading frames (ORFs) were identified in SfMNPV-B, two of them (sf39a and sf110a) had not been previously identified in the SfMNPV-3AP2 and SfMNPV-19 genomes and one (sf57a) was absent in both these genomes. In addition, sf6 was not previously identified in the SfMNPV-19 genome. In contrast, SfMNPV-B and SfMNPV-19 both lacked sf129 that had been reported in SfMNPV-3AP2. In an effort to identify genes potentially involved in virulence or in determining population adaptations, selection pressure analysis was performed. Three ORFs were identified undergoing positive selection: sf49 (pif-3), sf57 (odv-e66b) and sf122 (unknown function). Strong selection for ODV envelope protein genes indicates that the initial infection process in the insect midgut is one critical point at which adaptation acts during the transmission of these viruses in geographically distant populations. The function of ORF sf122 is being examined.
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    UV protection and insecticidal activity of microencapsulated Vip3Ag4 protein in Bacillus megaterium
    (Elsevier, 2024-06-17) Palma Dovis, Leopoldo; Ruiz de Escudero Fuentemilla, Íñigo; Mañeru Oria, Francisco Javier; Berry, Colin; Caballero Murillo, Primitivo; Institute for Multidisciplinary Research in Applied Biology - IMAB
    In this study, secretable Vip3Ag4 protein was encapsulated in Bacillus megaterium and used for quantitative bioassays, in order to determine the UV photoprotective capacity of the cell, for preventing inactivation of the insecticidal activity of the protein. The non-encapsulated and purified protein was exposed to the UV light showing a LC50 of 518 ng/cm2 against Spodoptera littoralis larvae, whereas the exposed encapsulated protein exhibited 479 ng/cm2. In addition to the capability to accumulate Vip3 proteins for the development of novel insecticidal formulates, the B. megaterium cell has demonstrated to provide moderate protection against the deleterious action of UV light.
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    The Vip3Ag4 insecticidal protoxin from bacillus thuringiensis adopts a tetrameric configuration that is maintained on proteolysis
    (MDPI, 2017) Palma Dovis, Leopoldo; Scott, David J.; Harris, Gemma; Din, Salah-Ud; Williams, Thomas L.; Roberts, Oliver J.; Young, Mark T.; Caballero Murillo, Primitivo; Berry, Colin; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    The Vip3 proteins produced during vegetative growth by strains of the bacterium Bacillus thuringiensis show insecticidal activity against lepidopteran insects with a mechanism of action that may involve pore formation and apoptosis. These proteins are promising supplements to our arsenal of insecticidal proteins, but the molecular details of their activity are not understood. As a first step in the structural characterisation of these proteins, we have analysed their secondary structure and resolved the surface topology of a tetrameric complex of the Vip3Ag4 protein by transmission electron microscopy. Sites sensitive to proteolysis by trypsin are identified and the trypsin-cleaved protein appears to retain a similar structure as an octomeric complex comprising four copies each of the ~65 kDa and ~21 kDa products of proteolysis. This processed form of the toxin may represent the active toxin. The quality and monodispersity of the protein produced in this study make Vip3Ag4 a candidate for more detailed structural analysis using cryo-electron microscopy.
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    PublicationOpen Access
    Vip3C, a novel class of vegetative insecticidal proteins from Bacillus thuringiensis
    (American Society for Microbiology, 2012) Palma Dovis, Leopoldo; Hernández Rodríguez, C.; Maeztu Martínez, Mireya; Hernández Martínez, Patricia; Ruiz de Escudero Fuentemilla, Íñigo; Escriche, Baltasar; Muñoz Labiano, Delia; Rie, Jeroen van; Ferré, Juan; Caballero Murillo, Primitivo; Nekazaritza Ekoizpena; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    Three vip3 genes were identified in two Bacillus thuringiensis Spanish collections. Sequence analysis revealed a novel Vip3 protein class (Vip3C). Preliminary bioassays of larvae from 10 different lepidopteran species indicated that Vip3Ca3 caused more than 70% mortality in four species after 10 days at 4 μg/cm2.