Invertebrate polar marine

Lippert, H., Brinkmeyer, R., and Iken, K. (2003). Antimicrobial activity in sub-Arctic marine invertebrates. Polar Biol. 26,591-600. 

Owing to their intrinsic basicity, marine invertebrate guanidine alkaloids have a rather polar behavior and their isolation from complex mixtures may be difficult. Isolation procedures frequently include chromatography on lipophilic Sephadex LH20, on reversed phase silica gel (such as Cig bonded, aminopropyl bonded, or cyanopropyl bonded), or even on ion-exchange resins. HPLC purification using acidic (TFA) or buffered eluents have frequently been employed. 

In most proteins the proportion of each of the different a.a. residues, calculated as a percent of the total number of residues, ranges from 0 to about 30%. In extreme cases it may even reach 50%. Cereal proteins are generally very poor in Lys. Several major grains are deficient in Thr, Leu, Met, Val, and Trp. In most collagens there are no Cys and Trp residues, while the content of Gly, Pro, and Ala is 328, 118, and 104 residues/1000 residues, respectively. Paramyosin, abundant in the muscles of marine invertebrates, is rich in Glu (20-24%), Asp (12%), Arg (12%), and Lys (9%). The antifreeze fish serum glycoproteins contain several a.a. sequences of Thr-X2-Y-X7, where X is predominantly Ala and Y a polar residue. The antifreeze proteins of type I usually contain more than 60 mol% of Ala. Thr and Y, and in various antifreeze... 

Phospholipid contents are very similar (about 1 to 2% dry matter) in microbial, plant, and animal tissues. If the content of neutral lipids is low, phospholipids may account for 20 to 40% of lipid extracts (e.g., in marine invertebrates). In egg yolk, 23% of the total lipids are phospholipids and other polar lipids (Kuksis, 1985). On the contfary, in adipose tissue or in oilseeds, the content of phospholipids is between 1 and 3% of total lipids. In oilseeds rich in oil (such as in rapeseed), it is lower than in oilseed with lower oil content (such as soybeans) when the results are expressed in % oil content, but much the same if the content is expressed in terms of total dry matter of the oilseed. Phospholipids are mainly extracted by nonpolar solvents, together with other lipids, and are obtained in the crude oil. However, in the original material, phospholipids are primarily bound to proteins (e.g., in membranes) or may be bound to other tissue components for example, phospholipids interact with chlorophyll pigments, where they may form complexes between the magnesium ion of the chlorophyll molecule and the phospho group of the phospholipids. 

Two more factors contributing to the persistence of xenobiotics in polychaetes, molluscs, crustaceans and echinoderms, and presumably other marine invertebrates, are the formation of macromolecular adducts and the slow release of free metabolites. The incorporation of PAH into more stable compartments , possibly as a result of cytochrome P-450-mediated adduct formation, is particularly evident in molluscs (see Fig. 3). The metabolites of many xenobiotics are lost more slowly than the parent compound, resulting in a build-up in the tissues during both exposure and subsequent depuration periods. The primary function of metabolism, therefore, appears to be detoxication, by preventing the formation of specific reactive metabolites and, probably more importantly, the non-specific toxic action of lipophilic xenobiotics caused by their penetration of membrane systems. Loss of metabolites down a concentration gradient occurs, reducing body burden of the xenobiotic, but is obviously limited by the absence or ineffectiveness of specific transport and excretory systems for the polar metabolites. 

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