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Lieselot Houspie Sarah De Coster Els Keyaerts Phouthalack Narongsack Rikka De Roy Ive Talboom Maura Sisk Piet Maes Jannick Verbeeck Marc Van Ranst 《Virology journal》2011,8(1):1-7
Background
Human enterovirus 71 (EV71) has emerged as a significant cause of acute encephalitis and deaths in young children. The clinical manifestations caused by EV71 varied from mild hand, foot and mouth disease to severe neurological complications and deaths, but its pathogenesis remains elusive. Antibody dependent enhancement (ADE) infection has been reported in various viruses and has been shown to contribute to disease severity.Results
In this study, the presence of sub-neutralizing antibody was demonstrated to enhance EV71 infection in THP-1 cells and increase the mortality of EV71 infection in a suckling mouse model. Further, a secondary infection model was established to characterize the correlation between ADE and disease severity, and primary asymptomatic EV71 infection was shown to increase the mortality of the secondary EV71 infection in suckling mice.Conclusions
Together, these in vitro and in vivo experiments strongly supported the hypothesis of ADE infection of EV71. The present findings indicate ADE might contribute to the pathogenesis of severe EV71 infection, and raise practical issues of vaccine development and antibody-based therapy. 相似文献22.
Troels K. H. Scheel Jannick Prentoe Thomas H. R. Carlsen Lotte S. Mikkelsen Judith M. Gottwein Jens Bukh 《PLoS pathogens》2012,8(5)
Hepatitis C virus (HCV) is an important cause of chronic liver disease. Several highly diverse HCV genotypes exist with potential key functional differences. The HCV NS5A protein was associated with response to interferon (IFN)-α based therapy, and is a primary target of currently developed directly-acting antiviral compounds. NS5A is important for replication and virus production, but has not been studied for most HCV genotypes. We studied the function of NS5A using infectious NS5A genotype 1–7 cell culture systems, and through reverse genetics demonstrated a universal importance of the amphipathic alpha-helix, domain I and II and the low-complexity sequence (LCS) I for HCV replication; the replicon-enhancing LCSI mutation S225P attenuated all genotypes. Mutation of conserved prolines in LCSII led to minor reductions in virus production for the JFH1(genotype 2a) NS5A recombinant, but had greater effects on other isolates; replication was highly attenuated for ED43(4a) and QC69(7a) recombinants. Deletion of the conserved residues 414-428 in domain III reduced virus production for most recombinants but not JFH1(2a). Reduced virus production was linked to attenuated replication in all cases, but ED43(4a) and SA13(5a) also displayed impaired particle assembly. Compared to the original H77C(1a) NS5A recombinant, the changes in LCSII and domain III reduced the amounts of NS5A present. For H77C(1a) and TN(1a) NS5A recombinants, we observed a genetic linkage between NS5A and p7, since introduced changes in NS5A led to changes in p7 and vice versa. Finally, NS5A function depended on genotype-specific residues in domain I, as changing genotype 2a-specific residues to genotype 1a sequence and vice versa led to highly attenuated mutants. In conclusion, this study identified NS5A genetic elements essential for all major HCV genotypes in infectious cell culture systems. Genotype- or isolate- specific NS5A functional differences were identified, which will be important for understanding of HCV NS5A function and therapeutic targeting. 相似文献
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Carbon Footprint 总被引:1,自引:0,他引:1
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Jannick H. Schmidt 《The International Journal of Life Cycle Assessment》2010,15(2):183-197
Background, aim and scope
The environmental effect of globalisation has been debated intensively in the last decades. Only few well-documented analyses of global versus local product alternatives exist, whilst recommendations on buying local are vast. At the same time, the European Environmental Agency’s Third Assessment concludes that the resource use within the EU is stabilising at the expense of increased resource use for import of products to the EU. Taking its point of departure in vegetable oils, this article compares rapeseed oil and palm oil as a local and a global alternative for meeting the increasing demand for these products in the EU. By using detailed life cycle assessment (LCA), this study compares the environmental impacts and identifies alternative ways of producing rapeseed oil and palm oil to the EU market in order to reduce environmental impacts. 相似文献27.
Verbeeck J Maes P Lemey P Pybus OG Wollants E Song E Nevens F Fevery J Delport W Van der Merwe S Van Ranst M 《Journal of virology》2006,80(9):4220-4226
Epidemiological and phylogenetic studies of hepatitis C virus (HCV) have identified six major HCV genotypes and have attempted to characterize their origin and spread worldwide. Putative regions of endemic infection have been identified for all HCV genotypes except HCV genotype 5a. Although HCV genotype 5a was previously thought to be largely restricted to the northern part of South Africa, this study reports an unexpected cluster of the genotype in West Flanders Province in Belgium. To investigate the molecular epidemiology of this cluster and of HCV genotype 5a in general, a rigorous phylogenetic analysis of Belgian and South African HCV genotype 5a samples was performed. Remarkably, the Belgian and South African strains form two distinct clusters of similar diversity. We used a Bayesian coalescent method to estimate the rate of virus spread through time for HCV genotype 5a in both regions. Our results indicate that HCV genotype 5a strains have been spreading independently in Belgium and South Africa for more than 100 years, with a rate of spread characteristic of an epidemic genotype. These findings have major implications for tracing the origin of HCV genotype 5a. Here, we speculate about the possible origins of these clusters. 相似文献
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Jannick H. Schmidt 《The International Journal of Life Cycle Assessment》2008,13(4):350-364
Background, aim, and scope
When dealing with system delimitation in environmental life cycle assessment (LCA), two methodologies are typically referred to: consequential LCA and attributional LCA. The consequential approach uses marginal data and avoids co-product allocation by system expansion. The attributional approach uses average or supplier-specific data and treats co-product allocation by applying allocation factors. Agricultural LCAs typically regard local production as affected and they only include the interventions related to the harvested area. However, as changes in demand and production may affect foreign production, yields and the displacement of other crops in regions where the agricultural area is constrained, there is a need for incorporating the actual affected processes in agricultural consequential LCA. This paper presents a framework for defining system boundaries in consequential agricultural LCA. The framework is applied to an illustrative case study; LCA of increased demand for wheat in Denmark. The aim of the LCA screening is to facilitate the application of the proposed methodology. A secondary aim of the LCA screening is to illustrate that there are different ways to meet increased demand for agricultural products and that the environmental impact from these different ways vary significantly.Materials and methods
The proposed framework mainly builds on the work of Ekvall T, Weidema BP (Int J Life Cycle Assess 9(3):pp. 161–171, 2004), agricultural statistics (FAOSTAT, FAOSTAT Agriculture Data, Food and Agriculture Organisation of the United Nations (2006), http://apps.fao.org/ (accessed June)), and agricultural outlook (FAPRI, US and world agricultural outlook, Food and Agriculture Research Institute, Iowa, 2006a). The framework and accompanying guidelines concern the suppliers affected, the achievement of increased production (area or yield), and the substitutions between crops. The framework, which is presented as a decision tree, proposes four possible systems that may be affected as a result of the increased demand of a certain crop in a certain area.Results
The core of the proposed methodology is a decision tree, which guides the identification of affected processes in consequential agricultural LCA. The application of the methodology is illustrated with a case study presenting an LCA screening of wheat in Denmark. Different scenarios of how increased demand for wheat can be met show significant differences in emission levels as well as land use.Discussion
The great differences in potential environmental impacts of the analysed results underpin the importance of system delimitation. The consequential approach is appointed as providing a more complete and accurate but also less precise result, while the attributional approach provides a more precise result but with inherent blind spots, i.e. a less accurate result.Conclusions
The main features of the proposed framework and case study are: (1) an identification of significant sensitivity on results of system delimitation, and (2) a formalised way of identifying blind spots in attributional agricultural LCAs.Recommendations and perspectives
It is recommended to include considerations on the basis of the framework presented in agricultural LCAs if relevant. This may be done either by full quantification or as qualitative identification of the most likely ways the agricultural product system will respond on changed demand. Hereby, it will be possible to make reservations to the conclusions drawn on the basis of an attributional LCA. 相似文献29.
LCA of soybean meal 总被引:2,自引:0,他引:2
Randi Dalgaard Jannick Schmidt Niels Halberg Per Christensen Mikkel Thrane Walter A. Pengue 《The International Journal of Life Cycle Assessment》2008,13(3):240-254
Background, Aim and Scope Soybean meal is an important protein input to the European livestock production, with Argentina being an important supplier.
The area cultivated with soybeans is still increasing globally, and so are the number of LCAs where the production of soybean
meal forms part of the product chain. In recent years there has been increasing focus on how soybean production affects the
environment. The purpose of the study was to estimate the environmental consequences of soybean meal consumption using a consequential
LCA approach. The functional unit is ‘one kg of soybean meal produced in Argentina and delivered to Rotterdam Harbor’.
Materials and Methods Soybean meal has the co-product soybean oil. In this study, the consequential LCA method was applied, and co-product allocation
was thereby avoided through system expansion. In this context, system expansion implies that the inputs and outputs are entirely
ascribed to soybean meal, and the product system is subsequently expanded to include the avoided production of palm oil. Presently,
the marginal vegetable oil on the world market is palm oil but, to be prepared for fluctuations in market demands, an alternative
product system with rapeseed oil as the marginal vegetable oil has been established. EDIP97 (updated version 2.3) was used
for LCIA and the following impact categories were included: Global warming, eutrophication, acidification, ozone depletion
and photochemical smog.
Results Two soybean loops were established to demonstrate how an increased demand for soybean meal affects the palm oil and rapeseed
oil production, respectively. The characterized results from LCA on soybean meal (with palm oil as marginal oil) were 721
gCO2 eq. for global warming potential, 0.3 mg CFC11 eq. for ozone depletion potential, 3.1 g SO2 eq. for acidification potential, −2 g NO3 eq. for eutrophication potential and 0.4 g ethene eq. for photochemical smog potential per kg soybean meal. The average area
per kg soybean meal consumed was 3.6 m2year. Attributional results, calculated by economic and mass allocation, are also presented. Normalised results show that
the most dominating impact categories were: global warming, eutrophication and acidification. The ‘hot spot’ in relation to
global warming, was ‘soybean cultivation’, dominated by N2O emissions from degradation of crop residues (e.g., straw) and during biological nitrogen fixation. In relation to eutrophication
and acidification, the transport of soybeans by truck is important, and sensitivity analyses showed that the acidification
potential is very sensitive to the increased transport distance by truck.
Discussion The potential environmental impacts (except photochemical smog) were lower when using rapeseed oil as the marginal vegetable
oil, because the avoided production of rapeseed contributes more negatively compared with the avoided production of palm oil.
Identification of the marginal vegetable oil (palm oil or rapeseed oil) turned out to be important for the result, and this
shows how crucial it is in consequential LCA to identify the right marginal product system (e.g., marginal vegetable oil).
Conclusions Consequential LCAs were successfully performed on soybean meal and LCA data on soybean meal are now available for consequential
(or attributional) LCAs on livestock products. The study clearly shows that consequential LCAs are quite easy to handle, even
though it has been necessary to include production of palm oil, rapeseed and spring barley, as these production systems are
affected by the soybean oil co-product.
Recommendations and Perspectives We would appreciate it if the International Journal of Life Cycle Assessment had articles on the developments on, for example,
marginal protein, marginal vegetable oil, marginal electricity (related to relevant markets), marginal heat, marginal cereals
and, likewise, on metals and other basic commodities. This will not only facilitate the work with consequential LCAs, but
will also increase the quality of LCAs. 相似文献
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