Crustacean shellfish

Crustacean shellfish Shrimps Prawns Crabs Lobsters Crayfish Barnacles... 

FIGURE 4.1 Percent identity matrix for tropomyosins from molluscan shellfish, crustacean shellfish, insects and mites, and vertebrate sources. Compiled with the assistance of John C. Wise, Bioinformatics Specialist, University of Nebraska, Food Allergy Research Resource Program. 

Cross-reactivity between molluscan and crustacean shellfish species also occurs rafher frequently. Since tropomyosin is the major allergen in both molluscan and crustacean shellfish, fhe frequency of cross-reactions is not surprising. Allergy to crustacean shellfish is more frequenfly diagnosed than molluscan shellfish allergy (Hefle et ah, 2007). Many of fhese individuals may be at risk of reactions fo molluscan shellfish also. Appropriately, most individuals with either molluscan or crustacean shellfish allergy are advised to avoid all shellfish. 

Some animals, however, do not have hemoglobin to carry oxygen through the blood. For example, crustaceans (shellfish like lobsters, shrimps, and crabs) use a compound called hemocyanin. Hemocyanin is similar to hemoglobin but contains copper instead of iron. Many copper compounds, including hemocyanin, are blue. Therefore, the blood of a crustacean is blue, not red. 

Stingrays live in warm temperate and tropical zones in a great abundance. Their mouth is positioned on the undersurface of their body, making it easier to find food on or in the sandy bottoms of the ocean. Rays feed on live crustaceans, shellfish and other invertebrates. Instead of teeth, rays have crushing plates that allow them to grind their food. 

The polysaccharides are widely distributed in nature and have been regarded as structural materials and as suppliers of energy [1]. Because of better recent understanding of their possessing unique structures and properties, much attention has been paid to them as material sources. Of the many kinds of polysaccharides, chitin, a structural polymer in crustaceans, shellfish, and insects, is one of the most abundant natural polysaccharides in nature [2-6]. Despite its huge annual production and easy accessibility, chitin still remains an unutilized biomass resource primary because of its intractable bulk structure and insolubility in water and common organic solvents, and thus, only limited application has been paid to chitin, principally from its biological properties [7]. 

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