Monoclonal antibodies directed to fucoidan preparations from brown algae

Cell walls of the brown algae contain a diverse range of polysaccharides with useful bioactivities. The precise structures of the sulfated fucan/fucoidan group of polysaccharides and their roles in generating cell wall architectures and cell properties are not known in detail. Four rat monoclonal antibodies, BAM1 to BAM4, directed to sulfated fucan preparations, have been generated and used to dissect the heterogeneity of brown algal cell wall polysaccharides. BAM1 and BAM4, respectively, bind to a non-sulfated epitope and a sulfated epitope present in the sulfated fucan preparations. BAM2 and BAM3 identified additional distinct epitopes present in the fucoidan preparations. All four epitopes, not yet fully characterised, occur widely within the major brown algal taxonomic groups and show divergent distribution patterns in tissues. The analysis of cell wall extractions and fluorescence imaging reveal differences in the occurrence of the BAM1 to BAM4 epitopes in various tissues of Fucus vesiculosus. In Ectocarpus subulatus, a species closely related to the brown algal model Ectocarpus siliculosus, the BAM4 sulfated epitope was modulated in relation to salinity levels. This new set of monoclonal antibodies will be useful for the dissection of the highly complex and yet poorly resolved sulfated polysaccharides in the brown algae in relation to their ecological and economic significance

Food Crisis and Export Taxation. Revisiting the adverse effects of non-cooperative aspect of Trade Policies

In this paper, we focus on the use of food security as a justification for export taxation. During food crisis, governments of food-exporting countries are tempted to react to high food prices by restricting exports. This is to encourage local producers to sell food items domestically and to decrease local prices, which implies higher world food prices. This measure amplifies a food crisis and is typically a “beggar-thy-neighbor” policy. But in times of food crisis, food-importing countries also decrease import duties to decrease domestic food prices; this causes food demand on the world market to increase, further reinforcing the upwards pressure on world food prices. The combination of export taxes and reduced import duties increases the upward pressure on world prices when food prices are high. On the contrary, in times of low world agricultural prices, food-exporting countries may be tempted to decrease export taxes and food-importing countries to increase import duties. Trade policies make world markets structurally more volatile. We also focus on the institutional aspect and, in particular, why export taxes can be raised so easily. It appears that countries have a relatively large degree of freedom when implementing export taxes as the WTO does not prohibit export taxes and other forms of export restrictions