22 resultados para Pragas

em Universidade Federal do Rio Grande do Norte(UFRN)


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present research deals with the modernization process of the Cidade da Parahyba2, between 1850 and 1924, and its relation with the cotton economy, which represented the main source of wealth accumulation for both the private and the public sectors throughout the First Republic. This study on urban history was developed by focusing on the understanding of the city s spatial formation, and despite its emphasis on the economic aspects involved, other factors that also contribute to the development of the social life were not put aside. The modernization process of the Cidade da Parahyba was also analyzed during the period established for the study according to a chronological and thematic approach that established comparisons with the financial situation of the State, whenever this was necessary, with special attention to the contribution of the cotton economy to the State´s revenues. It was possible to detect a lack of financial help and loans from the federal and municipal administrations for finishing several public works already underway in the capital, since the federal funds allocated to the State of Parahyba do Norte were rather employed in emergency works against droughts and in agricultural development. One can then conclude that the financial resources required for the urban interventions were withdrawn from the State s treasury itself, resources that were collected mainly from activities such as cotton exportation and cotton trading. Another factor shows the interdependence between the urban remodeling and the cotton economy: during the years marked by great droughts or by hard plagues on the cotton plantations, cotton production decreased, as well as the State s finances. The first measures taken by the State s administrators were to halt all projects of urban remodeling in progress in the Cidade da Parahyba, which was, clearly, the most privileged city by the State s presidents during the period analyzed. 2 The city of João Pessoa was named Cidade da Parahyba, a designation that remained until September 1930, when it received its present-day name in order to pay homage to the president of the State, João Pessoa Cavalcanti de Albuquerque, murdered in the city of Recife in August of that same year. At that time, the State of Paraíba was known as Parahyba do Norte. Since this work is limited to a period of time comprised within the First Republic, the names employed respect the terms used in those days

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Methomyl (Lannate®) is an insecticide from the carbamate group, frequently used in pest control in various types of crops. This compound works inhibiting the activity of the enzyme acetylcholinesterase. The use of physicochemical and ecotoxicological analysis is the most efficient strategy for the correct characterization and control of residues of metomil. The main objectives of this study were to evaluate the acute toxicity of methomyl in 96 hours of exposure and, through a sublethal assay of 5 hours, to assess its effect on the activity of acetylcholinesterase present in brain and squeletic dorsal muscle of the Danio rerio fish. The results showed that the LC50-96 found to D. rerio was 3.4 mg/L and it was found through the average of four definitive tests. In vitro assays were used to test the inhibitory action of methomyl directly over soluble AChE, extracted from the squeletic dorsal muscle, with maximum inhibition of 68.57% to the insecticide concentrations of 0.2 mg/L. In sublethal tests with D. rerio, inhibitory effect of methomyl was found over the soluble form of AChE in the squeletic dorsal muscle, both in one and five hours of fish exposure to the insecticide. In both period, the average values of inhibition were around 61%. In the same condition, no significant inhibitory effect of methomyl soluble and membrane AChE of the D. rerio was observed in the 0.42, 0.85, 1.70 and 2.50 mg/L concentrations and in both times of fish exposure

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Serines proteinases inhibitors (PIs) are widely distributed in nature and are able to inhibit both in vitro and in vivo enzymatic activites. Seed PIs in than leguminous are classified in seven families, Bowman-Birk and Kunitz type families that most studied representing an important role in the first line of defense toward insects pests. Some Kunitz type inhibitors possess activities serine and cysteine for proteinases named bifunctional inhibitor, as ApTKI the inhibitor isolate from seed of Adenanthera pavonina. The A. pavonina inhibitor presenting the uncommon property and was used for interaction studies between proteinases serine (trypsin) and cysteine (papain). In order to determinate the in vitro interaction of ApTKI against enzymes inhibitor purification was carried cut by using chromatographic techniques and inhibition assays. The 3D model of the bifunctional inhibitor ApTKI was constructed SWISS-MODEL program by homology modeling using soybean trypsin inhibitor (STI, pdb:1ba7), as template which presented 40% of identity to A. pavonina inhibitor. Model quality was evaluated by PROCHECK program. Moreover in silico analyzes of formed complex between the enzymes and ApTKI was evaluated by HEX 4.5 program. In vitro results confirmed the inhibitory assays, where the inhibitor presented the ability to simultaneously inhibit trypsin and papain. The residues encountered in the inhibitor model of folder structural three-dimensional that make contact to enzymes target coud explain the specificity pattern against serine and cysteine proteinases

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The fruit fly Ceratitis capitata is considered the most destructive pest of the world fruitculture. Many pest management practices, mainly based on agrochemicals, have been developed to allow the world-wide commerce of fruit. Solutions to decrease the use of synthetic insecticides in agriculture are based on the development of new target-specific compounds which cause less damage to the environment, especially vegetal proteins with insecticidal effects. The aim of this work was to evaluate the deleterious effect of a purified vicilin of E. velutina (EvV) seeds to C. capitata larvae and adult insects and to investigate the mechanisms involved in these effects. EvV was purified, characterized and its deleterious effect was tested in bioassay systems. EvV mechanism of action was determined by immunodetection techniques and fluorescence localization in chitin structures that are present in C. capitata digestory system. EvV is a glycoprotein with affinity to chitin. Its molecular weight, of 216,57 kDa, was determined by gel filtration chromatography in FPLC system. Using SDS-PAGE, it was possible to observe EvV dissociation in two main subunits of 54,8 and 50,8 kDa. When it was submitted to eletrophoresis in native conditions, EvV presented only one band of acid characteristic. The WD50 and LD50 values found in the bioassays were 0,13% and 0,14% (w/w), respectively for the larvae. EvV deleterious effects were related to the binding to chitin structures presented in peritrophic membrane and gut epithelial cells, associated with its low digestibility in C. capitata digestive tract. The results described herein are the first demonstration of the larvicidal effects of plant protein on C. capitata larvae. EvV may be part of the pest management programs, in the toxic bait composition, or an alternative in plant improvement program

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Chitin is an important structural component of the cellular wall of fungi and exoskeleton of many invertebrate plagues, such as insects and nematodes. In digestory systems of insects it forms a named matrix of peritrophic membrane. One of the most studied interaction models protein-carbohydrate is the model that involves chitin-binding proteins. Among the involved characterized domains already in this interaction if they detach the hevein domain (HD), from of Hevea brasiliensis (Rubber tree), the R&R consensus domain (R&R), found in cuticular proteins of insects, and the motif called in this study as conglicinin motif (CD), found in the cristallography structure of the β-conglicinin bounded with GlcNac. These three chitin-binding domains had been used to determine which of them could be involved in silico in the interaction of Canavalia ensiformis and Vigna unguiculata vicilins with chitin, as well as associate these results with the WD50 of these vicilins for Callosobruchus maculatus larvae. The technique of comparative modeling was used for construction of the model 3D of the vicilin of V. unguiculata, that was not found in the data bases. Using the ClustalW program it was gotten localization of these domains in the vicilins primary structure. The domains R&R and CD had been found with bigger homology in the vicilins primary sequences and had been target of interaction studies. Through program GRAMM models of interaction ( dockings ) of the vicilins with GlcNac had been gotten. The results had shown that, through analysis in silico, HD is not part of the vicilins structures, proving the result gotten with the alignment of the primary sequences; the R&R domain, although not to have structural similarity in the vicilins, probably it has a participation in the activity of interaction of these with GlcNac; whereas the CD domain participates directly in the interaction of the vicilins with GlcNac. These results in silico show that the amino acid number, the types and the amount of binding made for the CD motif with GlcNac seem to be directly associates to the deleterious power that these vicilins show for C. maculatus larvae. This can give an initial step in the briefing of as the vicilins interact with alive chitin in and exert its toxic power for insects that possess peritrophic membrane

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Chitin-binding vicilins from legume seeds (Erythrina velutina. Canavalia ensiformes and Phaseolus vulgares) were isolated by ammonium sulfate followed by affinity chromatography on a chitin column. Effect of these vicilins on female adults of Ceratitis capitata was examined by bioassay and in a semi-field assay model. Mechanism of action of the vicilins was determined by in vivo digestibility and chitin affinity. Among the tested vicilins, E. velutina when added to diet caused strong effect on mortality at 10% dose. This insecticidal property was tested in a semi-field assay which showed the same effect observed in laboratory conditions, where doses of 10% and 15% were lethal to female adults of C. capitata. These deleterious effects were not only associated to the binding to chitin structures present in peritrophic membrane, but principally to its low digestibility in the C. capitata digestive tract. This fact was confirmed because chiting binding proteins as WGA and the other tested vicilins were not toxic to female adults of C. capitata due susceptibility of these proteins to digestive enzymes of the insects. By other side EvV was more resistant to digestive enzymes, causing deleterious effects on female adults of C. capitata. These results showed that EvV may be part of the pest management programs or an alternative in plant improvement program in the population control of this fruticulture pest

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Grains and legume seeds are foods that form the basis of the diets of many cultures around the world, winch contritbute to the daily nutrient requirements of humans. Vicilins (7S globulin) are storage proteins found in legume seeds, and may have an additional function constitutive defense of the embryo against pests and pathogens. In this work the vicilin from Anadenanthera macrocarpa - AmV (red-angico), was purified and partially characterized, its effect on development and larval survival and adult emergence of Callosobruchus maculatus was evaluated by determination of LD50, WD50 and ED50 in system bioassay. Purification of vicilin was initiated by the chitin affinity chromatography and then gel filtration (Superdex 75 Tricorn 10x300 mm) FPLC system followed by reverse phase chromatography (C8 phenomenex) on HPLC system. Bioassays WD50 and LD50 for larvae were 0.32% and 0.33% (w:w) respectively, since the ED50 for adults was 0.096%. The probable mechanism of action was evaluated by testing digestibility of AmV in vitro, and observed for the involvement of two fragments vicilins immunoreactive against polyclonal Anti-vicilin from Erythrina velutina (Anti-EvV) about of 22 and 13 kDa chitin binding. The AmV in its native form has been recognized by the anti-EvV, indicating that there is a conserved region in the vicilin and is probably corresponding to the chitin binding domains. These results point to a new vicilin chitin binding that can subsequently be used as a possible biopesticide protein source, in order to control insect pest C. maculatus and confirm literature findings that demonstrate vicilin in the presence of different kinds of ligands to conserved regions chitin not yet characterized

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Among the pests that attack corn crop in Brazil, there is Spodoptera frugiperda (JE Smith, 1797) (Lepidoptera: Noctuidae), known as fall armyworm, which is the major corn pest. Due to genetic instability during serial passage of baculoviruses in insect cell culture, the viral bioinseticides in vitro production development is the greatest challenge for mass production of this bioproduct. Successive passages of virus using extracellular viruses (BVs), necessary during viral bioinseticides production scaling up, leads to the appearance of aberrant forms of virus, a process so called as "passage effect ". The main consequence of passage effect is the production of occlusion bodies (OB) decrease, preventing its production using in vitro process. In this study, it was carried out a serial passage of baculovirus Spodoptera frugiperda multiple nucleopolyhedrovirus, isolate 18, using Sf21 cells. A decrease in the production of occlusion bodies from 170 to 92 in the third to fourth passage was observed. A factorial experimental design (22) was employed to verify the influence of two input variables, concentration of the hormone 20 - hydroxyecdysone (CH) and cholesterol (CC) on the values of response variables (volumetric and the specific OB production) of the process, seeking to define the optimum operating ranges trying to reverse or minimize the passage effect. The result indicated a negative influence of the cholesterol addition and positive effect in the hormone supplementation which the optimum range found for the concentrations studied were 8 to 10μg/mL and 5 to 6.5 mg / mL, for cholesterol and hormone concentrations respectively. New experiments were performed with addition of hormone and cholesterol in order to check the influence of these additives on the OB production independently. While the best result obtained from the factorial experiment was 9.4 x 107 OB/mL and 128.4 specific OB/cell, with the addition of only 6μg/mL 20-hydroxyecdysone these concentrations increased to 1.9 x 108 OB/mL and 182.9 OB/cell for volumetric and specific OB production, respectively. This result confirms that the addition of the hormone 20-hydroxyecdysone enhances the SfMNPV in vitro production process performance using Sf21 cells

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hybrids among transgenic plants and related species are expected to occur if they are sympatric and when there are not crossing barriers; as is the case, in Brazil, of cry1Ac transgenic cotton and Gossypium barbadense. This species has been maintained as dooryard plants, and should be preserved as a genetic resource. Hybrids were evaluated about traits related to fitness, leading to infer about its chances of survivor and selection. A barbadense genotype collected at the state of Mato Grosso was outcrossed to the variety DP 404, containing the gene cry1Ac, and to the isoline DP 404. All the F1 individuals and 122 among 170 F2 individuals expressed the toxin, and presented levels of resistance to pink bollworm (Pectinophora gossypiella) and cotton leafworm (Alabama argillacea) equivalent to the transgenic parent and superior to the isoline, barbadense or non transgenic hybrids. The percentage of germination and number of days to germinate did not differ among genotypes. Anthesis of the first flower and opening of the first cotton boll occurred earlier for herbaceous cotton and F1 hybrids than F2 population in average; all the populations presented a number of days to flower and opening of the first boll smaller then barbadense. The highest plants were barbadenses, and herbaceus the smallest, with F1 and F2 populations presenting intermediary heights. The number of seeds per plants were superior for F1 hybrids an herbaceous cotton, F2 populations were in average intermediary; the barbadense genotype produced the smallest number of seeds per plant. Pink bollworm, mainly, and also cotton leafworm, are important barbadense pests, so the transgene positive effect could favor the selection of hybrids, and hence G. hirsutum genome, against the maintenance of pure G. barbadense genome. The selection may be influenced by the plant uses: the smaller size of hybrids when compared to the barbadense may lead them to be differentiated from these parents to which medicinal properties are attributed; on the other hand, the greater boll production may favor hybrids maintenance with the purpose of producing lamp wicks, or use as an ornamental or swab

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The cats (Felis catus) were domesticated about 9,500 years ago due to the advent of agriculture, being used to control the pests that devastated the food harvested. These animals went through an artificial selection and over generations and millennia had their behavior and morphology changed by humans. This process of domestication by man gave rise to a special ability, the understanding of human pointing gestures, clearly noticed while we feed our pets. Our goal in this study was to assess the comprehension of pointing gestures by cats and also verify the influence that social interactions exerts on the development of this ability. We found that experimental subjects from both groups, solitary animals and social animals, were able to follow human indication in order to find hidden food. However, social interaction had no effect on cats performances. The ability tested here probably evolved during the process of domestication of this species, and social interaction seems to exert little or no influence upon its expression

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Soil contamination by pesticides is an environmental problem that needs to be monitored and avoided. However, the lack of fast, accurate and low cost analytical methods for discovering residual pesticide in complex matrices, such as soil, is a problem still unresolved. This problem needs to be solved before we are able to assess the quality of environmental samples. The intensive use of pesticides has increased since the 60s, because the dependence of their use, causing biological imbalances and promoting resistance and recurrence of high populations of pests and pathogens (upwelling). This has contributed to the appearance of new pests that were previously under natural control. To develop analytical methods that are able to quantify residues pesticide in complex environment. It is still a challenge for many laboratories. The integration of two analytical methods one ecotoxicological and another chemical demonstrates the potential for environmental analysis of methamidophos. The aim of this study was to evaluate an ecotoxicological method as "screening" analytical methamidophos in the soil and perform analytical confirmation in the samples of the concentration of the analyte by chemical method LC-MS/MS In this work we tested two soils: a clayey and sandy, both in contact with the kinetic methamidophos model followed pseudo-second order. The clay soil showed higher absorption of methamidophos and followed the Freundlich model, while the sandy, the Langmuir model. The chemical method was validated LC-MS/MS satisfactory, showing all parameters of linearity, range, precision, accuracy, and sensitivity adequate. In chronic ecotoxicological tests with C. dubia, the NOEC was 4.93 and 3.24 for ng L-1 of methamidophos to elutriate assays of sandy and clay soils, respectively. The method for ecotoxicological levels was more sensitive than LC-MS/MS detection of methamidophos, loamy and sandy soils. However, decreasing the concentration of the standard for analytical methamidophos and adjusting for the validation conditions chemical acquires a limit of quantification (LOQ) in ng L-1, consistent with the provisions of ecotoxicological test. The methods described should be used as an analytical tool for methamidophos in soil, and the ecotoxicological analysis can be used as a "screening" and LC-MS/MS as confirmatory analysis of the analyte molecule, confirming the objectives of this work

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Societal concerns about environmental sustainability has lead to the development of ecologically-friendly alternatives to chemical insecticides for crop protection. One such alternative is biological pest control. In particular, baculoviruses are well suited as insect biopesticides due to their narrow host specificity and relative ease of propagation. In Brazil, the baculovirus Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV) is the main biological control agent employed for the soybean pest, Anticarsia gemmatalis. This baculovirus biopesticide is currently produced using caterpillars, but increasing market demand for the product has encouraged the development of an in vitro manufacturing process, which can be scaled up to much higher virus productivities. In this study, three wild-type AgMNPV isolates (AgMNPV-2D, AgMNPV-MP2 and AgMNPV-MP5) and a recombinant form (vAgEGT-LacZ) were characterised in terms of occlusion body (OB) production and infection kinetics, to enable future optimisation of the in vitro production process. These viruses were propagated using a Spodoptera frugiperda (IPLB-SF21) insect cell line grown in shaker-flask batch cultures. Among the virus isolates tested, AgMNPV-MP5 was found to be the best producer, yielding (5.3±0.85)x108 OB/mL after 8 days post infection. The characterisation of vAgEGT-LacZ propagation in suspension cell cultures has not been previously reported in the literature; hence it became the main focus for this thesis. In particular, it was carried out a study on the effect of the multiplicity of infection (MOI) on OB production. Five successive batches were performed getting a final production (8.9±1.42)x1014 occlusion bodies, considering that production is related for a bioreactor with final volume of 10m3. A low MOI associated with a fed-batch process for vAgEGT-LacZ production was found to support a 3-fold higher OB yield when compared to the default batch process (1.8x107 and 5.3x107 OB/mL, respectively). This yield is competitive with regards to the production process.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The exceeded use of the natural resources required by the modern agriculture has been caused soil impoverishment, soil salinization and soil compaction. The unreasonable use of chemical fertilizers and pesticides causes chemical imbalances in the plant tissues, nutritional losses, taste chances and human health problems. The monocrops are more vulnerable to the pest and disease attacks. The aim of this work were to indicate the better relative planting time of the cowpea bean for the sesame/cowpea bean intercropping based on the evaluation of agronomic, economic, ecological and physiological parameters and to evaluate the viability of the cow urine and cassava wastewater use as alternative fertilizers on the sesame cultivation. In a field essay, when the sesame/cowpea bean was evaluate, the mainly treatments were the single planting of the two cultures and the multiple cropping, with the cowpea bean being planted on the same time, 7, 14 and 21 days after the sesame. The mainly treatments of the second essay were the combined doses of the cow urine (0 and 50 ml) and cassava wastewater (0, 500 and 1000 mL). In the intercrop evaluation significant differences were found between the treatments for the most of the parameters. It was verified that as the sowing of the cowpea bean was retarded in relation to the sesame sowing, the sesame performance increased when the cowpea bean performance decreased. The treatment 7 days balanced the competition relations that occurred between the two crops in the intercrop. The sesame presented little pronounced responses to the different doses of cassava wastewater. The cow urine affected the sesame growth and the growth rates increased with the increasing of the application of the product. The responses of the sesame growth to the cow urine application must be related both the nutritional richness of the product and the presence of growth stimulating substances. The obtained results indicated that in the sesame/cowpea bean intercropping, when the sesame is planted 7 days after the sesame, there is a higher possibility of the net gains to the farmer. Cow urine and cassava wastewater may be used as additional organic fertilizers

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The currently main development model on global society is driven by an economic rationality that endangers the environment and social justice. More and more, attention to this way of production and consumption is increasing, boosting research for sustainable development, with an environmental rationality that can harmonize nature preservation and welfare of all socioeconomic classes. One of the efforts on this sense is changing the sources supplying the energy demand, replacing fossil fuels for renewable and cleaner sources, such as biofuels. Carthamus tinctorius (safflower) is an oilseed crop with potential for biodiesel production, with good oil yield and chemical profile, allied to good adaptation to climates such like the northeastern semiarid lands of Brazil. With public policies fomentation, the use of this species may be an interesting alternative for family farming. In farming in general, the use of pesticides to prevent and combat diseases and plagues is common, which is not a sustainable practice. Thus, there are researched alternative, less dangerous substances. In this study, it was aimed to assess if neem (Azadirachta indica) leaf extract (20% m/v) and Bordeaux mixture (copper sulfate) have effects on safflower. It was also aimed to verify acceptance of farmers on safflower crop in Apodi, a municipality in Rio Grande do Norte state, Brazil, in view of it being localized in the aimed region for this crop cultivation. Besides that, understanding that the farmers’ knowledge and inclination to adopt the crop is fundamental for the introduction of this species and socioeconomic growth due to its exploration. In addition, a booklet with basic information on safflower was produced. In the field experiment, the fungicides were pulverized on plants cultivated in field experimental plots, with collection of leaf samples for analysis on anatomy, cuticle, and epicuticular wax morphology, the protective layer that interfaces with the surrounding ambient. In Apodi, forty-five farmers from Potiguar Cooperative of Apiculture and Sustainable Rural Development (COOPAPI) underwent semi-structured interviews, which also addressed their assessment on currently cultivated crops and perception of pesticide uses and sustainable alternatives. After comparing using analysis of variance, it was found that there was no difference between treatments in the experiment, as well as no anatomical or morphological modifications. Safflower acceptation among farmers was wide, with 84% of interviewees believing in a perspective of good incomes. The current scenario, comprised of low crop diversity, fragile in face of droughts and plagues, can partially explain this opinion. The booklet was effective in catching people attention for the species potential. There was wide acknowledgement on the importance of alternative pesticides, justified by health security. Based on the assessed parameter in the results of this research, the treatments here utilized may be recommended as fungicides for safflower. Given the crop susceptibility to fungi in heavy rainy period, it is advised that its potential introduction on the region shall be focused on semiarid areas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The cowpea (Vigna unguiculata L. Walp) is a major food crops in northeastern Brazil. In Rio Grande do Norte, the cowpea, vigna beans or cowpea, as it is known, has great socioeconomic importance as a source of nutrients in food, with great emphasis among agricultural products. To improve productivity and resistance to pests, two cultivars were developed exclusively by EMPARN (Agricultural Research Corporation of Rio Grande do Norte), for breeding. The samples were provided by EMPARN, two improved (Potiguar and Laugh year) and two landraces (Rib of beef and Canapu). The seeds were ground and made into flour samples and the determination of moisture and ash by graviméticos methods, lipids by Soxhlet extraction, fibers with determiner fiber, carbohydrates by difference and minerals by ICP-OES were performed except the match analyzed by UVvis. The results showed a high fiber content (55.55% and 55.32% and 50.04% improved samples and 50.32% creole samples) and protein (25.52% and 25.27% improved and 27 samples, 23% and 24.99% creole samples). Comparing the results of the mineral content, the improved cultivars stood out in relation to Ca, Co, P, Mg, Mo and Na. Creole cultivars showed better results for Cu, Cr (low), Fe, Mn, Ni, K and Zn. The results will be important in future nutritional research and to build a table of Brazilian chemical composition of foods.