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101.
ABSTRACT

In the heat treatment of oysters, many aroma compounds are lost in the cooking steam and water. In this study, aroma compound profiles from oyster processing were identified by gas chromatography- mass spectrometry (GC-MS). The compounds were extracted by headspace-solid phase microextraction (HS-SPME), while the best process conditions such as temperature, extraction time, and desorption time were studied. The aroma compounds were obtained from raw oysters, from oysters after thermal treatment, from water released from raw oysters, from cooking steam, and from oyster boiling juice. All compounds were identified and semi-quantified by GC-MS. The major oyster aroma compounds were 1-octen-3-ol, hexanal, and benzaldehyde. Most of the components from oysters were lost both to the cooking steam and to the oyster boiling juice. The concentration range of volatile organic compounds transferred for oyster boiling juice between 14 and 90 mg L?1 shows that the residues from oyster processing have great technological potential, and they can be recovered for application as aromas by the food industry.  相似文献   
102.
Fusarium verticillioides is one of the most important pathogens in maize and is a producer of fumonisin B1 (FB1). Although reports of its presence in wheat are scarce, the susceptibility of this cereal to fungus of the same genus motivates interest in investigating compounds present in the grain with inhibitory activity against this species. The aim of this study was to extract α‐amylase inhibitors from wheat and apply them in vitro to evaluate its effect on the development and expression of toxigenic potential of F. verticillioides. The α‐amylase inhibitors, both crude (P0) and purified (P1), were applied to in vitro culture containing a pathogen mycelium disc. Mycelial growth of the pathogen, glucosamine content, α‐amylase activity, and production of FB1 were investigated. All protein extracts of wheat showed the ability to inhibit pathogen growth, especially the extract P0 from cultivar Quartzo, which resulted in a reduction of glucosamine content (66%) and α‐amylase activity (84%). Furthermore, the protein inhibitors showed antifumonisin effect, reducing by 33 and 47% the mycotoxin production when applied as P0 and P1, respectively. These results suggest that α‐amylase inhibitor contributed to resistance against pathogen attack, acting in a diversified manner for each fungal species.  相似文献   
103.
Wheat is one of the major food crops in the world. It is Australia’s largest crop and most important agricultural commodity. In Australia the crop is grown under rainfed conditions with inherently important regional environmental differences; wheat growing areas are characterized by winter dominant rainfall in southern and western Australia and summer rainfall in northern Australia. Maximizing yield potential across these diverse regions is dependent upon managing, either genetically or agronomically, those factors in the environment that limit yield. The potential of synthetic backcross lines (SBLs) to increase yield in the diverse agroecological zones of Australia was investigated. Significant yield advantages were found for many of the SBLs across diverse environments. Depending on the environment, the yield of the SBLs ranged from 8% to 30% higher than the best local check in Australia. Apart from adaptation to semiarid water stressed conditions, some SBLs were also found to be significantly higher yielding under more optimal (irrigated) conditions. The four testing environments were classified into two groups, with the northern and southern environments being in separate groups. An elite group of SBLs was identified that exhibited broad adaptation across all diverse Australian environments included in this study. Other SBLs showed specific adaptation to either northern or southern Australia. This study showed that SBLs are likely to provide breeders with the opportunity to significantly improve wheat yield beyond what was previously possible in a number of diverse production environments.  相似文献   
104.
In South America, visceral leishmaniasis is a zoonosis caused by the protozoan species Leishmania infantum (syn. L. chagasi) and is primarily transmitted through the bite of the female Lutzomyia longipalpis. Its main reservoir in urban areas is the dog. The application of control measures recommended by health agencies have not achieved significant results in reducing the incidence of human cases, and the lack of effective drugs to treat dogs resulted in the prohibition of this course of action in Brazil. Therefore, it is necessary to search new alternatives for the treatment of canine and human visceral leishmaniasis. The objectives of this study were to evaluate the in vitro effect of fractions from Aloe vera (aloe), Coriandrum sativum (coriander), and Ricinus communis (castor) on promastigotes and amastigotes of L. infantum and to analyze the toxicity against the murine monocytic cells RAW 264.7. To determine the viability of these substances on 50% parasites (IC50), we used a tetrazolium dye (MTT) colorimetric assay (bromide 3-4.5-dimethylthiazol-2-yl-2,5-dephenyltetrazolium), and on amastigotes we performed an in situ ELISA. All fractions were effective against L. infantum promastigotes and did not differ from the positive control pentamidine (p>0.05). However, the R. communis ethyl acetate and chloroform fractions, as well as the C. sativum methanol fraction, were the most effective against amastigotes and did not differ from the positive control amphotericin B (p>0.05). The R. communis ethyl acetate fraction was the least toxic, presenting 83.5% viability of RAW 264.7 cells, which was similar to the results obtained with amphotericin B (p>0.05). Based on these results, we intend to undertake in vivo studies with R. communis ethyl acetate fractions due the high effectiveness against amastigotes and promastigotes of L. infantum and the low cytotoxicity towards murine monocytic cells.  相似文献   
105.
The aim of the present study was to evaluate the acaricidal efficacy of thymol on unengorged and engorged larvae and engorged nymphs of Amblyomma cajennense. To perform the test for unengorged larvae, the larval packet technique was employed and mortality was evaluated 24h after the test, while for engorged larvae and engorged nymphs the immersion technique was employed and mortality was evaluated after 15 days. In all the experiments, the following concentrations of thymol were tested: 2.5, 5.0, 10.0, 15.0 and 20.0mg the thymol/ml. The control group was exposed to water and 1% DMSO and there were 10 repetitions for each treatment. The values found for mortality of unengorged larvae were 18.2%, 51.8%, 97.6%, 93.5% and 94.5%, and for engorged nymphs the values were 26.0%, 92.2%, 100.0%, 100.0%, 100.0%, in concentrations of 2.5, 5.0, 10.0, 15.0 and 20.0mg of thymol/ml, respectively. In the test with engorged larvae, mortality was 100.0% in all treatments. Based on the results, it is possible to conclude that thymol has acaricidal activity against immature stages of A. cajennense.  相似文献   
106.
Gastrointestinal nematodes (GIN) of ruminants (cattle, sheep and goats) are ubiquitous and can cause severe injuries to infected animals and significant losses in farming revenues. GIN are able to survive severe environmental and host conditions, but mankind has developed a number of ingenious methods for parasite control. The commerce and use of modern anthelmintic drugs with a broad spectrum of activity has been a solid tool for nearly 40 years, however the continuous use of these drugs, has led to the selection of populations of drug-resistant worms worldwide. At present, the ever-growing agricultural systems in Latin America are facing many challenges and cannot rely on the far-reaching objective of parasitic elimination from the host or the environment. The lack of extensive programs for monitoring drug resistance exacerbates the negative consequences of reduced efficacy, which is evident in some areas with the increase in mortality rate even after treatment. Experts agree that new schemes of parasitic control are needed and should be based on the strategy of targeted selective treatment where affected hosts are identified and treated accordingly. In this article, we will focus our discussion on the challenges for the control of GIN in Latin America by 2020 imposed by reduced drug efficacy. We will evaluate phenotypic and molecular markers, methods for single-animal evaluation, and the implementation of schemes for anthelmintic treatment that address parasites in refugia.  相似文献   
107.
The circulation of West Nile virus in Portugal was assessed by serological surveys conducted during 2004-2010 in horses and birds. The detection of WNV antibodies in both species in all the years covered by the study as well as the presence of anti-WNV IgM in symptomatic horses that had not traveled outside the country, support the notion that WNV circulates in Portugal.  相似文献   
108.
Phosphorus, manganese, sulfur (S), lead, and strontium of atmospheric total suspended particulate matter, sampled during the rainy season and the dry season 2002 at the Ilha Grande Island (Rio de Janeiro State, Brazil) have been analyzed by XRF techniques. The results showed total mean concentrations of 27?±?16 ng P m-3, 11?±?7 ng Mn m-3, 159?±?126 ng S m-3, 4.3?±?2.6 ng Pb m-3, and 208?±?148 ng Sr m-3. Generally, there is no clear influence of the two different climatic periods on the concentrations of most analyzed trace elements, with exception of sulfur the mean concentration of which, during the dry season, is about 60% higher than during the rainy season. This is probably due to biomass burning, a common practice in the Brazilian Southeast and Amazon region and/or to the presence of marine aerosols. The linear correlation coefficients strongly suggest the same source for P, Pb, and Mn. Some Pb, Mn, and P concentrations are in the range of typical values of urban areas. Potential sources of such elements are the urban and industrial emissions from the States of Rio de Janeiro and/or São Paulo.  相似文献   
109.
Echinococcus granulosus infection is a problem of public health in livestock-rearing regions of Latin America, like in Peru. This species is characterized by the morphometry of the large and small rostellar hooks in both metacestodes and adult worms. The aim of this work was to study biometrical characteristics of rostellar hooks in hydatid cysts (lung and liver) from some Peruvian provinces (Arequipa, Cuzco, Huancavelica, Junin and Puno). The biometrical analysis was obtained in a digital system for image analysis. The following parameters were studied: area, perimeter, length and width total of the handle, the blade and the distance between the blade and the guard of large and small hooks. For statistical analysis Student's t-test and Analysis of Variance (ANOVA) with Pos-test of Tukey were used, considering the values of p< or =0.05 as of statistic significance. All morphometric characters of large and small hooks were highly significant (p<0.000), when data were compared among the samples from the different provinces. Rostellar hooks in specimens from Huancavelica presented smallest measurements, whereas hooks in specimens from Junin were bigger in relation to the total and blade measurements. Generally, samples from Arequipa presented the biggest large hooks in relation to the handle parameters. The rostellar hooks of cattle and sheep hosts varied depending on the geographic localization, host and organ. Hooks recovered from the lungs were larger than those collected in the liver. It was concluded that morphometry using computer image analysis allows the characterization of E. granulosus. The rostellar hooks presented morphometric polymorphism.  相似文献   
110.
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