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101.
102.
Paula Aguilera Fernando Borie Alex Seguel Pablo Cornejo 《Soil biology & biochemistry》2011,43(12):2427-2431
Arbuscular mycorrhizal spores and glomalin-related soil protein (GRSP) isolated from acid soils were analyzed using confocal laser scanning microscopy (CLSM) for Al detection. Mycorrhizal structures of Glomus intraradices produced under in vitro conditions as well as spores and GRSP from neutral and Cu-polluted soils were used as contrasting criteria. Spores and GRSP from soils with 7 and 70% Al saturation showed autofluorescence which increased especially at the highest soil Al level and when Al3+ solution was added. G.intraradices spores showed fluorescence only when exogenous Al3+ was added. On the contrary, spores and GRSP from neutral and Cu-polluted soils showed little or no significant fluorescence. This fluorescence shown by fungal structures and GRSP when subjected to high Al (of endogenous or exogenous origin) suggest a high capacity for Al immobilization, which could be an effective way to reduce Al activity and phytotoxicity in acid soils. 相似文献
103.
Jaime A. Ocampo-Hernández Patricia Tamez-Guerra Samuel Pineda Fernando Tamayo-Mejía Ariel Guzmán-Franco José I. Figueroa de la Rosa Ana Mabel Martínez 《Journal of pest science》2011,84(4):471-477
Entomopathogenic fungi represent excellent candidates for biological insecticides. Among the many entomopathogenic fungi, Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) is one of the most promising species. Here, we report the results of infection studies performed using four B. bassiana native isolates (Bb37, Bb38, Bb40, and Bb45) compared with the commercial product Mycotrol® (strain GHA) on adult Mexican bean beetle Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), one of the most important pests of bean production in Mexico. First, single concentration (1 × 108 conidia mL?1) assays were carried out using all isolates applied using an immersion method. Examinations at 10 days after inoculation indicated that isolates Bb37, Bb38, and Bb40 significantly reduced adult survival, causing 60–75% mortality compared to the commercial strain GHA (33%) and control (29%). Second, using two selected isolates (Bb37 and Bb40), the mean lethal concentration values (LC50) were estimated for third instar larvae and adult E. varivestis. The LC50 values for Bb37 and Bb40 isolates decreased 5.26-fold and 3.19-fold, respectively, in third instars compared with adults. However, such difference for Bb40 isolate was not significant. Finally, an experiment, to compare the median survival time (MST) values between third instar and adult E. varivestis, was conducted using Bb37 and Bb40 at 1 × 109 conidia mL?1. MST values were significantly reduced against larvae (87 and 100 h) compared with adults (130 and 134 h) by Bb37 and Bb40, respectively. We conclude that native isolates of B. bassiana represent an important alternative for the control of E. varivestis. However, to demonstrate its effectiveness under field conditions, detailed studies are needed. 相似文献
104.
Barbosa J Freitas A Moura S Mourão JL Noronha da Silveira MI Ramos F 《Journal of agricultural and food chemistry》2011,59(22):11927-11934
Nitrofurans were broadly used as an extremely effective veterinary antibiotic especially in pig and poultry production farms. Because of fears of the carcinogenic effects on humans, the nitrofurans were banned from use in livestock production in many countries, including the European Union. The present study examines the accumulation, distribution, and depletion of furaltadone and nifursol and of their tissue-bound metabolites [3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) and 3,5-dinitro-salicylic acid hydrazine (DNSAH), respectively, in poultry edible tissues (muscle, liver, and gizzards) following administration to chickens of therapeutic and subtherapeutic concentrations of both compounds. Nitrofurans determination was performed by high-performance liquid chromatography-diode array detection and liquid chromatography-tandem mass spectrometry, respectively, for feeds and for poultry tissues. Furaltadone and nifursol, in very low concentrations, were found in samples of muscle, liver, and chicken's gizzard collected from slaughtered animals after 5 weeks of treatment and no withdrawal time period. When a withdrawal time period of 3 weeks was respected, no detectable nitrofuran parent compounds was observed in all of the studied matrices. For AMOZ, concentrations of 270 μg/kg in meat, 80 μg/kg in liver, and 331 μg/kg in gizzard were determined after administration of a medicated feed with furaltadone (132 mg/kg), 3 weeks after withdrawal of treatment. For DNSAH, the concentration values obtained are much lower than those observed for AMOZ. For meat, liver, and gizzard, DNSAH concentrations of 2.5, 6.4, and 10.3 μg/kg, respectively, were determined, after administration of a medicated feed with nifursol (98 mg/kg), 3 weeks after withdrawal of treatment. The gizzard could be considered a selected matrix for nitrofuran residues evaluation in poultry, due to its capacity of retaining either nitrofuran parent compounds or metabolites in higher concentrations, regardless of the administered dose or of the respected withdrawal time period. 相似文献
105.
106.
Junia Vianna Corrêa da Silva Fernando César Juliatti João Renato Vaz da Silva Fernanda Carvalho Barros 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):409-418
Soybean rust is caused by an obligate parasite (Phakopsora pachyrhizi) which has spread in Brazil in each new season since 2001 and, despite the efforts to control the disease, losses have occurred
every year. Its control demands several tactics amongst which chemical control with fungicides is the main method and remains
indispensable. Control strategies such as the use of cultivars with partial resistance are desirable, but are not yet commercially
available. The present study analyzed the existing differences in the reactions of short, medium and long cycle soybean cultivars
against Asian rust and their responses to fungicide sprays. The experiment was conducted at Uberlandia-MG, Brazil, under field
conditions from December 2007 to May 2008, in the Syngenta Seeds Experimental Station. The high pressure of the disease in
the experiment simulated the natural pressure that the disease often reaches in Brazil. The studied variables were: visual
severity (percentage of infected leaf area), percentage defoliation and productivity (kg ha−1). Disease severity was expressed as AUDPC (area under disease progress curve). Variance analysis and comparison of means
by the Tukey test (5% significance) were done for all variables studied. Significant differences were observed between cultivar
effects and chemical control programs. The results obtained here indicate that the cultivars M-Soy 8199RR and Emgopa 315RR
were less susceptible to disease, and that a control program termed “monitoring” (in which the appearance of new pustules
of the pathogen were monitored to make the decision at each fungicide spray) was the most effective. 相似文献
107.
Vallejo F Tomas-Barberan F Garcia-Viguera C 《Journal of agricultural and food chemistry》2003,51(10):3029-3034
Total aliphatic and indole glucosinolates, phenolic compounds (flavonoids and hydroxycinnamoyl derivatives), and vitamin C contents were evaluated in freshly harvested broccoli (Brassica oleracea L., var. italica, cv. Marathon) inflorescences. These were film-wrapped and stored for 7 days at 1 degrees C to simulate a maximum period of commercial transport and distribution. After cold storage, inflorescences were kept for 3 days at 15 degrees C to simulate a retail sale period. For wrapping, low-density polyethylene (LDPE) of 11 microm thickness was used. Gas composition was about 17% O(2) and 2% CO(2) during cold storage and about 16% O(2) and 3-4% CO(2) during shelf life within packages. The predominant glucosinolates were 4-methylsulfinylbutyl-glucosinolate (glucoraphanin), 3-indolylmethyl-glucosinolate (glucobrassicin), and 1-methoxy-3-indolylmethyl-glucosinolate (neoglucobrassicin). The predominant hydroxycinnamoyl derivatives were identified as 1,2,2'-trisinapoylgentiobiose, 1,2-diferuloylgentiobiose, 1,2'-disinapoyl-2-feruloylgentiobiose, and 3-O-caffeoyl-quinic (neochlorogenic acid). Results showed major losses at the end of both periods, in comparison with broccoli at harvest. Thus, the respective losses, at the end of cold storage and retail periods, were 71-80% of total glucosinolates, 62-59% of total flavonoids, 51-44% of sinapic acid derivatives, and 73-74% caffeoyl-quinic acid derivatives. Slight differences in all compound concentrations between storage and retail sale periods were detected. Distribution and retail periods had minimal effects on vitamin C. Weight loss was monitored at the end of both periods. 相似文献
108.
We investigated spatio-temporal variability in the abundances and biomasses of four species of inshore serranids (the dusky grouper Ephinephelus marginatus, the island grouper Mycteroperca fusca, the painted comber Serranus scriba, and the blacktail comber S. atricauda) throughout the Canarian Archipelago (central-east Atlantic Ocean) with underwater visual transects. By means of a multiscaled sampling design spanning three orders of magnitude of spatial variability (from 10 s of meters among replicated 100 m2 transects to 100 s of kilometres among islands) and four sampling periods, we related differences in the distributions of serranids to differences in the degree of human pressure, such as fishing intensity and human population. Differences in human pressure among islands provide the most parsimonious explanation for many of the consistent inter-island differences in the abundance and biomass of the analyzed species. Larger-bodied serranids (E. marginatus and M. fusca) are more vulnerable than the smaller species (S. scriba and S. atricauda). In fact, the larger, more vulnerable species have been almost completely extirpated from the most intensely fished islands. Our results show that the larger groupers have been overexploited throughout the Canary Islands, and highlight the urgent need for stringent management measures and better control of littoral reef fish resources. 相似文献
109.
Michael D. Seymour Steven A. Schubert J. Wesley Clayton Jr. Quintus Fernando 《Water, air, and soil pollution》1978,10(2):147-161
The major acid components in the rain water collected during five different rainfall events in July and August 1977, were found to be a strong acid, the weak acid NH in4 su+ and dissolved CO2 from the atmosphere. Variations in their concentrations were determined as a function of time in the course of each of the rainfall events. Two experimental methods were used in this investigation, a microtitrim etric method and a coulometric method, and the data were analyzed by the use of modified Gran functions. Both methods gave the same results. The most significant observation was that the strong acid concentration increased from very low values to a maximum and then decreased in the course of a single rainfall event. 相似文献
110.
María Ferriol Maria Belén Picó Fernando Nuez 《Genetic Resources and Crop Evolution》2003,50(3):227-238
Increasing the knowledge of the molecular diversity of a crop is essential for extending its genetic base, identifying cultivars and selecting parental varieties for breeding programs. In this sense, Cucurbita maxima Duch. is poorly characterised. Nineteen accessions of this species and 8 related Cucurbita accessions were included in a genetic diversity analysis. For this purpose, Random Amplified Polymorphic DNA markers (RAPDs), which analyse neutral variability, and Sequence-Based Amplified Polymorphism (SBAPs), which preferentially amplify coding regions of the genome, were used. While the UPGMA cluster and the principal coordinates analysis obtained using RAPDs did not group the different accessions according either to fruit morphological criteria or to passport data (origin and agro-climatic conditions), the principal coordinates analysis obtained using SBAPs grouped the different pumpkin accessions fundamentally according to the type of use (human consumption, animal fodder or ornamental). This passport trait is reported to be associated with agronomic breeding characters of interest. The usefulness of both types of markers for discriminating accessions of breeding interest is discussed. 相似文献