Κυριακή, 2 Οκτωβρίου 2016

Immunostimulatory activity of brown seaweed-derived fucoidans at different molecular weights and purity levels towards white spot syndrome virus (WSSV)in shrimp Litopenaeus vannamei

2016-10-02T06-42-59Z
Source: Journal of Applied Pharmaceutical Science
Ellya Sinurat, Endang Saepudin, Rosmawaty Peranginangin, Sumi Hudiyono.
White spot syndrome virus (WSSV) is one of the virulent pathogens and causes big economic losses to shrimp aquaculture (Flegel, 2011). In general, most crustaceans have no immune system memory and only rely on innate immunity to protect themself against pathogen infection and other external factors that constantly threatens their lives (Sarathi et al., 2007). Research in the immune response of shrimp has flourished because of its importance in aquaculture and the increasing number of pathogens that arise are found, which may affect an organism's defense system (Bachere et al., 2000). To fight these pathogens, the shrimp using a variety of specific immune mechanisms, including haemocytes mobilization (Johansson and Soderhall, 1989); prophenoloxidase cascade formation (Sritunyalucksana and Soderhall, 2000). The immune system of shrimp is intimately related to its blood (hemolymph), because it contains haemocytes involved in cell's defense mechanisms such as phagocytosis, lysis of foreign units and encapsulation (Soderhall and Smith, 1983; Fuhua and Jianhai, 2013; Dechamag et al., 2006). Prophenoloxidase (proPO) system is an important defense mechanism in crustaceans. This system involves a complex molecular cascade triggered by components of the surface of immunostimulants. A number of immunostimulants that have been used in aquaculture are from the class of polysaccharides derived from bacteria and fungi such as -glucan, lipopolysaccharide (LPS), peptidoglycan, Cynodon dactylon and herbal immunostimulant. In addition to that, there are also immunostimulants derived from seaweeds such as alginate, carrageenan, laminarin and fucoidan. Generally immunostimulatory substances that have been reported so far were less pure or in the form of crude extracts (Chin et al., 2013). Fucoidan has no direct effect on virion, but it plays a role in the defense system through cellular and the humolar mechanisms to fight the virus. Mechanism of antiviral activity of fucoidan is to inhibit the absorption of viruses and the formation of virus-induced syncytium (Mandal et al., 2007). The biologic activities of fucoidans are closely related to their molecular structures, which include fucose linkage, the sugar type, sulfate content, and molecular weight. Among these, molecular weight is one of the most important factors determining the biological activities of polysaccharides.


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