Management of Insect Pest by RNAi — A New Tool for Crop Protection

The fast-growing human population requires the development of new agricultural technologies to meet consumers´ demand, while minimizing environmental impacts. Insect pests are one of the main causes for losses in agriculture production, and current control technologies based on pesticide application or the use of transgenic crops expressing Bacillus thuringiensis toxin proteins are facing efficacy challenges. Novel approaches to control pests are urgently necessary. RNA interference (RNAi) is a gene silencing mechanism triggered by providing double-stranded RNA (dsRNA), that when ingested into insects can lead to death or affect the viability of the target pest. Transgenic plants expressing dsRNA version of insect specific target genes are the new generation of resistant plants. However, the RNAi mechanism is not conserved among insect orders, and its elucidation is the key to develop commercial RNAi crops. In this chapter, we review the core RNAi pathway in insects and the dsRNA uptake, amplification, and spread of systemic silencing signals in some key insect species. We also highlight some of the experimental steps before developing an insect-pest-resistant “RNAi plant”. Lastly, we review some of the most recent development studies to control agricultural insect pests by RNAi transgenic plants

Oral rehabilitation of the lower arch using lithium disilicate and dental implants.

Introduction: The constant search for a harmonic and aesthetic smile raises the level of demand and expectation of patients. The laminated veneers stand out as a treatment option for aesthetic rehabilitation in clinical practice as they provide more conservative procedures and mimic dental structures. The development of new ceramic systems reinforced by lithium disilicate and self-adhesive resin cements favored the increase in longevity and the clinical performance of indirect aesthetic restorations. Case Report: Patient J.B.S, 57 years old, male, complained of edentulous spaces and unpleasant aesthetics in the lower jaw arch. During the anamnesis, deficiency in composite resin restorations in terms of texture and color, and occlusal trauma in the dental element 33 were evaluated. To plan the case, the patient was subjected to a molding with addition silicone, where the material was directed to laboratory for study, being able to define that the entire infrastructure of the implants would be in zirconia. Treatment was performed with 8 crowns on teeth by a system of lithium disilicate, IPSemax on elements 34 to 43 and 45, through wear of the dental elements followed by the insertion of the crowns, and 4 crowns on implantation on elements 35,36,44 and 46 using a zirconia-based system. Implant surgery was performed on these dental elements, with immediate placement of the crowns in lithium disilicate. Final Considerations: The use of lithium disilicate ceramics enabled the functional and aesthetic recovery of the smile when conventional laminated veneer preparations were used, as well as the detailed study based on the addition of silicone molding guided the study towards the correct installation. ceramic implants and crowns.Introduction: The constant search for a harmonic and aesthetic smile raises the level of demand and expectation of patients. The laminated veneers stand out as a treatment option for aesthetic rehabilitation in clinical practice as they provide more conservative procedures and mimic dental structures. The development of new ceramic systems reinforced by lithium disilicate and self-adhesive resin cements favored the increase in longevity and the clinical performance of indirect aesthetic restorations. Case Report: Patient J.B.S, 57 years old, male, complained of edentulous spaces and unpleasant aesthetics in the lower jaw arch. During the anamnesis, deficiency in composite resin restorations in terms of texture and color, and occlusal trauma in the dental element 33 were evaluated. To plan the case, the patient was subjected to a molding with addition silicone, where the material was directed to laboratory for study, being able to define that the entire infrastructure of the implants would be in zirconia. Treatment was performed with 8 crowns on teeth by a system of lithium disilicate, IPSemax on elements 34 to 43 and 45, through wear of the dental elements followed by the insertion of the crowns, and 4 crowns on implantation on elements 35,36,44 and 46 using a zirconia-based system. Implant surgery was performed on these dental elements, with immediate placement of the crowns in lithium disilicate. Final Considerations: The use of lithium disilicate ceramics enabled the functional and aesthetic recovery of the smile when conventional laminated veneer preparations were used, as well as the detailed study based on the addition of silicone molding guided the study towards the correct installation. ceramic implants and crowns

Extraction of high-quality DNA from ethanol-preserved tropical plant tissues

BACKGROUND: Proper conservation of plant samples, especially during remote field collection, is essential to assure quality of extracted DNA. Tropical plant species contain considerable amounts of secondary compounds, such as polysaccharides, phenols, and latex, which affect DNA quality during extraction. The suitability of ethanol (96% v/v) as a preservative solution prior to DNA extraction was evaluated using leaves of Jatropha curcas and other tropical species. RESULTS: Total DNA extracted from leaf samples stored in liquid nitrogen or ethanol from J. curcas and other tropical species (Theobroma cacao, Coffea arabica, Ricinus communis, Saccharum spp., and Solanum lycopersicon) was similar in quality, with high-molecular-weight DNA visualized by gel electrophoresis. DNA quality was confirmed by digestion with EcoRI or HindIII and by amplification of the ribosomal gene internal transcribed spacer region. Leaf tissue of J. curcas was analyzed by light and transmission electron microscopy before and after exposure to ethanol. Our results indicate that leaf samples can be successfully preserved in ethanol for long periods (30 days) as a viable method for fixation and conservation of DNA from leaves. The success of this technique is likely due to reduction or inactivation of secondary metabolites that could contaminate or degrade genomic DNA. CONCLUSIONS: Tissue conservation in 96% ethanol represents an attractive low-cost alternative to commonly used methods for preservation of samples for DNA extraction. This technique yields DNA of equivalent quality to that obtained from fresh or frozen tissue

Localização das reservas cotiledonares de Theobroma grandiflorum (Willd. ex Spreng.) K. Schum., T. subincanum Mart., T. bicolor Bonpl. e analogias com T. cacao L.

Cotyledon mesophyll cell morphology and lipid and protein synthesis of T. grandiflorum, T. subincanum and T. bicolor were analyzed and compared with T. cacao. These species possess foliar cotyledons folded around the hypocotyl radicle axis, typical of Sterculiaceae. Fruit size, morphology and weight are very distinct amongst the four species and so are the respective seeds. The main axis of the T. grandiflorum and T. bicolor seeds measured about 30 mm, while T. subincanum and T. cacao seeds measured 17 mm and 26 mm respectively. The seed weights of T. grandiflorum, T. bicolor, T. subincanum and T. cacao were 11.6 g, 9.4 g, 2.1 g and 3.0 g, respectively. The cotyledon mesophylls of the four species contained mainly polysaccharides and lipid-protein reserve cells. Theobroma cacao, T. grandiflorum and T. subincanum were composed of greater than 50% lipids. For the four species, lipid globules gradually accumulated adjacent to the cell wall, and these globules measured from 1 to 3 µm. TEM showed low-density proteins inside the central vacuole of the young mesophyll cells of T. cacao. The protein reserves of the mature cells were densely scattered amongst the lipid bodies, and a few starch granules occurred together with the cotyledon mesophyll of the four species. Polyphenolic cells were found throughout the mesophyll cells or aligned with the respective vascular bundles. Immature cells demonstrated the capacity to synthesize all these reserves, but gradually the pre-determined cells produced mainly lipid-protein reserves. Besides the unique characteristics of the T. cacao products, the lipid-protein synthesis capacities of T. grandiflorum, T. subincanum and T. bicolor suggest various possibilities for new industrialized food, pharmaceutical and cosmetic products.As células do mesofilo cotiledonar e respectivas sínteses lípide-protéicas de Theobroma grandiflorum, T. subincanum e T. bicolor são analisadas e comparadas ao T. cacao. As espécies mencionadas possuem os cotilédones foliáceos e redobrados em torno do eixo hipocótilo-radicular, típicos de Sterculiaceae; o tamanho dos frutos e também a morfologia, o peso e as respectivas sementes são distintos entre as quatro espécies. As sementes de T. grandiflorum e T. bicolor medem 30 mm no eixo principal, enquanto em T. subincanum e T. cacao medem 17 mm e 6 mm, respectivamente e nesta mesma ordem pesam 11,6 g, 9,4 g, 2,1 g e 3,0 g. Os mesofilos cotiledonares contêm células com reservas polissacárides e lípide-proteicas. Theobroma cacao, T. grandiflorum e T. subincanum contêm acima de 50% de lipídeos. Nas quatro espécies, os glóbulos lipídicos acumulam-se gradualmente, adjacentes à parede celular e medem entre 1 a 3 µm. A microscopia eletrônica de transmissão mostrou a precipitação pouco densa das proteínas no vacúolo central das células jovens do mesofilo de T. cacao. Nas células maduras, a proteína de reserva está densamente entremeada por glóbulos lipídicos; poucos grãos de amido ocorrem no mesofilo cotiledonar destas quatro espécies. As células polifenólicas estão dispersas no mesofilo cotiledonar ou alinhadas próximas ao feixe vascular. As células imaturas demonstraram capacidade de síntese de todas as reservas, mas gradualmente as células predeterminadas, produzem principalmente reservas lípide-proteicas. Não obstante a característica única dos reconhecidos produtos de T. cacao, a capacidade de síntese lípide-proteica do T. grandiflorum, T. subincanum e T. bicolor sugerem novas possibilidades para a indústria de alimentos, produtos farmacêuticos e cosméticos

Localização das reservas cotiledonares de Theobroma grandiflorum (Willd. ex Spreng.) K. Schum., T. subincanum Mart., T. bicolor Bonpl. e analogias com T. cacao L.

Cotyledon mesophyll cell morphology and lipid and protein synthesis of T. grandiflorum, T. subincanum and T. bicolor were analyzed and compared with T. cacao. These species possess foliar cotyledons folded around the hypocotyl radicle axis, typical of Sterculiaceae. Fruit size, morphology and weight are very distinct amongst the four species and so are the respective seeds. The main axis of the T. grandiflorum and T. bicolor seeds measured about 30 mm, while T. subincanum and T. cacao seeds measured 17 mm and 26 mm respectively. The seed weights of T. grandiflorum, T. bicolor, T. subincanum and T. cacao were 11.6 g, 9.4 g, 2.1 g and 3.0 g, respectively. The cotyledon mesophylls of the four species contained mainly polysaccharides and lipid-protein reserve cells. Theobroma cacao, T. grandiflorum and T. subincanum were composed of greater than 50% lipids. For the four species, lipid globules gradually accumulated adjacent to the cell wall, and these globules measured from 1 to 3 µm. TEM showed low-density proteins inside the central vacuole of the young mesophyll cells of T. cacao. The protein reserves of the mature cells were densely scattered amongst the lipid bodies, and a few starch granules occurred together with the cotyledon mesophyll of the four species. Polyphenolic cells were found throughout the mesophyll cells or aligned with the respective vascular bundles. Immature cells demonstrated the capacity to synthesize all these reserves, but gradually the pre-determined cells produced mainly lipid-protein reserves. Besides the unique characteristics of the T. cacao products, the lipid-protein synthesis capacities of T. grandiflorum, T. subincanum and T. bicolor suggest various possibilities for new industrialized food, pharmaceutical and cosmetic products.As células do mesofilo cotiledonar e respectivas sínteses lípide-protéicas de Theobroma grandiflorum, T. subincanum e T. bicolor são analisadas e comparadas ao T. cacao. As espécies mencionadas possuem os cotilédones foliáceos e redobrados em torno do eixo hipocótilo-radicular, típicos de Sterculiaceae; o tamanho dos frutos e também a morfologia, o peso e as respectivas sementes são distintos entre as quatro espécies. As sementes de T. grandiflorum e T. bicolor medem 30 mm no eixo principal, enquanto em T. subincanum e T. cacao medem 17 mm e 6 mm, respectivamente e nesta mesma ordem pesam 11,6 g, 9,4 g, 2,1 g e 3,0 g. Os mesofilos cotiledonares contêm células com reservas polissacárides e lípide-proteicas. Theobroma cacao, T. grandiflorum e T. subincanum contêm acima de 50% de lipídeos. Nas quatro espécies, os glóbulos lipídicos acumulam-se gradualmente, adjacentes à parede celular e medem entre 1 a 3 µm. A microscopia eletrônica de transmissão mostrou a precipitação pouco densa das proteínas no vacúolo central das células jovens do mesofilo de T. cacao. Nas células maduras, a proteína de reserva está densamente entremeada por glóbulos lipídicos; poucos grãos de amido ocorrem no mesofilo cotiledonar destas quatro espécies. As células polifenólicas estão dispersas no mesofilo cotiledonar ou alinhadas próximas ao feixe vascular. As células imaturas demonstraram capacidade de síntese de todas as reservas, mas gradualmente as células predeterminadas, produzem principalmente reservas lípide-proteicas. Não obstante a característica única dos reconhecidos produtos de T. cacao, a capacidade de síntese lípide-proteica do T. grandiflorum, T. subincanum e T. bicolor sugerem novas possibilidades para a indústria de alimentos, produtos farmacêuticos e cosméticos.31114715

Localização das reservas cotiledonares de theobroma grandiflorum (willd. ex spreng.) k. schum., t. subincanum mart., t. bicolor bonpl. e analogias com t. cacao l.

Cotyledon mesophyll cell morphology and lipid and protein synthesis of T. grandiflorum, T. subincanum and T. bicolor were analyzed and compared with T. cacao. These species possess foliar cotyledons folded around the hypocotyl radicle axis, typical of Sterculiaceae. Fruit size, morphology and weight are very distinct amongst the four species and so are the respective seeds. The main axis of the T. grandiflorum and T. bicolor seeds measured about 30 mm, while T. subincanum and T. cacao seeds measured 17 mm and 26 mm respectively. The seed weights of T. grandiflorum, T. bicolor, T. subincanum and T. cacao were 11.6 g, 9.4 g, 2.1 g and 3.0 g, respectively. The cotyledon mesophylls of the four species contained mainly polysaccharides and lipid-protein reserve cells. Theobroma cacao, T. grandiflorum and T. subincanum were composed of greater than 50% lipids. For the four species, lipid globules gradually accumulated adjacent to the cell wall, and these globules measured from 1 to 3 µm. TEM showed low-density proteins inside the central vacuole of the young mesophyll cells of T. cacao. The protein reserves of the mature cells were densely scattered amongst the lipid bodies, and a few starch granules occurred together with the cotyledon mesophyll of the four species. Polyphenolic cells were found throughout the mesophyll cells or aligned with the respective vascular bundles. Immature cells demonstrated the capacity to synthesize all these reserves, but gradually the pre-determined cells produced mainly lipid-protein reserves. Besides the unique characteristics of the T. cacao products, the lipid-protein synthesis capacities of T. grandiflorum, T. subincanum and T. bicolor suggest various possibilities for new industrialized food, pharmaceutical and cosmetic products311147154As células do mesofilo cotiledonar e respectivas sínteses lípide-protéicas de Theobroma grandiflorum, T. subincanum e T. bicolor são analisadas e comparadas ao T. cacao. As espécies mencionadas possuem os cotilédones foliáceos e redobrados em torno do eixo hipocótilo-radicular, típicos de Sterculiaceae; o tamanho dos frutos e também a morfologia, o peso e as respectivas sementes são distintos entre as quatro espécies. As sementes de T. grandiflorum e T. bicolor medem 30 mm no eixo principal, enquanto em T. subincanum e T. cacao medem 17 mm e 6 mm, respectivamente e nesta mesma ordem pesam 11,6 g, 9,4 g, 2,1 g e 3,0 g. Os mesofilos cotiledonares contêm células com reservas polissacárides e lípide-proteicas. Theobroma cacao, T. grandiflorum e T. subincanum contêm acima de 50% de lipídeos. Nas quatro espécies, os glóbulos lipídicos acumulam-se gradualmente, adjacentes à parede celular e medem entre 1 a 3 µm. A microscopia eletrônica de transmissão mostrou a precipitação pouco densa das proteínas no vacúolo central das células jovens do mesofilo de T. cacao. Nas células maduras, a proteína de reserva está densamente entremeada por glóbulos lipídicos; poucos grãos de amido ocorrem no mesofilo cotiledonar destas quatro espécies. As células polifenólicas estão dispersas no mesofilo cotiledonar ou alinhadas próximas ao feixe vascular. As células imaturas demonstraram capacidade de síntese de todas as reservas, mas gradualmente as células predeterminadas, produzem principalmente reservas lípide-proteicas. Não obstante a característica única dos reconhecidos produtos de T. cacao, a capacidade de síntese lípide-proteica do T. grandiflorum, T. subincanum e T. bicolor sugerem novas possibilidades para a indústria de alimentos, produtos farmacêuticos e cosmético

As células polifenólicas e as suas inter-relações com as células cotiledonares em sete espécies de Theobroma (Sterculiaceae)

The amount of cotyledon polyphenolic cells varies extensively within the Theobroma species. The polyphenolic compounds of these cells play a protective role and furthermore have an important function in the development of chocolate flavour. The morphology of the polyphenolic cells of the mesophyll is described and the development of these idioblasts in Theobroma cacao L., T. subincanum Mart., T. obovatum Klotzsch ex Bernoulli, T. grandiflorum (Willd. ex Spreng.) K. Schum., T. microcarpum Mart., T. bicolor Bonpl. and T. speciosum Willd. ex Spreng analysed. The total polyphenolic content in the seeds as determined by spectrophotometry showed a variation of about forty times. The alive, transparent polyphenolic cells are scattered throughout the cotiledonary mesophyll. However the polyphenolic cells of T. cacao and T. grandiflorum are also aligned perpendicularly with respect to the mesophyll borders and, in addition, both species display polyphenolic cells with a natural translucent purple colour. All the species analysed contained polyphenolic cells scattered throughout the parenchymal cells and also in a lengthwise association with vascular bundles. In T. bicolor and T. speciosum, the species with the lowest polyphenolic contents, these cells were mostly located around the vascular bundles. Using Scanning Electron Microscopy, the polyphenolic cells demonstrated a complex cytoarchitecture, and after fixing with glutaraldhyde, the polyphenolic secretion was shown to remain as a single unit or was organized into round droplets. Transmission Electron Microscopy displayed immature plastids from young mesophyll cells containing eletron-dense deposits similar to phenolic substances, suggesting that Theobroma plastids are involved in the synthesis of phenolics.A quantidade de células polifenólicas dos cotilédones das espécies de Theobroma variam extensivamente. Os compostos polifenólicos destas células além da função de proteção participam no desenvolvimento do aroma do chocolate. A morfologia das células polifenólicas do mesofilo é descrita e também é analisado o desenvolvimento dos idioblastos em T. cacao L., T. subincanum Mart., T. obovatum Klotzsch ex Bernoulli, T. grandiflorum (Willd. ex Spreng.) K. Schum., T. microcarpum Mart., T. bicolor Bonpl. e T. speciosum Willd. ex Spreng. A quantidade de polifenóis totais determinada por espectrofotometria apresentou uma grande variação, cerca de 40 vezes entre T. cacao (variedade forastero). As células polifenólicas apresentam-se transparentes e dispersas pelo mesofilo cotiledonar. Em T. cacao e T. grandiflorum grande número de células estão alinhadas perpendicularmente à borda do mesofilo e apresentam coloração púrpura translúcida. Entretanto, em todas as espécies as células polifenólicas também associam-se ao feixe vascular. Nas espécies T. bicolor e T. speciosum, com baixo conteúdo polifenólico, estão localizadas apenas na região do feixe vascular. À microscopia eletrônica de varredura, as células polifenólicas apresentam uma complexa citoarquitetura e após a fixação em glutaraldeído, a secreção polifenólica exibe um só conteúdo ou fragmenta-se em várias gotas esféricas. À microscopia eletrônica de transmissão aparecem nas células jovens do mesofilo, plastídeos imaturos eletrondensos, semelhantes a substâncias polifenólicas sugerindo que em Theobroma os plastídeos estão envolvidos na síntese de polifenóis