Bidirectional sex change induced by sex steroid implantation in the hermaphrodite fish, Pseudolabrus sieboldi.

Sex steroids have been suggested to be involved in gonadal sex change in hermaphrodite fish. Aromatase, the enzyme that catalyzes the conversion of androgens into estrogens, is a principal enzyme regulating gonadal sex. However, the detailed functions of each steroid hormone remain to be evaluated.

Morphological responses of mitochondria-rich cells to hypersaline environment in the Australian mudskipper, Periophthalmus minutus.

A population of the Australian mudskipper, Periophthalmus minutus, was found to inhabit mudflat that remained uncovered by tide for more than 20 days in some neap tides. During these prolonged emersion periods, P. minutus retreated into burrows containing little water, with a highest recorded salinity of 84 ± 7.

Ontogenetic phase shifts in metabolism: links to development and anti-predator adaptation.

The allometric relationships between resting metabolism (VO(2)) and body mass (M), VO(2) = a(i)M(b), are considered a fundamental law of nature. A distinction though needs to be made between the ontogeny (within a species) and phylogeny (among species) of metabolism. However, the nature and significance of the intraspecific allometry (ontogeny of metabolism) have not been established in fishes.

Molecular cloning and expression analysis of a GnRH-like dodecapeptide in the swordtip squid, Loligo edulis.

In vertebrates, gonadotropin-releasing hormone (GnRH), which is synthesized in the brain, is a key peptide involved in gonadal maturation regulated by the brain-pituitary-gonadal axis. GnRH isoforms and their primary structures have recently been determined in two species of non-chordates, the octopus (Octopus vulgaris) and sea hare (Aplysia californica), which are mollusks. Octopus and sea hare GnRHs are dodecapeptides that contain the structural core of chordate GnRH; however, chordate GnRHs, including tunicate GnRH, are decapeptides.

Mudskippers brood their eggs in air but submerge them for hatching.

Intertidal mudflats are highly productive ecosystems that impose severe environmental challenges on their occupants due to tidal oscillations and extreme shifts in habitat conditions. Reproduction on mudflats requires protection of developing eggs from thermal and salinity extremes, O(2) shortage, dislodgement by currents, siltation and predation. Mudskippers are air-breathing, amphibious fishes, and one of few vertebrates that reside on mudflats.