Distinct distribution and responses of IgM, IgT1 and IgT2 B cells in common carp.

In teleosts, the immunoglobulin classes produced by B cells are IgM, IgD, and IgT/IgZ. IgT was initially described as an immunoglobulin specialized in mucosal responses; accumulating evidence, however, shows that it is also involved in systemic immune responses. Two types of IgT/IgZ (IgT1 and IgT2) were previously described in common carp, but their further characterization was hampered by the lack of specific tool.

Identification of a pharyngeal mucosal lymphoid organ in zebrafish and other teleosts: Tonsils in fish?

The constant exposure of the fish branchial cavity to aquatic pathogens causes local mucosal immune responses to be extremely important for their survival. Here, we used a marker for T lymphocytes/natural killer (NK) cells (ZAP70) and advanced imaging techniques to investigate the lymphoid architecture of the zebrafish branchial cavity. We identified a sub-pharyngeal lymphoid organ, which we tentatively named "Nemausean lymphoid organ" (NELO).

Symmetric expression of ohnologs encoding conserved antiviral responses in tetraploid common carp suggest absence of subgenome dominance after whole genome duplication.

Allopolyploids often experience subgenome dominance, with one subgenome showing higher levels of gene expression and greater gene retention. Here, we address the functionality of both subgenomes of allotetraploid common carp (Cyprinus carpio) by analysing a functional network of interferon-stimulated genes (ISGs) crucial in anti-viral immune defence. As an indicator of subgenome dominance we investigated retainment of a core set of ohnologous ISGs.

Repeated independent origins of the placenta reveal convergent and divergent organ evolution within a single fish family (Poeciliidae).

An outstanding question in biology is to what extent convergent evolution produces similar, but not necessarily identical, complex phenotypic solutions. The placenta is a complex organ that repeatedly evolved in the livebearing fish family Poeciliidae. Here, we apply comparative approaches to test whether evolution has produced similar or different placental phenotypes in the Poeciliidae and to what extent these phenotypes correlate with convergence at the molecular level.