Copper exposures on the endangered delta smelt

ABSTRACT: The delta smelt (Hypomesus transpacificus) is an endangered pelagic fish species endemic to the Sacramento-San Joaquin estuary, California, and considered an indicator of ecosystem health. The experimental combination of molecular biomarkers with higher level condition indicators may allow for interpretation of responses in a functional context that can be used to predict detrimental outcomes caused by contaminant exposure. Copper is a contaminant of concern in Californian waterways that may affect the development and survival of this endangered species. We have developed and applied a delta smelt microarray in order to screen for probable candidate molecular biomarkers that may be used in monitoring programs. Functional classifications of microarray responses are presented along with quantitative Polymerase Chain Reaction (qPCR) assessments measuring effects upon neuromuscular, digestive and immune responses in delta smelt exposed to copper. Differences in sensitivity were measured between juvenile and larval delta smelt (LC¬5096h= 25.2 and 80.4 ?g/L Cu2+ respectively). Swimming velocity declined with higher exposure concentrations in a dose-dependent manner, though were not statistically significant to controls. Genes encoding for aspartoacylase (ASPA), hemopexin, alpha-actin and calcium regulation proteins were significantly affected by exposure and were functionally interpreted with measured swimming responses. Effects on digestion were measured by upregulation of chitinase and downregulation of amylase, whilst downregulation of tumor necrosis factor indicated a probable compromised immune system. We utilized 3 replicates for exposed samples and 3 replicates for controls, both of which were hybridized to a reference pool. Each replicate contained 4 pooled larval delta smelt. The Reference pool consisted of delta smelt samples from this experiment and a number of prior tests. No dye swaps were performed due to limited material. Supplementary file linked below reports candidate differentially expressed cDNAs. Data represented as filtered, normalized, Log-2 Alexa (547/555) ratios.

ORGANISM(S): Hypomesus transpacificus

SUBMITTER: Richard Connon 

PROVIDER: E-GEOD-23238 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress