bassianolide and Hemorrhage

In fish, the innate immune system is more important than the adaptive immune system because it responds quickly and nonspecifically to protect against pathogens. Thus, a variety of innate immune molecules have been found in fish. Recently, l-amino acid oxidases (LAOs) were discovered as a new member of the antibacterial protein from fish skin mucus and serum. In this study, we newly found an antibacterial LAO in red-spotted grouper (Epinephelus akaara) serum. It showed a broad range of substrate specificity with aromatic and hydrophobic amino acids. The grouper LAO gene had a low expression level in the kidney under normal conditions; however, it was significantly upregulated by blood loss 1 day after bleeding. In addition, the LAO activity in the serum recovered within 3 days in the same experiment. This quick recovery may indicate that the LAO is an essential innate immune molecule in the whole grouper body.

Topics: Animals; Anti-Bacterial Agents; Bass; Cloning, Molecular; Fish Proteins; Gene Expression Regulation; Head Kidney; Hemorrhage; Immunity, Innate; L-Amino Acid Oxidase; Substrate Specificity

Cultured juvenile white seabass Atractoscion nobilis (WSB) can suffer from intraocular emphysemas and exophthalmia in the hatchery environment. To identify the cause, two size-groups of WSB were exposed to five gas saturation levels, ranging from 98% to 122% total gas pressure (TGP), over a 96-h exposure period in 18 degrees C and 23 degrees C seawater. Histological examination revealed that the gross and subgross lesions associated with gas supersaturation included corneal and orbital emphysema, along with subretinal, optic nerve, and iridial hemorrhage. Corneal emphysema was the most prominent gross lesion, with the severity and prevalence increasing between size-groups and water temperatures as TGP increased. Following the same pattern was orbital emphysema, which affected more than 93% of the fish examined and caused hemorrhage in the subretinal space, around the optic nerve, in the iris, or a combination thereof. Iridial hemorrhage occurred in 91% of the fish examined and decreased significantly with fish size. The prevalence and severity of hemorrhage in the subretinal space increased significantly with TGP and fish size but not with temperature. Optic nerve hemorrhage was absent in small fish exposed at 18 degrees C but increased significantly with temperature and fish size. The reverse was true for the large fish.

Topics: Air Pressure; Animals; Bass; Body Size; Embolism, Air; Emphysema; Eye Diseases; Fish Diseases; Hemorrhage; Optic Nerve