Disorders of the respiratory system in pet and ornamental fish

Characterizing the origin of blood plasma proteins from organ tissues in rainbow trout (Oncorhynchus mykiss) using a comparative non-targeted proteomics approach

Protein expression patterns adapt to various cues to meet the needs of an organism. The dynamicity of an organism's proteome can therefore reveal information about an organism's health. Proteome databases contain limited information regarding organisms outside of medicinal biology. The UniProt human and mouse proteomes are extensively reviewed and ∼50 % of both proteomes include tissue specificity, while >99 % of the rainbow trout proteome lacks tissue specificity. This study aimed to expand knowledge on the rainbow trout proteome with a focus on understanding the origin of blood plasma proteins. Blood, brain, heart, liver, kidney, and gills were collected from adult rainbow trout, plasma and tissue proteins were analyzed using liquid chromatography tandem mass spectrometry. Over 10,000 proteins were identified across all groups. Our data indicated that the majority of the plasma proteome is shared amongst multiple tissue types, though 4-7 % of the plasma proteome is uniquely originated from each tissue (gill > heart > liver > kidney > brain).

Flow field around bubbles on formation of air embolism in small vessels

An air embolism is induced by intravascular bubbles that block the blood flow in vessels, which causes a high risk of pulmonary hypertension and myocardial and cerebral infarction. However, it is still unclear how a moving bubble is stopped in the blood flow to form an air embolism in small vessels. In this work, microfluidic experiments, in vivo and in vitro, are performed in small vessels, where bubbles are seen to deform and stop gradually in the flow. A clot is always found to originate at the tail of a moving bubble, which is attributed to the special flow field around the bubble. As the clot grows, it breaks the lubrication film between the bubble and the channel wall; thus, the friction force is increased to stop the bubble. This study illustrates the stopping process of elongated bubbles in small vessels and brings insight into the formation of air embolism.

Reactive oxygen species and other biochemical and morphological biomarkers in the gills and kidneys of the Neotropical freshwater fish, Prochilodus lineatus, exposed to titanium dioxide (TiO2) nanoparticles

This study investigated the action of titanium dioxide nanoparticles (TiO₂-NPs), on the gills and kidneys of Neotropical freshwater fish, Prochilodus lineatus, with emphasis on reactive oxygen species (ROS) production, antioxidant responses, and morphological changes. Fish were exposed to 1, 5, 10, and 50 mg L^-1 nominal TiO₂-NPs suspended into water for 2 or 14 days. In gills, ROS decreased and glutathione (GSH) increased after 2 days, while ROS and GSH increased and superoxide dismutase activity decreased after 14 days. In kidneys, GSH and lipoperoxidation increased after 2 days and catalase activity decreased after 14 days. Common histopathologies in gills were epithelium hyperplasia, cellular hypertrophy, proliferation of mitochondria-rich cells (MRC), and lamellar stasis; in kidneys, there were cellular and nuclear hypertrophy, focal tubule degeneration, necrosis, and melanomacrophage (MM) proliferation. Although environmentally unlikely, high-dose exposures clarified biological effects of TiO₂-NPs, such as ROS formation and MRC responses in the gills, which may impair ionic balance. It was also found that MM are likely responsible for eliminating NPs in the kidney. These findings will help to regulate TiO₂-NP disposal, but longer-term studies are still needed.

Characterization of the histologic appearance of normal gill tissue using special staining techniques

Anatomic pathologists are familiar with stains used in light microscopy to identify cells, storage products, tissue deposits, and pathogens. Assessment of the surrounding tissue with special stains may reveal aspects of interest for the tissue or the species. We illustrate the expected staining characteristics of normal rainbow trout gill tissue with routine hematoxylin and eosin and 18 other histochemical stains.