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61.

Background  

The repeated weekly subculture of plant cell suspension is labour intensive and increases the risk of variation from parental cells lines. Most of the procedures to preserve cultures are based on controlled freezing/thawing and storage in liquid nitrogen. However, cells viability after unfreezing is uncertain. The long-term storage and regeneration of plant cell cultures remains a priority.  相似文献   
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Global carbon trading may present a unique opportunity to change the rural landscape by allowing landowners to make an environmental impact with financial incentives. By enticing point source polluters to trade to an optimal level of pollution by offsetting their emissions with compatible carbon reduction projects, markets are able to facilitate a cleaner environment. Agroforestry provides a set of practices that can sequester carbon with managed tree and crop plantings. However, the initial lack of financial resources has been an obstacle to its adoption in the United States. This paper explores the potential for carbon offset trading to provide an added incentive to adopt agroforestry practices. Chicago Climate Exchange carbon sequestration projects are used as a baseline assessment, and the requirements that Missouri landowners would need to do in terms of contracting and ownership are identified. Data from landowners in central Missouri and the Ozarks (353 individuals) are used to determine characteristics of potentially interested landowners in agroforestry. A model to evaluate agroforestry profitability scenarios is used to compare the added carbon credit trading revenue to traditional alternate uses for the property. The findings from this analysis indicate that in the current context carbon trading does not provide an added incentive value for Missouri landowners to adopt either silvopasture or alley cropping practices because of the low magnitude of annual return.  相似文献   
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Genomes of animals as different as sponges and humans show conservation of global architecture. Here we show that multiple genomic features including transposon diversity, developmental gene repertoire, physical gene order, and intron-exon organization are shattered in the tunicate Oikopleura, belonging to the sister group of vertebrates and retaining chordate morphology. Ancestral architecture of animal genomes can be deeply modified and may therefore be largely nonadaptive. This rapidly evolving animal lineage thus offers unique perspectives on the level of genome plasticity. It also illuminates issues as fundamental as the mechanisms of intron gain.  相似文献   
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The efficacy of hexaflumuron, a benzophenylurea insecticide, has been studied for the first time on a fungus-growing termite (Pseudacanthotermes spiniger Sjöstedt, Macrotermitinae). Results show that hexaflumuron could be useful in treating infestations of such pest species, which are of great economic importance in many tropical and equatorial countries. Foraging workers harvested and introduced treated food into the nest and subsequently contaminated the brood by trophallaxis. Hexaflumuron showed potent larvicidal activity. The compound did not appear to be rapidly degraded by the digestive enzymes of termite workers, nor by the symbiotic fungus Termitomyces eurhizus Heim growing on fungus combs. This chitin synthesis inhibitor did not act as a fungicide, since growth of the mycelium of this fungus was not inhibited in vitro. © 1998 Society of Chemical Industry  相似文献   
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This report describes a case of Mycobacterium tuberculosis infection in a green-winged macaw (Ara chloroptera), confirmed by microbiologic and pathologic diagnostics, and notes a possible human-avian transmission. Clinical signs included cutaneous swellings, profound leukocytosis, and signs of osteomyelitis in the long bones. Proliferation consisted of several nodules with small greenish-caseous foci in cross-section and revealed a severe granulomatous inflammation with intralesional acid-fast rods. Mycobacterium tuberculosis was isolated from subcutaneous nodules and biochemically confirmed. The disease in avian species is of zoonotic importance.  相似文献   
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The protozoan parasite Toxoplasma (T.) gondii is one of the most common zoonotic infectious agents worldwide. Besides its sexual reproduction in cats, T. gondii can also infect a wide spectrum of other warm-blooded animals. These include animals used for human consumption such as pigs or chickens. Nevertheless, the role of turkeys for the epidemiology of T. gondii infections has not been studied thoroughly. We have established a kinetic ELISA (KELA) for the detection of T. gondii-specific IgG antibodies in turkey serum samples. The test is based on the recombinant dense granule antigens GRA7 and GRA8. These proteins were used as an antigen mixture at a concentration of 0.13 μg per well. The overall sensitivity of the assay was between 92.6% and 100% and the specificity ranged from 78.1% to 100%, depending on the method used to calculate these parameters. Using this KELA we examined 1913 turkey serum samples from 14 turkey farms from different areas of Germany. From these sera, 387 produced a signal in the KELA, corresponding to a true seroprevalence of up to 20.2%. The seropositivity rate in individual fattening cycles at individual farms ranged from 0.0% to 77.1%, whereas the rates were highly variable within the individual farms and individual fattening cycles. Consequently, conditions of animal husbandry could not be associated with particular seroprevalence rates. Although seropositivity cannot be linked directly to infectious tissue cysts in the muscle tissue of commercially produced turkey meat, we state that there is a potential risk of being infected by consuming turkey meat products that were not heat treated.  相似文献   
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North Sumatra and West Java in Indonesia, the Andes of Bolivia and Peru, Western Province, the Coast and Machakos in Kenya, were Small Ruminant Collaborative Research Support Program (SR-CRSP) sites in which the role of small ruminants was studied and where technological interventions were designed. In all cases the target groups were poor rural households that could maintain sheep, goats, or South American camelids. The objective was to increase the welfare of families through the use of small ruminant technologies. Access to and control of resources, and intrahousehold dynamics were analyzed to understand if, how, and when, technological interventions help achieve this objective. The way in which the studied villages integrate into the market, the specific role that livestock and other productive enterprises play in the household economy, the risks faced by families in rural areas condition the role of livestock and other resource management technologies. As an asset, small and large stock are gendered, but this is qualified by the alternatives that household members have. Small ruminants under the domain of women, either through production or marketing, are shown to contribute to in-kind consumption or, as liquid assets, to household welfare purchases, in the case of Andean agropastoral households and households in Kenya. Women are also managers of the grazing areas, which are often fallow fields. The research experiences show the relationship between gender, resource management, and the ability to build livestock assets and security, in different houehold production systems. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
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