It is important to emphasize that the sea cucumber H. glaberrima has, thus,
become the holothurian with the largest number of genes described, and a reference for the genomic analysis of other members of its class.
Immune System
One of the research areas that has benefited indirectly from these regeneration
studies is the field of echinoderm immunology. The reason is that regeneration
follows the loss of tissues and this loss is usually associated with some traumatic
event causing exposure of the animal’s internal environment to the outside media.
Thus, the immune system is activated to deal with the possible invasion of
pathogens. For example, in the case of evisceration, the cloaca ruptures and as the
internal viscera are ejected, the coelomic cavity is exposed to the sea water.
The outcome of these events is that activation of the regenerative process could
be occurring along with activation of the immune system. Cells and genes that
might be associated with regeneration might in reality be involved in the immune
response or vice versa. Alternatively the possibility exists that the two events are
somehow coupled and that immune associated cells and molecules are also participating in the regenerative process.
Lipopolysaccharide (LPS), a component of the bacterial cell wall, has been
used to study if genes associated with regenerative processes are also associated
with immune activation. LPS causes a coelomocyte-mediated immune response in
H. glaberrima, inducing an approximately threefold increase in coelomocyte
phagocytic activity (Santiago-Cardona et al. 2003). A large number of immunerelated genes were identified from the EST database (Ramírez-Gómez et al. 2008)
and many of these were shown to be associated with LPS-induced activation
(Ramírez-Gómez et al. 2009).
These studies have prompted a further in depth study into how different
pathogens might be able to activate different components of the immune system, in
particular different sub-populations of coelomocytes (Ramírez-Gómez et al. 2010).
In summary, H. glaberrima has also served to study the immune responses in
holothurians and has provided important information on fundamental aspects of
the cellular and molecular immune response (Ramírez-Gómez and García-Arrarás
2010).
Molecular Evolution
Echinoderms are a key group evolutionary group of animals. They are invertebrate
deuterostomes closely related to chordates. As such, they can provide key information on the evolution of genes and their associated roles. Experiments with
H. glaberrima have already documented the evolution of particular genes. Some of
these data can be found associated with genomic studies (Rojas-Cartagena et al.
2007; Ramírez-Gómez et al. 2008; Ortiz-Pineda et al. 2009). Other genes have
14 Review of Echinoderm Research in Puerto Rico
453
become the holothurian with the largest number of genes described, and a reference for the genomic analysis of other members of its class.
Immune System
One of the research areas that has benefited indirectly from these regeneration
studies is the field of echinoderm immunology. The reason is that regeneration
follows the loss of tissues and this loss is usually associated with some traumatic
event causing exposure of the animal’s internal environment to the outside media.
Thus, the immune system is activated to deal with the possible invasion of
pathogens. For example, in the case of evisceration, the cloaca ruptures and as the
internal viscera are ejected, the coelomic cavity is exposed to the sea water.
The outcome of these events is that activation of the regenerative process could
be occurring along with activation of the immune system. Cells and genes that
might be associated with regeneration might in reality be involved in the immune
response or vice versa. Alternatively the possibility exists that the two events are
somehow coupled and that immune associated cells and molecules are also participating in the regenerative process.
Lipopolysaccharide (LPS), a component of the bacterial cell wall, has been
used to study if genes associated with regenerative processes are also associated
with immune activation. LPS causes a coelomocyte-mediated immune response in
H. glaberrima, inducing an approximately threefold increase in coelomocyte
phagocytic activity (Santiago-Cardona et al. 2003). A large number of immunerelated genes were identified from the EST database (Ramírez-Gómez et al. 2008)
and many of these were shown to be associated with LPS-induced activation
(Ramírez-Gómez et al. 2009).
These studies have prompted a further in depth study into how different
pathogens might be able to activate different components of the immune system, in
particular different sub-populations of coelomocytes (Ramírez-Gómez et al. 2010).
In summary, H. glaberrima has also served to study the immune responses in
holothurians and has provided important information on fundamental aspects of
the cellular and molecular immune response (Ramírez-Gómez and García-Arrarás
2010).
Molecular Evolution
Echinoderms are a key group evolutionary group of animals. They are invertebrate
deuterostomes closely related to chordates. As such, they can provide key information on the evolution of genes and their associated roles. Experiments with
H. glaberrima have already documented the evolution of particular genes. Some of
these data can be found associated with genomic studies (Rojas-Cartagena et al.
2007; Ramírez-Gómez et al. 2008; Ortiz-Pineda et al. 2009). Other genes have
14 Review of Echinoderm Research in Puerto Rico
453