Linoleic acid increases adhesion,chemotaxis, granule release,intracellular calcium mobilisation,MAPK phosphorylation and gene expression in bovine neutrophils

Neutrophils are critical to the innate immune response; therefore, the proper function of neutrophils is critical to avoid the development of certain diseases. Linoleic acid, a polyunsaturated long-chain fatty acid, is one of the most abundant long-chain fatty acids found in the plasma of cows after giving birth. In this study, we evaluated the effects of linoleic acid treatment on bovine neutrophil adhesion, chemotaxis, metalloproteinase (MMP)-9 release, CD11b expression, intracellular calcium mobilisation, mitogen-activating protein kinase (MAPK) phosphorylation and COX-2 and IL-8 expression. Bovine neutrophils isolated from healthy heifers were incubated with different concentrations of linoleic acid, and then neutrophil responses were evaluated. Our results show that the treatment of neutrophils with 100 μM linoleic acid increased their adhesion to the bovine endothelial cell line CPA47. The results of a transwell migration assay revealed that linoleic acid could also promote the chemotaxis of bovine neutrophils. Furthermore, linoleic acid treatment increased MMP-9 activity and CD11b cell surface expression in neutrophils. Fifty and 100 μM linoleic acid also increased intracellular calcium mobilisation in neutrophils loaded with Fluo-4 AM dye. Linoleic acid also rapidly (2–5 min) stimulated the phosphorylation of ERK1/2 and p38 MAPK as evaluated by immunoblot. Finally, COX-2 and IL-8 mRNA expression increased after 2 h of linoleic acid treatment. In conclusion, linoleic acid stimulates adhesion, chemotaxis, granule release and intracellular responses in bovine neutrophils.     

Histological evidence of accumulation of iron in postlarvae of red abalone,Haliotis rufescens

The effect of iron on abalone postlarvae (Haliotis rufescens) was investigated in a controlled‐culturing system. Three iron concentrations (0.15, 1.5 and 15 mg L^?1 of Fe) and a control (no iron added) were used to culture H. rufescens postlarvae while being fed the diatom Navicula inserta over 10 days. Results indicate that H. rufescens postlarvae accumulate iron granules in the stomach, digestive gland and mantle, but not in the gills or other tissues. The number and diameter of iron granules in tissues increased with increasing iron concentration in the culturing environment. The iron accumulation is assumed to have been acquired in the digestive system through the iron‐enriched diatom feed and in the mantle through subcutaneous iron transfer. The lack of iron granules in the gills suggests that iron is not absorbed through the respiratory system, as is the case for many filter feeding bivalves. Exposure to the highest iron concentration (15 mg L^?1) resulted in tissue abnormalities where granules accumulated, and may have significantly affected the health of H. rufescens postlarvae. These findings provide valuable information for the regulation of appropriate iron levels within aquaculture settings and highlights the importance of monitoring iron levels within abalone larval culturing environments.