Invertebrates and Other Lower Animals

Marine Invertebrate and Other Lower Animal Biosynthetic Products... 

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. 

In lower vertebrates, as in mammals, Dmrtl mRNA was also expressed in adult ovarian tissue of several fish species (Table 2). Moreover, in addition to the testis-specific tDmrtl, the other DM domain gene (tDMO) was isolated from one teleost fish, the tilapia (Guan et al., 2000). tDMO (tilapia DM domain gene in Ovary), the expression of which is limited to the ovary in adult animals, is the first-described female-sp>ecific DM domain gene in vertebrates. In contrast to the alternatively sphced male and female invertebrate doublesex (Burtis Baker, 1989), tDmrtl and tDMO cDNAs ap>p)ear to be encoded by two different genes that share little homology outside the DM domain... 

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