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51.
An equimolar inclusion complex between imazalil, a selected fungicide, and beta-cyclodextrin using an aqueous standard solution procedure has been obtained. The complex has been investigated in solution by (1)H and (13)C NMR techniques in combination with computational methods in order to establish a valuable analytical protocol through which to gain insight into the interactions of the inclusion complex in aqueous solution. Intramolecular NMR distance constraints have been detected and used for three-dimensional complex structure determination.  相似文献   
52.
The root-knot nematode Meloidogyne incognita (Kofoid et White) Chitw. is responsible for large yield losses in several horticultural crops. Fumigation with chemicals has been efficient in fighting this soil pest, but it clearly shows a negative environmental impact. Thus, it is necessary to find an environmentally friendly alternative to control this nematode and meet the requirements imposed by world regulation to ban some chemical fumigants in the world after 2005. The glucosinolate-myrosinase system, typical of the Brassicaceae family, appears to be an important natural alternative for the control of several soilborne pests and pathogens. The aim of this study was to evaluate, in vitro, the biocidal activity of 11 glucosinolates and their degradation products on second-stage juveniles of the root-knot nematode M. incognita expressed by the nematicidal (LD(50)) and immobilization effects, after 24 and 48 h. None of the intact glucosinolates had any biological effect. After myrosinase addition, their hydrolysis products (essentially isothiocyanates) resulted in highly different biocidal activities. Among the hydrolysis products of the tested glucosinolates, 2-phenylethyl, benzyl, 4-methylthiobutyl, and prop-2-enyl isothiocyanate showed the stronger activity, with an LD(50) at concentrations of 11, 15, 21, and 34 microM, respectively. On the basis of the in vitro test results, new genotypes of Brassicaceae had been selected for high content in the roots of the glucosinolates generating the more active isothiocyanates and their agronomic performances verified in view of a full-field application as catch crop plants. With this aim, the qualitative and quantitative glucosinolate contents in the roots of these potentially nematicidal plants are also reported and discussed.  相似文献   
53.
Adsorption and desorption of triasulfuron by soil   总被引:10,自引:0,他引:10  
The adsorption and desorption of the herbicide triasulfuron [2-(2-chloroethoxy)-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]benzenesulfonamide] by three soils, soil organic matter (H(+) and Ca(2+)-saturated), and an amorphous iron oxide were studied. Adsorption isotherms conformed to the Freundlich equation. It was found that pH is the main factor influencing the adsorption in all of the systems. Indeed, the adsorption on soils was negatively correlated with pH. The highest level of adsorption was measured on soils with low pH and high organic carbon content. Moreover, it was found that humic acid is more effective in the adsorption compared with calcium humate (the pH values of the suspensions being 3.5 and 6, respectively). Experiments on amorphous iron oxide confirmed the pH dependence. Desorption was hysteretic on soils having high organic carbon content.  相似文献   
54.
55.
The aortic arrangement is an important structure associated with the maintenance of homeostasis. Based on this information, this study was conducted to describe the collateral arteries of the aortic arch of Antillean manatee and define the standard model for the species. Three specimens, an adult male, adult female and a male neonate, all strandings on the coast of the state of Rio Grande do Norte, Brazil, were used. The study was performed in the Laboratory of Morphophysiology of Vertebrates of the Federal University of Rio Grande do Norte, where in situ photographs were taken to demonstrate their topography. Subsequently, their hearts were removed and fixed in 10% formaldehyde and after 72 hr were dissected and analysed, obtaining schematic drawings and photographs of the vascular arrangement. The aortic arch was represented by three collateral arteries identified as the brachiocephalic trunk, left common carotid artery and left subclavian artery. This arrangement was similar to that found for other sirenians, and yet, for other mammals like hooded seal, murine, margarita island capuchin, black-handed tamarin, Mongolian gerbil and human. The morphological similarity presented in this study with different species of mammals, including humans, may contribute valuable information from an evolutionary point of view.  相似文献   
56.

We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus, X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage.

  相似文献   
57.
3,5-O-dicaffeoyl-4-O-malonilquinic acid (1) (irbic acid) has been isolated for the first time from cell cultures of Centella asiatica and till now it has never been reported to be present in the intact plant. Evidence of its structure was obtained by spectroscopic analyses (MS/NMR). Besides 1, cell cultures produce also the known 3,5-O-dicaffeoylquinic acid, chlorogenic acid, and the triferulic acid 2 (4-O-8′/4′-O-8″-didehydrotriferulic acid). Biological activities were evaluated for compound 1, which showed to have a strong radical scavenging capacity, together with a high inhibitory activity on collagenase. This suggests a possible utilization of this substance as a topical agent to reduce the skin ageing process.  相似文献   
58.
Feral swine (Sus scrofa) pose a significant disease threat to livestock and humans. Emerging technologies to reduce feral swine disease transmission risks include fertility control, vaccination, and toxicants. However, for these technologies to be appropriate for field application, a feral swine-specific oral delivery system is needed. We used two field trials to generate information related to appropriate field application of the Boar-Operated-System (BOS?), an oral delivery system designed to provide bait access only to feral swine. Our objectives were to determine whether pre-baiting BOS? units increased bait removal and to evaluate the proportion of feral swine and non-target animals that ingest baits designed to deliver pharmaceuticals through the BOS?. During both trials we used baits housed within 10 BOS? units. We monitored wildlife visitation, bait removal, and ingestion using motion sensing digital photography and baits containing the bait marker tetracycline hydrochloride (TH). During trial 1 we found three of five pre-baited BOS? units were used by feral swine only. Additionally, we found the five BOS? units that were not pre-baited were not used by feral swine or non-target wildlife. During trial 2 we determined bait removal from the BOS? to be reduced by only 10% for feral swine when activated, whereas bait removal from the BOS? by all other wildlife was reduced by 100% when activated. We captured 81 feral swine and 23 raccoons and found 90% and 13% to have TH-marked teeth, respectively. With minor modifications, the BOS? should be considered a valuable tool to be used in feral swine disease management in conjunction with existing technologies.  相似文献   
59.
Diatoms are dominant photosynthetic organisms in the world’s oceans and represent a major food source for zooplankton and benthic filter-feeders. However, their beneficial role in sustaining marine food webs has been challenged after the discovery that they produce secondary metabolites, such as polyunsaturated aldehydes (PUAs), which negatively affect the reproductive success of many invertebrates. Here, we report the effects of two common diatom PUAs, heptadienal and octadienal, which have never been tested before at the molecular level, using the sea urchin, Paracentrotus lividus, as a model organism. We show that both PUAs are able to induce teratogenesis (i.e., malformations), as already reported for decadienal, the better-studied PUA of this group. Moreover, post-recovery experiments show that embryos can recover after treatment with all three PUAs, indicating that negative effects depend both on PUA concentrations and the exposure time of the embryos to these metabolites. We also identify the time range during which PUAs exert the greatest effect on sea urchin embryogenesis. Finally, we report the expression levels of thirty one genes (having a key role in a broad range of functional responses, such as stress, development, differentiation, skeletogenesis and detoxification processes) in order to identify the common targets affected by PUAs and their correlation with morphological abnormalities. This study opens new perspectives for understanding how marine organisms afford protection from environmental toxicants through an integrated network of genes.  相似文献   
60.
Since ancient times, barley has been an important food resource for the people of Sardinia. The oldest traces of its cultivation are from the mid-Neolithic (fourth millennium B.C.). Archaeological, historical and anthropological aspects of barley cultivated in Sardinia are discussed in this paper. We describe the traditional process for making barley bread (orgiathu) in Sardinia, where a special starter called ghimisone was prepared. Today, barley is cultivated only as animal feed, with two uses, grain yield and grazing. Many farmers prefer to grow local populations belonging to landrace locally known as S' orgiu sardu. Local Sardinian populations of barley evolved in diverse environments, being cultivated from sea-level up to 1000 m elevation, on various soil types at different intensities of abiotic stresses, and with climates and environments associated with various agricultural practices, depending both on production strategies and climatic conditions. These barley materials are thought to be valuable genetic and cultural inheritance which must be preserved and used for both productive and research purposes.  相似文献   
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