Intranuclear crystalloids of Antarctic sea urchins as a biomarker for oil contamination

Because of human actions, biomarkers have become important to detect and mitigate pollution. This study showed that crystalloids can be a biomarker for analyses of low levels of water-soluble fractions of oil (WSF). Antarctic sea urchins (Sterechinus neumayeri) from regions free of pollution were exposed for 2, 5, 10 and 15 days at different levels of WSF (0.4, 0.8 and 1.2 ppm). No significant differences were observed in the phagocytic rates or the germicide capacity for the yeast Saccharomyces cerevisiae; however, there was a significant increase in the quantity of intranuclear iron crystalloids in phagocytic amoebocytes of urchins exposed to higher levels of WSF. This study characterizes histological alterations in crystalloids of S. neumayeri that could be used as a biomarker for oil contaminants, with a simple and inexpensive protocol.

Innate immune response in the sea urchin Echinometra lucunter (Echinodermata)

Echinometra lucunter, (Pinda) is a sea urchin encountered in the Brazilian coast and exposed to high and low temperatures related to low and high tides. Despite their great distribution and importance, few studies have been done on the biological function of their coelomocytes. Thus, Echinometra lucunter perivisceral coelomocytes were characterized under optical and transmission electron microscopy. Phagocytic amoebocytes in the perivisceral coelom were labelled by injecting ferritin, and ferritin labelled phagocytic amoebocytes were found in the peristomial connective tissue after injecting India ink into the tissue, indicating the amoebocytes ability to respond to an inflammatory stimulus. Results showed that the phagocytic amoebocytes were the main inflammatory cells found in the innate immune response of E lucunter. While other works have recorded these phenomena in sea urchins found in moderate and constant temperature, this study reports on these same phenomena in a tropical sea urchin under great variation of temperature, thus providing new data to inflammatory studies in invertebrate pathology. (C) 2007 Elsevier Inc. All rights reserved.

Cellular biomarkers to elucidate global warming effects on Antarctic sea urchin Sterechinus neumayeri

Global warming is a reality and its effects have been widely studied. However, the consequences for marine invertebrates remain poorly understood. Thus, the present study proposed to evaluate the effect of elevated temperature on the innate immune system of Antarctic sea urchin Sterechinus neumayeri. Sea urchins were collected nearby Brazilian Antarctic Station "Comandante Ferraz" and exposed to 0 (control), 2 and 4A degrees C for periods of 48 h, 2, 7 and 14 days. After the experimental periods, coelomic fluid was collected in order to perform the following analyses: coelomocytes differential counting, phagocytic response, adhesion and spreading coelomocytes assay, intranuclear iron crystalloid and ultra structural analysis of coelomocytes. The red sphere cell was considered a biomarker for heat stress, as they increased in acute stress. Besides that, a significant increase in phagocytic indexes was observed at 2A degrees C coinciding with a significant increase of intranuclear iron crystalloid at the same temperature and same time period. Furthermore, significant alterations in cell adhesion and spreading were observed in elevated temperatures. The ultra structural analysis of coelomocytes showed no significant difference across treatments. This was the first time that innate immune response alterations were observed in response to elevated temperature in a Polar echinoid.