929 resultados para LABORATORY CONDITIONS
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The preference of predation on oocytes of Piaractus mesopotamicus, commonly known as 'Pacucaranha', by the prawn Macrobrachium amazonicum, under laboratory conditions, was evaluated regarding to other food items. The prawns were collected with sieves, placed below the underwater vegetation, and maintained in aquarium (12 L each) at a density of 10 individuals/aquarium for acclimatization. Oocytes (O) of P. mesopotamicus were obtained from the disposal of artisanal fishery. Artificial feed (R), fish muscle (M), organic matter accumulated in roots of Salvinia sp. (S) and plant organic matter in decomposition (MV) items were used to compare the preference by M. amazonicum. In all experiments the average of the prawns preying oocytes were higher; significant differences were detected only when comparing O/P and O/M. The preference for oocytes may be due to the presence of yolk, which has a high nutritional value and easy assimilation, in contrast to others items, which resent certain rigidity. This prawn species is exotic on site and the results of this study shows a possible environmental impact on P. mesopotamicus in the region.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The interactions between the entomopathogenic fungus Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae McIntoch (Hymenoptera: Braconidae) were evaluated under laboratory conditions. Nymphs of Myzus persicae Sulzer (Hemiptera: Aphididae) were first exposed to parasitoid females for 24 h and then 0, 24, and 48 h afterwards sprayed with a solution of B. bassiana. Likewise, aphids were also sprayed with B. bassiana and then exposed to parasitoids at 0, 24, and 48 h afterwards. Parasitism rate varied from 13 to 66.5%, and were signi_cantly lower in treatments where the two agents were exposed within a 0-24 h time interval compared with the control (without B. bassiana). Parasitoid emergence was negatively affected in treatments with B. bassiana spraying and subsequent exposure to D. rapae. Decreases in longevity of adult females of the D. rapae F1 generation were observed in treatments with B. bassiana spraying. The application of these two biological control agents can be used in combination on the control of M. persicae, wherein this use requires effective time management to avoid antagonistic interactions.
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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Agronomic characteristics and commercial quality of popcorn maize cultivars. In order to identify popcorn cultivars that constitute a viable alternative For popcorn producers, an experiment was conducted using a randomized blocks experimental design with Five genotypes (BRS Angela, Zelia, IAC 112, IAC 12 and IAC TC-01) and four repetitions, during the 2003/2004 crop. The experiment was carried out with 60 cm spacing between lilies and density of 75 thousand plants per hectare. During the experiment, agronomic and commercial characteristics were evaluated, under field and laboratory conditions. The variety BRS Angela featured increased yield, followed by simple hybrids IAC, with Zelia (triple hybrid) showing lower yield. The simple hybrid IAC 12 showed the lowest commercial quality of popcorn. Grain production was positively associated with the number of grains per car and with the weigh of 1,000 grains, and negatively with the level of N(total) in grain. The commercial quality was negatively influenced by the weigh of 1,000 grains.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The aim of this work was to evaluate the types of resistance of soybean genotypes to the attack of Spodoptera cosmioides (Walker, 1858), under laboratory conditions. Plants of the soybean genotypes, IAC 100, Dowling, PI 227687, PI 274454, BR 16, IGRA RA 626 RR, PI 227682, BRSGO 8360, IGRA RA 516 RR e P 98Y11 RR, were cultivated in vases and placed in a greenhouse in order to have their leaves used afterwards in free-choice and no-choice no-preference for feeding tests and evaluation of the biological parameters of S. cosmioides fed on the genotypes. For free-choice no preference for feeding test, 10 leaf discs were prepared and placed in Petri dishes equidistantly among themselves, and then two recently-hatched caterpillar per genotype were release in the center of the plate. The same test was performed for third instar larvae, so that one caterpillar per genotype was used. In non-choice test, only one genotype was used in each Petri dish, where two recently-hatched or one third instar caterpillars were released, respectively. For both tests, the attractiveness was assessed at 1, 3, 5, 10, 15, 30, 60, 120, 360, 720 and 1440 minutes after the release of the insects. In addition, the leaf area consumed was evaluated. Randomized blocks design and completely randomized design were used for free-choice and non-choice tests, respectively, with 10 replications. In biology test, recently-hatched larvae were transferred to Petri dishes with leaves of the genotypes, evaluating the period of larvae, pupae and overall (larvae + pupae), viability of larvae, pupae and overall, weight of 12 days-old larvae and 24 hours-old pupae and longevity of the adults. Completely randomized design was used for this test, with 30 replications. Genotypes IGRA RA 516 RR and IGRA RA 626 RR were the least and the most consumed by recently-hatched larvae of S. cosmioides, respectively, in non-choice non-preference for feeding test. Genotypes PI 274454 and PI 227687 were...
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Among the sexual hormones the estrogens are receiving major attention due to their biological activity. Such biological response is atributed to the best conformation recognized by their receptors, resulting in maximum responses. The estrogens are also considered responsible for most of disruptor´s effects caused by their presence in aquatic ecosystems. The 17β-estradiol hormone is produced by vertebrates during the reproductive phase of their lives and its presence has been detected in superficial waters. The objective of this study was to evaluate the cause-effect of tilapia exposition to the hormone 17β-estradiol through the analysis of biotransformation enzymes in liver and gills, complemented with the quantification of 17β-estradiol and estrone in water samples collected from fish ponds integrated to swine production. The present study was conducted under laboratory conditions, in a randomized experimental design with three levels of 17β-estradiol (E2) (0, 5, 15 µg L-1), with three replicates. After 7 days of exposure time, liver and gills were extracted to analyze three isoforms of cytochrome P450: EROD, BROD, PROD and the activity of Glutathione S-Transferase (GST). The results showed that the EROD activity (CYP1A), normally induced by the metabolism of aromatic compounds, did not present statistical differences among the treatments exposed to E2, what means that the hormone did not induce isoform 1A in fish under these particular experimental conditions. PROD activity was significantly altered in both concentrations, by means of 5 and 15 µg L-1, when compared to control. This result can indicate an important role of PROD on the metabolism of E2 present in water. Regarding to the BROD activity, it could be observed differences statistically significant between control and both groups of treatments. Two or more CYP isoforms can contribute to the metabolism of the same compound, what makes BROD a candidate as a next bioindicator of the exposure to E2 in aquatic ecosystems. Analysis of variance could confirm the effect of E2 statistically significant on the GST activity in liver tissues with >90% of significance (Prob>F = 0.0753). Furthermore, it was possible to observe that the values of GSTs activities in liver and gills in both, control and treatments, follow a tendency, that means, enzymatic activity in gills increase as the increasing of the activity in the liver tissues. In this study, the 17β–estradiol was found in measurable concentrations in three sampled points, and these values were similar to the findings of other authors at different locations in Brazil. In addition, those values are much higher than the minimum concentration that presented observable effects (10 ng L-1).
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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Pós-graduação em Geociências e Meio Ambiente - IGCE
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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Pós-graduação em Agronomia (Proteção de Plantas) - FCA