Studies in Sea Urchins

It is striking that a similar pattern of HI variant expression during early development has been maintained in the whole subkingdom of Deuterostomes, as illustrated by studies in sea urchin and X. laevis. This possibly dates back to an earlier stage before the separation of Deuterostomes and Mollusca (see the... 

SAPs have been and continue to be actively studied in sea urchins, but they have also been found in starfish (Noshigaki et al, 1996) and in the egg masses of the cuttlefish Sepia officinalis (Zatylny et al, 2002). Starfish and cuttlefish SAPs have been termed AsteroSAPs and SepSAPs, respectively. The presence of these peptides, however, is more general and reviews have been published on marine invertebrates and their attractins and other kinds of peptide pheromones (Susswein and Nagle, 2004) for crustaceans, see Rittschof and Cohen (2004). Research on these peptides and their synthetic analogs... 

Interestingly, prolonged duration of the first embryonic M phase is also observed in other mammalian and non-mammalian embryos. It was found in rabbit embryos (X. Yang M. Deng, personal communication) and in sea urchin embryos (J. Z. Kubiak P. Cormier, unpublished observation). Further studies will show whether it is a rule during animal development. 

As in the case of the gangliosides in vertebrates, the sialoglycolipids in sea urchins are cell-surface antigens. A study of antigenic specificity for two disialoglycolipids (from the eggs of S. intermedius) whose structures differ in only one respect, that a sulfate group is present on the sialic acid... 

Taste components of a number of sea food products have been examined for each sea food product has its individual characteristic taste. In studies on the free amino acids analysis (Table 9), it was shown that the major amino acid is His in red meat of fish, Gly and Pro in cuttlefish, Gly and Arg in prawns, and Tau and Arg in abalone ( ). The major amino acids in sea urchin are Gly, Ala and Leu (50). However, the components contributing to their individual characteristic tastes were not elucidated because the relationship between the taste components and the taste was not thoroughly correlated and Investigated in most of these studies. 

Induction of the acrosome reaction is a key event that occurs in sea urchins, starfish, ascidians and mammals. However, it is not clear that in the amphibian Xenopus sperm undergo the same type of acrosome reaction, because thus far it has not been possible to detect a morphologically identifiable acrosome vesicle in these sperm. The acrosome reaction in echinoderms and in mammals has been well studied. During the acrosome reaction the acrosomal vesicle fuses with the plasma membrane and the acrosomal components are externalized. Several proteolytic activities thought to be involved in penetration through the extracellular matrix of the egg are deteeted in the acrosomal contents. In addition, exposure of egg coat binding molecules on the surface of the sperm occurs (see below). 

The developmental expression of polySia chain synthesis in sea urchin PSGPs during embryogenesis seems likely to be an excellent experimental system to elucidate what regulates poly sialylation. Because the sea urchin embryo is a developmental system composed of three cell types in which the cell fate and tissue rearrangements are extensively understood (Foltz and Lennarz, 1993), this model system may also be ideal for studying the functional role of polySia chains. 

Tsushima, M. and Matsuno, T. (1990) Comparative biochemical studies of carotenoids in sea urchins I. Comp. Biochem. Physiol. 96B, 801-810. 

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