Nitrosothiols in the immune system: Signaling and protection

Antioxidants and Redox Signaling 18.3 (2013): 288-308Significance: In the immune system, nitric oxide (NO) has been mainly associated with antibacterial defenses exerted through oxidative, nitrosative, and nitrative stress and signal transduction through cyclic GMP-dependent mechanisms. However, S-nitrosylation is emerging as a post-translational modification (PTM) involved in NO-mediated cell signaling. Recent Advances: Precise roles for S-nitrosylation in signaling pathways have been described both for innate and adaptive immunity. Denitrosylation may protect macrophages from their own S-nitrosylation, while maintaining nitrosative stress compartmentalized in the phagosomes. Nitrosothiols have also been shown to be beneficial in experimental models of autoimmune diseases, mainly through their role in modulating T-cell differentiation and function. Critical Issues: Relationship between S-nitrosylation, other thiol redox PTMs, and other NO-signaling pathways has not been always taken into account, particularly in the context of immune responses. Methods for assaying S-nitrosylation in individual proteins and proteomic approaches to study the S-nitrosoproteome are constantly being improved, which helps to move this field forward. Future Directions: Integrated studies of signaling pathways in the immune system should consider whether S-nitrosylation/denitrosylation processes are among the PTMs influencing the activity of key signaling and adaptor proteins. Studies in pathophysiological scenarios will also be of interest to put these mechanisms into broader contexts. Interventions modulating nitrosothiol levels in autoimmune disease could be investigated with a view to developing new therapiesFinanced by the Spanish Government grants CSD2007-00020 (RosasNet, Consolider-Ingenio 2010 programme), CP07/00143 (Miguel Servet programme), and PS09/00101; and PI10/0213

Bases de la resistencia a preparados bioinsecticidas basados en "Bacillus thuringiensis" en diferentes especies de insectos

El empleo de insecticidas en la agricultura moderna resulta fundamental para obtener unos niveles óptimos de productividad. Actualmente se tiende al empleo de bioinsecticidas dados los efectos perniciosos de la mayor parte de los insecticidas convencionales. Los preparados bioinsecticidas basados en las proteínas cristalinas insecticidas (toxinas Cry) de “Bacillus thuringiensis” (Bt) son los de mayor venta del mercado y las plantas transgénicas protegidas por estas proteínas, están siendo cultivadas a escala mundial. La vida útil de este bioinsecticida podría verse limitada por la aparición de poblaciones de insectos resistentes si no se adoptan las medidas oportunas de manejo de resistencia, siendo para ello fundamental el conocimiento de los recursos de resistencia de los insectos. El modo de acción de las toxinas Cry es un proceso complejo que incluye numerosas etapas, entre las que destaca como clave la unión a receptores específicos en la membrana epitelial de las células del intestino. La disrupción en algún punto de este proceso puede originar resistencia. Dentro de la resistencia a cada toxina Cry, pueden haber diferentes mecanismos que la produzcan, por tanto una cepa de un insecto con un tipo de resistencia puede tener un mecanismo concreto de resistencia frente a una o varias proteínas Cry tóxicas. Los genes responsables de la resistencia en varias cepas de una especie de insecto, con un mismo tipo de resistencia, pueden ser diferentes. Es por ello la importancia del estudio de los genes implicados en la interacción con las toxinas Cry, así como las proteínas para las que codifican, con el fin de poder averiguar su implicación y poder desarrollar los planes adecuados para poder manejar la aparición de resistencias como en su prevención. En el presente proyecto se pretende estudiar varios fenotipos de resistencia. Cada fenotipo consiste en una o más poblaciones de insectos de una especie que presente como característica común ser resistentes a una o más toxinas Cry. Dentro de un fenotipo se investigarán si sus bases bioquímicas y fisiológicas son únicas y comunes entre las diferentes poblaciones. En los fenotipos de resistencia en los que se hayan localizado sus bases moleculares, se determinarán los genes implicados. Se pretende establecer si estos aspectos son comunes entre las diferentes poblaciones del insecto plaga “Plutella xylostella” (primer insecto plaga que ha desarrollado resistencia a las toxinas Cry en campo) y en el insecto modelo “Bombyx mori” (lepidóptero empleado como modelo genético). Este estudio contribuirá a un mayor conocimiento de cómo retrasar, o incluso evitar, la aparición de la resistencia a Bt.The use of pesticides in modern agriculture is essential for optimum productivity. Currently, there is a tendency to use bio-insecticides since the harmful effects of most conventional insecticides. The bioinsecticide preparations based in insecticidal crystal protein (Cry toxins) of “Bacillus thuringiensis” (Bt) are the leading product in the insecticide market and Bt transgenic plants are being cultivated worldwide. The usefulness of this biopesticide could be limited by the development of resistant insect populations without appropriate resistance management measures, so knowledge of insect resistance mechanisms is essential. The Cry toxins mode of action is a complex process including several steps. The main step is the binding of the cry toxins to specific receptor located in the plasmatic membrane of midgut epithelial cells. Disruption of one of them could lead to development resistant insects. Resistance to one Cry toxin can be produced by different mechanisms in diverse insect species; therefore a resistant insect strain can have a specific mechanism of resistance to one or more toxic Cry proteins. The genes responsible of resistance in several strains of the same insect species, with the same kind of resistance, can be different. Then, is really important the study both the genes implicated on the interaction with Cry toxins and the nature of the proteins codified. The objective is to know its implication for designing the right management to avoid and prevent the development of Bt resistance. In this dissertation it has been studied various phenotypes of resistance in different strains of “Plutella xylostella” (first Bt resistant pest insect in field) and “Bombyx mori” (lepidopteran genetic model insect) insect species. In each of them the genetic and biochemical bases of resistance has been studied; as well as it has been determined the genes implicated in the resistance phenotype by linkage analysis. This study will contribute to a better understanding of the resistance and how to delay, or even prevent, the resistance to Bt

Nitrosothiols in the immune system: Signaling and protection

Significance: In the immune system, nitric oxide (NO) has been mainly associated with antibacterial defenses exerted through oxidative, nitrosative, and nitrative stress and signal transduction through cyclic GMP-dependent mechanisms. However, S-nitrosylation is emerging as a post-translational modification (PTM) involved in NO-mediated cell signaling. Recent Advances: Precise roles for S-nitrosylation in signaling pathways have been described both for innate and adaptive immunity. Denitrosylation may protect macrophages from their own S-nitrosylation, while maintaining nitrosative stress compartmentalized in the phagosomes. Nitrosothiols have also been shown to be beneficial in experimental models of autoimmune diseases, mainly through their role in modulating T-cell differentiation and function. Critical Issues: Relationship between S-nitrosylation, other thiol redox PTMs, and other NO-signaling pathways has not been always taken into account, particularly in the context of immune responses. Methods for assaying S-nitrosylation in individual proteins and proteomic approaches to study the S-nitrosoproteome are constantly being improved, which helps to move this field forward. Future Directions: Integrated studies of signaling pathways in the immune system should consider whether S-nitrosylation/denitrosylation processes are among the PTMs influencing the activity of key signaling and adaptor proteins. Studies in pathophysiological scenarios will also be of interest to put these mechanisms into broader contexts. Interventions modulating nitrosothiol levels in autoimmune disease could be investigated with a view to developing new therapies. © 2013, Mary Ann Liebert, Inc.Spanish Government (CSD2007-00020); (RosasNet, Consolider-Ingenio 2010 programme); CP07/00143 (Miguel Servet programme); PS09/00101; PI10/02136Peer Reviewe

Evaluation of thermally-treated wood of beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) against Mediterranean termites (Reticulitermes spp.)

[EN] Termite resistance of thermally-treated ash (Fraxinus excelsior L) and European beech (Fagus sylvatica L) against subterranean termites (Reticulitermes banyulensis) was evaluated. A laboratory no-choice feeding test following the standard EN 177 was performed to assess the efficacy of this thermo-modification against subterranean termites in the Mediterranean area. After 8 weeks period of exposure, results showed that durability against termites was slightly improved for thermally-treated beech wood, which was classified as moderately durable. However, in case of thermally-treated ash wood, samples were highly biodegraded by termites, revealing no increase in their durability and being classified as non durable. Guardar / Salir Siguiente >Oliver Villanueva, JV.; Gascón Garrido, P.; Ibiza Palacios, MDS. (2013). Evaluation of thermally-treated wood of beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) against Mediterranean termites (Reticulitermes spp.). European Journal of Wood and Wood Products. 71(3):391-393. doi:10.1007/s00107-013-0687-2S391393713Doi S, Kurimoto Y, Ohmura W, Ohara S, Aoyama M, Yoshimura T (1999) Effects of heat treatments of wood on the feeding behaviour of two subterranean termites. Holzforsch 53(3):225–229Hill CAS (2006) Wood modification: chemical, thermal and other processes. John Wiley & Sons, Ltd, Chichester, ISBN:9780470021729Mburu F, Dumarcay S, Huber F, Pétrissans M, Gérardin P (2007) Evaluation of thermally modified Grevillea robusta heartwood as an alternative to shortage of wood resource in Kenya: characterisation of physicochemical properties and improvement of bio-resistance. Bioresour Technol 98(18):3478–3486Militz H (2002) Heat treatment technologies in Europe: scientific background and technological state-of-art. In: 33rd annual meeting, The international research group on wood preservation, CardiffNunes L, Nobre T, Rapp AO (2004) Thermally modified wood in choice tests with subterranean termites. COST E37, ReinbeckShi JL, Kocaefe D, Amburgey T, Zhang JL (2007) A comparative study on brown-rot fungus decay and subterranean termite resistance of thermally-modified and ACQ-C-treated wood. Holz Roh- Werkst 65:353–358Surini T, Charrier F, Malvestio J, Charrier B, Moubarik A, Castéra P, Grelier S (2012) Physical properties and termite durability of maritime pine Pinus pinaster Ait., heat-treated under vacuum pressure. Wood Sci Technol 46:487–501Unsal O, Kartal SN, Candan Z, Arango RA, Clausen CA, Green F (2009) Decay and termite resistance, water absorption and swelling of thermally compressed wood panels. Int Biodeterior Biodegrad 63:548–55

Taxonomy and genetic diversity of domesticated Capsicum species in the Andean region. Genet Resour Crop

The Capsicum genus is native to tropical America and consists of 27 species, five of which are used as fresh vegetables and spices: Capsicum annuum L., Capsicum chinense Jacq., Capsicum frutescens L., Capsicum baccatum L. and Capsicum pubescens R. et P. The study of the relationships among species of cultivate Capsicum species will be useful for breeding new cultivars or hybrids. This study is focused on the genetic diversity and relationships of these species that were collected in the Andean region. Ten microsatellites and four AFLP combinations were used to characterize 260 Capsicum accessions. The AFLP tree turned out to be informative regarding relationships among species. The data clearly showed the close relationships between C. chinense and C. frutescens. Moreover, C. cardenasii and C. eximium were indistinguishable as a single, morphologically variable species. Our data showed C. baccatum and C. praetermissum to be distinct species that form a compact group. In the present work, AFLP fingerprinting indicated that C. chacoense was placed in the C. baccatum complex and showed C. tovarii as a separate species. In addition, SSR data indicated that there is intraspecific differentiation in the species C. chinense, C. baccatum and C. pubescens, as the PCoA-based clustering showed a clear geographic division related to country. Even though Bolivia is considered to be the nuclear area for these species, we have found similar variability in Ecuador and Peru for several Capsicum species. © 2011 Springer Science+Business Media B.V.VPI is the recipient of an FPU fellowship of the Ministerio de Educacion y Ciencia. We want to recognize the invaluable task carried out by the Instituto de Conservacion y Mejora de la Agrodiversidad Valenciana (COMAV, Spain), the Universidad Nacional de Loja (UNL, Ecuador), the Universidad Nacional de Piura (UNP, Peru), the Universidad Nacional Agraria La Molina (UNAM, Peru), the Universidad Nacional de Trujillo (UNT, Peru), the Universidad Nacional Pedro Ruiz Gallo (UNPRG, Peru), the Universidad Mayor de San Simon (UMSS, Bolivia), the United States Department of Agriculture (USDA, USA), the Center for Genetic Resources (CGN, The Netherlands) and the Radboud University of Nijmegen (RUN, The Netherlands), which provided important accessions. The help of Joshua Bergen in improving the English of this manuscript is gratefully acknowledged.Ibiza Gimeno, VP.; Blanca Postigo, JM.; Cañizares Sales, J.; Nuez Viñals, F. (2012). Taxonomy and genetic diversity of domesticated Capsicum species in the Andean region. Genet Resour Crop. Genetic Resources and Crop Evolution. 59(6):1077-1088. doi:10.1007/s10722-011-9744-zS10771088596Aguilar-Melendez A, Morrell PL, Mikeal LR, Seung Chul K (2009) Genetic diversity and structure in semiwild and domesticated chiles (Capsicum annuum; Solanaceae) from Mexico. Am J Bot 96:1190–1202Belkhir K, Borsa P, Chikhi L, Rafaste N, Bonhomme T (1996) Genetix 4.04 Logiciel sours Windous TM pour la genetique des populations. Laboratoire Génome, populations, interactions, Université de Montpellier II, Montpellier. Website http://www.genetix.univ-montp2.fr/genetix/genetix.htmBenham J, Jeung JU, Jasieniuk M, Kanazin V, Blake T (1999) Genographer: a graphical tool for automated AFLP and microsatellite analysis. J Agric Genomics 4:3Blanca JM, Prohens J, Anderson GJ, Zuriaga E, Canizares J, Nuez F (2007) AFLP and DNA sequence variation in an Andean domesticate, pepino (Solanum muricatum, Solanaceae): Implications for evolution and domestication. Am J Bot 94:1219–1229Bornet B, Goraguer F, Joly G, Branchard M (2002) Genetic diversity in European and Argentinian cultivated potatoes (Solanum tuberosum subsp. tuberosum) detected by inter-simple sequence repeats (ISSRs). Genome 45:481–484Bosland PW, Votava EJ (2000) Peppers: vegetable and spice capsicums. CAB International, WallingfordCavalli-Sforza LL, Edwards AWF (1967) Phylogenetic analysis: models and estimation procedures. Evolution 32:550–570Choong CY (1998) DNA polymorphisms in the study of relationships and evolution in Capsicum. Ph.D. Thesis, University of ReadingCrosby KM (2008) Pepper. In: Prohens J, Nuez F, Carena MJ (eds) Vegetables II, 1st edn. Springer, New York, pp 221–248De Swart EAM (2007) Potential for breeding sweet pepper adapted to cooler growing conditions. A physiological and genetic analysis of growth traits in Capsicum. Ph.D. Thesis, Wageningen UniversityDeWitt D, Bosland PW (1996) Peppers of the world: an identification guide. Ten Speed Press, BerkeleyDoyle JJ, Doyle JL (1990) Isolation of plant DNA from fresh tissue. Focus 12:13–15Eshbaugh WH (1976) Genetic and biochemical systematic studies of chili peppers (Capsicum-Solanaceae). Bull Torrey Bot Club 102:396–403Fery RL, Thies JA (1997) Evaluation of Capsicum chinense Jacq. cultigens for resistance to the southern root-knot nematode. Hortscience 32:923–926Furini A, Wunder J (2004) Analysis of eggplant (Solanum melongena)-related germplasm: morphological and AFLP data contribute to phylogenetic interpretations and germplasm utilization. Theor Appl Genet 108:197–208Geleta LF, Labuschagne MT, Viljoen CD (2005) Genetic variability in pepper (Capsicum annuum L.) estimated by morphological data and Amplified Fragment Length Polymorphism markers. Biodivers Conserv 14:2361–2375Guzman FA, Ayala H, Azurdia C, Duque MC, de Vicente MC (2005) AFLP assessment of genetic diversity of Capsicum genetic resources in Guatemala: home gardens as an option for conservation. Crop Sci 45:363–370Hanacek P, Vyhnanek T, Rohrer M, Cieslarova J, Stavelikova H (2009) DNA polymorphism in genetic resources of red pepper using microsatellite markers. Horticul Sci 36:127–132Ibiza VP, Canizares J, Nuez F (2010) EcoTILLING in Capsicum species: searching for new virus resistances. BMC Genomics 11:631Ince AG, Karaca M, Onus AN (2010) Genetic relationships within and between Capsicum species. Biochem Genet 48:83–95Langella O (2002) Populations 1.2.28, population genetic software. CNRS Website http://www.bioinformatics.org/~tryphon/populations/Lefebvre V, Goffinet B, Chauvet JC, Caromel B, Signoret P, Brand R, Palloix A (2001) Evaluation of genetic distances between pepper inbred lines for cultivar protection purposes: comparison of AFLP, RAPD and phenotypic data. Theor Appl Genet 102:741–750Li YC, Korol AB, Fahima T, Nevo E (2004) Microsatellites within genes: structure, function, and evolution. Mol Biol Evol 21:991–1007Loaiza-Figueroa F, Ritland K, Laborde-Cancino JA, Tanksley SD (1989) Patterns of genetic variation of the genus Capsicum (Solanaceae) in Mexico. Plant Syst Evol 165:159–188Louette D, Charrier A, Berthaud J (1997) In situ conservation of maize in Mexico: genetic diversity and maize seed management in a traditional community. Econ Bot 51:20–38McLeod MJ, Eshbaugh WH, Guttman SI (1979a) A pre-liminary biochemical systematic study of the genus Capsicum-Solanaceae. In: Hawkes JG, Lester RN, Skelding AD (eds) The biology and taxonomy of the Solanaceae. Academic Press, New York, pp 701–714McLeod MJ, Eshbaugh WH, Guttman SI (1979b) Electrophoretic study of Capsicum (Solanaceae)—purple flowered taxa. Bull Torrey Bot Club 106:326–333McLeod MJ, Guttman SI, Eshbaugh WH (1982) Early evolution of chili peppers (Capsicum). Econ Bot 36:361–368McLeod MJ, Guttman SI, Eshbaugh WH, Rayle RE (1983) An electrophoretic study of evolution in Capsicum (Solanaceae). Evolution 37:562–574Minamiyama Y, Tsuro M, Hirai M (2006) An SSR-based linkage map of Capsicum annuum. Mol Breed 18:157–169Moscone EA, Baranyi M, Ebert I, Greilhuber J, Ehrendorfer F, Hunziker AT (2003) Analysis of nuclear DNA content in Capsicum (Solanaceae) by flow cytometry and Feulgen densitometry. Ann Bot 92:21–29Moscone EA, Scaldaferro MA, Grabiele M, Cecchini NM, Garcia YS, Jarret R, Davina JR, Ducasse DA, Barboza GE, Ehrendorfer F (2007) The evolution of chili peppers (Capsicum—Solanaceae): a cytogenetic perspective. In: Proceedings of the VIth international Solanaceae conference. Solanaceae VI: Genomics Meets Biodiversity, pp 137–169Nuez F, Gil R, Costa J (1996) El cultivo de pimientos, chiles y ajies. Mundi-Prensa, MadridNuez F, Prohens J, Blanca JM (2004) Relationships origin, and diversity of Galapagos tomatoes: implications for the conservation of natural populations. Am J Bot 91:86–99Onus AN, Pickersgill B (2004) Unilateral incompatibility in Capsicum (Solanaceae): occurrence and taxonomic distribution. Ann Bot 94:289–295Pickersgill B (1971) Relationships between weedy and cultivated forms in some species of chili peppers (genus Capsicum). Evolution 25:683–691Pickersgill B (1988) The genus Capsicum: a multidisciplinary approach to the taxonomy of cultivated and wild plants. Biologisches Zentralblatt 107:381–389Pickersgill B (1991) Cytogenetics and evolution of Capsicum L. In: Tsuchiya T, Gupta PK (eds) Chromosome engineering in plants: genetics, breeding, evolution. Elsevier, Amsterdam, pp 139–160Pickersgill B (2007) Domestication of plants in the Americas: insights from Mendelian and molecular genetics. Ann Bot 100:925–940Polston JE, Cohen L, Sherwood TA, Ben-Joseph R, Lapidot M (2006) Capsicum species: symptomless hosts and reservoirs of Tomato yellow leaf curl virus. Phytopathology 96:447–452Portis E, Nagy I, Sasvari Z, Stagel A, Barchi L, Lanteri S (2007) The design of Capsicum spp. SSR assays via analysis of in silico DNA sequence, and their potential utility for genetic mapping. Plant Sci 172:640–648R Development Core Team (2007) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Website http://www.r-project.org/Rodriguez JM, Berke T, Engle L, Nienhuis J (1999) Variation among and within Capsicum species revealed by RAPD markers. Theor Appl Genet 99:147–156Ryzhova NN, Kochieva EZ (2004) Analysis of microsatellite loci of the chloroplast genome in the genus Capsicum (pepper). Russian J Genet 40:892–896Sifres A, Blanca J, Nuez F (2010) Pattern of genetic variability of Solanum habrochaites in its natural area of distribution. Genet Resour Crop Evol. doi: 10.1007/s10722-010-9578-0Spooner DM, McLean K, Ramsay G, Waugh R, Bryan GJ (2005) A single domestication for potato based on multilocus amplified fragment length polymorphism genotyping. Proc Natl Acad Sci USA 102:14694–14699Sudre CP, Goncalves LSA, Rodrigues R, do Amaral AT, Riva-Souza EM, Bento CD (2010) Genetic variability in domesticated Capsicum spp. as assessed by morphological and agronomic data in mixed statistical analysis. Genet Mol Res 9:283–294Tam SM, Lefebvre V, Palloix A, Sage-Palloix AM, Mhiri C, Grandbastien MA (2009) LTR-retrotransposons Tnt1 and T135 markers reveal genetic diversity and evolutionary relationships of domesticated peppers. Theor Appl Genet 119:973–989Tong N, Bosland PW (1999) Capsicum tovarii, a new member of the Capsicum baccatum complex. Euphytica 109:71–77Toquica SP, Rodriguez F, Martinez E, Duque MC, Tohme J (2003) Molecular characterization by AFLPs of Capsicum germplasm from the Amazon Department in Colombia, characterization by AFLPs of Capsicum. Genet Resour Crop Evol 50:639–647Walsh BM, Hoot SB (2001) Phylogenetic relationships of Capsicum (Solanaceae) using DNA sequences from two noncoding regions: the chloroplast atpB-rbcL spacer region and nuclear waxy introns. Int J Plant Sci 162:1409–1418Yoon JB, Yang DC, Do JW, Park HG (2006) Overcoming two post-fertilization genetic barriers in interspecific hybridization between Capsicum annuum and Capsicum baccatum for introgression of anthracnose resistance. Breeding Sci 56:31–38Zewdie Y, Bosland PW (2000) Capsaicinoid inheritance in an interspecific hybridization of Capsicum annuum × C. chinense. J Am Soc Hortic Sci 125:448–453Zijlstra S, Purimahu AC, Lindhout P (1991) Pollen tube growth in interspecific crosses between Capsicum species. HortScience 26:585–586Zuriaga E, Blanca J, Nuez F (2009a) Classification and phylogenetic relationships in Solanum section Lycopersicon based on AFLP and two nuclear gene sequences. Genet Resour Crop Evol 56:663–678Zuriaga E, Blanca JM, Cordero L, Sifres A, Blas-Cerdan WG, Morales R, Nuez F (2009b) Genetic and bioclimatic variation in Solanum pimpinellifolium. Genet Resour Crop Evol 56:39–5

Genetic and Biochemical Characterization of Field-Evolved Resistance to Bacillus thuringiensis Toxin Cry1Ac in the Diamondback Moth, Plutella xylostella

The long-term usefulness of Bacillus thuringiensis Cry toxins, either in sprays or in transgenic crops, may be compromised by the evolution of resistance in target insects. Managing the evolution of resistance to B. thuringiensis toxins requires extensive knowledge about the mechanisms, genetics, and ecology of resistance genes. To date, laboratory-selected populations have provided information on the diverse genetics and mechanisms of resistance to B. thuringiensis, highly resistant field populations being rare. However, the selection pressures on field and laboratory populations are very different and may produce resistance genes with distinct characteristics. In order to better understand the genetics, biochemical mechanisms, and ecology of field-evolved resistance, a diamondback moth (Plutella xylostella) field population (Karak) which had been exposed to intensive spraying with B. thuringiensis subsp. kurstaki was collected from Malaysia. We detected a very high level of resistance to Cry1Ac; high levels of resistance to B. thuringiensis subsp. kurstaki Cry1Aa, Cry1Ab, and Cry1Fa; and a moderate level of resistance to Cry1Ca. The toxicity of Cry1Ja to the Karak population was not significantly different from that to a standard laboratory population (LAB-UK). Notable features of the Karak population were that field-selected resistance to B. thuringiensis subsp. kurstaki did not decline at all in unselected populations over 11 generations in laboratory microcosm experiments and that resistance to Cry1Ac declined only threefold over the same period. This finding may be due to a lack of fitness costs expressed by resistance strains, since such costs can be environmentally dependent and may not occur under ordinary laboratory culture conditions. Alternatively, resistance in the Karak population may have been near fixation, leading to a very slow increase in heterozygosity. Reciprocal genetic crosses between Karak and LAB-UK populations indicated that resistance was autosomal and recessive. At the highest dose of Cry1Ac tested, resistance was completely recessive, while at the lowest dose, it was incompletely dominant. A direct test of monogenic inheritance based on a backcross of F(1) progeny with the Karak population suggested that resistance to Cry1Ac was controlled by a single locus. Binding studies with (125)I-labeled Cry1Ab and Cry1Ac revealed greatly reduced binding to brush border membrane vesicles prepared from this field population

Valuation of the Treatments of Consolidation of Wood Deterioration Comparing the Values of the Elasticity Amounts Before and After the Treatment

Esta investigación se planteó con el objetivo de mensurar el incremento de la resistencia a la flexión (MOE) en maderas deterioradas sometidas a consolidación con dos resinas termoplásticas: poli metil metacrilato (MMA) y polivinil butiral (PVB). Ambas resinas se aplicaron por inmersión a dos presiones diferentes 0,5atm y 1,0atm. Para aplicar las resinas a 0,5atm se empleó una cámara experimental de vacío. Todos los procesos se realizaron bajo temperatura y humedad relativa constantes. Las probetas empleadas corresponden a una única especie de madera (aliso) y presentaban diferente grado de infestación por organismos xilófagos. Los grados de infestación se agruparon previamente de forma natural en tres grupos correspondiente a niveles de infestación leve, medio o severo. El equipo empleado se basa en medir la frecuencia con que vibra libremente un objeto, frecuencia Eigen; esta técnica está clasificada como no destructiva. Partiendo de los valores de frecuencia, es factible obtener el módulo de elasticidad dinámico (MOEdin) de las probetas tratadas. Los MOEdin de las probetas tratadas con MMA o PVB, no muestran diferencias importantes o significativas. Sin embargo, se evideió cierta tendencia a que los valores de MOEdin de probetas tratadas con PVB sean mayores a aquellos de probetas tratadas con MMA. Todo el grupo de probetas tratadas presentó valores de MOEdin mayores a las probetas testigo, sin embargo esta diferencia no es estadísticamente significativa. Concluyéndose que si bien hay un incremento en el módulo de elasticidad (y en consecuencia en la resistencia de las maderas) este no difiere estadísticamente de las probetas sin consolidar.This study aims to measure the increase of the resistance of the flexion (MOE) in deteriorated wood subjected to consolidation with two thermoplastic resins: poly methyl methacrylate (MMA) and polyvinylbutyral (PVB). Both resins are applied for the immersion of two different pressures 0, 5 atm and 1, 0 atm. In order to apply the resins to 0, 5 atm a vacuum experimental camera is used. All the processes are established at relative constant temperature and humidity. The beakers used correspond to a unique type of wood (alder) and represent a different grade of infestation from woodworm. The grades of infestation are previously grouped in a natural way with three groups referring to the level of infestation: light, medium and severe. The working equipment is based on the measuring the frequency involving a freely vibrating object - the frequency Eigen. This technique is classified as not being destructive. Starting with the frequency values, it is feasible to obtain the module of dynamic elasticity (MOE din) from the treated beakers. The MOE din from the treated beakers with MMA or PVB do not show considerable nor important differences. However, a certain tendency is noticed that the MOE din values from the beakers treated with PVB tend to be higher than those treated with MMA. The whole group of treated beakers showed higher MOE din values than the other beakers, but the difference noted is not statistically significant. To sum up, even if there is an increase in the amount of elasticity (and as a consequence in the resistance of the wood), this does not differ statistically to the beakers that have not been consolidated.Benítez Telles, JE.; Oliver Villanueva, JV.; Ibiza Palacios, MDS.; Martínez Ruiz, G.; Grafiá Sales, JV.; Vivancos Ramón, MV. (2008). Valoración de los tratamientos de consolidación de madera deteriorada comparando los valores de módulo de elasticidad antes y después de los tratamientos. Arché. (3):97-102. http://hdl.handle.net/10251/3175497102

Common, but complex, mode of resistance of Plutella xylostella to Bacillus thuringiensis toxins Cry1Ab and Cry1Ac

A field collected population of Plutella xylostella (SERD4) was selected in the laboratory with Bacillus thuringiensis endotoxins Cry1Ac (Cry1Ac-SEL) and Cry1Ab (Cry1Ab-SEL). Both subpopulations showed similar phenotypes: high resistance to the Cry1A toxins and little cross-resistance to Cry1Ca or Cry1D. A previous analysis of the Cry1Ac-SEL showed incompletely dominant resistance to Cry1Ac with more than one factor, at least one of which was sex influenced. In the present study reciprocal mass crosses between Cry1Ab-SEL and a laboratory susceptible population (ROTH) provided evidence that Cry1Ab resistance was also inherited as incompletely dominant trait with more than one factor, and at least one of the factors was sex influenced. Analysis of single pair mating indicated that Cry1Ab-SEL was still heterogeneous for Cry1Ab resistance genes, showing genes with different degrees of dominance. Binding studies showed a large reduction of specific binding of Cry1Ab and Cry1Ac to midgut membrane vesicles of the Cry1Ab-SEL subpopulation. Cry1Ab-SEL was found to be more susceptible to trypsin-activated Cry1Ab toxin than protoxin, although no defect in toxin activation was found. Present and previous results indicate a common basis of resistance to both Cry1Ab and Cry1Ac in selected subpopulations and suggest that a similar set of resistance genes are responsible for resistance to Cry1Ab and Cry1Ac and are selected whichever toxin was used. The possibility of an incompletely dominant trait of resistant to these toxins should be taken into account when considering refuge resistance management strategies