The Comet Assay, a Sensitive Biomarker of Water Quality Improvement Following Adoption of Beneficial Agricultural Practices?

Numerous actions have been undertaken by farmers to attenuate the impact of agricultural activities on aquatic ecosystems. The identification of biomarkers that respond quickly to water quality improvement could facilitate the assessment of adopted alternative practices and help maintain mobilization among stakeholders. We evaluated the potential of the comet assay, a biomarker of genotoxic effects, using a freshwater mussel, Elliptio complanata, as a model animal.

Mitochondrial thermo-sensitivity in invasive and native freshwater mussels.

Climate change is impacting many, if not all, forms of life. Increases in extreme temperature fluctuations and average temperatures can cause stress, particularly in aquatic sessile ectotherms such as freshwater mussels. However, some species seem to thrive more than others in face of temperature-related stressors.

Cumulative effects of cadmium and natural stressors (temperature and parasite infection) on molecular and biochemical responses of juvenile rainbow trout.

The simultaneous presence of natural and anthropogenic stressors in aquatic ecosystems can challenge the identification of factors causing decline in fish populations. These stressors include chemical mixtures and natural abiotic and biotic factors such as water temperature and parasitism. Effects of cumulative stressors may vary from antagonism to synergism at the organismal or population levels and may not be predicted from exposure to individual stressors.

Stress-related gene transcription in fish exposed to parasitic larvae of two freshwater mussels with divergent infection strategies.

Freshwater unionoid mussels have a unique life cycle involving a temporary parasitic phase. Their larvae (glochidia) attach to the gills or fins of fish hosts where they remain encysted until metamorphosis into free-living juveniles. The physiological response of fish during the critical period of glochidial attachment is not well understood, but recent work suggests that glochidia retention and survival is enhanced in stressed and cortisol-injected hosts.

The effect of cryopreservation on mitochondrial function in freshwater mussel tissue samples (Bivalvia: Unionida).

In non-thermoregulating and sessile organisms, such as the imperiled freshwater mussels (Bivalvia: Unionida), thermal sensitivity of mitochondria is a key factor for survival to global warming. Given the protected status of many unionids, non-destructive biopsies and subsequent cryopreservation are advisable procedures for further investigation of their mitochondrial function. To address whether long-term cryopreservation affects mitochondria in freshwater mussels, the mitochondrial respiration in permeabilized somatic cells of Elliptio complanata has been fully characterized through high-resolution respirometry.

Cumulative effects of municipal effluent and parasite infection in yellow perch: A field study using high-throughput RNA-sequencing.

Multiple metabolic, immune and reproductive effects have been reported in fish residing in effluent-impacted sites. Natural stressors such as parasites also have been shown to impact the responses of organisms to chronic exposure to municipal effluent in the St. Lawrence River (Quebec, Canada).

Enigmatic decline of a common fish parasite ( spp.) in the St. Lawrence River: Evidence for a dilution effect induced by the invasive round goby.

As they integrate into recipient food webs, invasive exotic species may influence the population dynamics of native parasites. Here we assess the potential impact of the Eurasian round goby () on the abundance of eyeflukes of the genus , which are common parasites in fishes of the St. Lawrence River (Canada).

Integrated spatial health assessment of yellow perch (Perca flavescens) populations from the St. Lawrence River, Quebec, Canada) part A: physiological parameters and pathogen assessment.

A multi-disciplinary approach was used to evaluate the health of yellow perch (Perca flavescens) in the St. Lawrence River (Quebec, Canada), which is experiencing a severe population decline in the downstream portion of the river. Physiological parameters, liver alterations, trace metal concentrations, parasite prevalence and abundance, stable isotope composition, and the presence/absence of the viral hemorragic septicemia virus (VHSV) were evaluated in perch collected at six sites along the river: Lake St.

Variation in Parasite Communities in Spottail Shiners (Notropis hudsonius) Linked with Precipitation.

The Richelieu River, Quebec, is a highly-regulated waterway subject to numerous anthropogenic influences from municipal effluents and agricultural activities. Parasite communities in 234 spottail shiners (Notropis hudsonius) were examined from 4 localities in late spring 2003 and 2004. Component species richness varied between 15 and 18 species in 2003 but declined to 9 to 13 in 2004, while total parasite abundance was consistently lower in 2003.

Correlation of parasites with growth of yellow perch.

The possible influence of parasites on the short-term and long-term growth and condition of yellow perch Perca flavescens was examined by investigating correlations between parasite abundance and specific growth variables. The following parasites were enumerated in age-1 yellow perch collected from Lake St. Pierre in June 2008: Apophallus brevis, Diplostomum spp.

Impact of municipal effluents and hydrological regime on myxozoan parasite communities of fish.

Increased productivity from sewage effluents can enhance species richness locally. Results from a study of spottail shiners (Notropis hudsonius) in 1999 showed that prevalence and the mean number of myxozoan parasite species per host were higher downstream of the wastewater outflow from the Island of Montreal than upstream in the St. Lawrence River, Quebec, Canada.

Gill and head kidney antioxidant processes and innate immune system responses of yellow perch (Perca flavescens) exposed to different contaminants in the St. Lawrence River, Canada.

Biomarkers of oxidative stress metabolism and the innate immune response were examined in gill and head kidney tissue of wild-caught yellow perch (Perca flavescens) collected from four sites ranging in type and degree of metal pollution in the St. Lawrence River, Quebec, Canada. Sites were ranked as follows: Ile Dorval View Article and Find Full Text PDF

Short-term seasonal changes in parasite community structure in northern leopard froglets (Rana pipiens) inhabiting agricultural wetlands.

Parasite community structure can change seasonally with shifts in host habitat and in diet. However, anthropogenic activity may influence the natural changes in transmission dynamics of different parasite species. Effects of seasonal and agricultural activity on the parasite communities of newly metamorphosed northern leopard frogs (Rana pipiens) were investigated in July and September 2001 in 5 wetlands, 3 of which were exposed to pesticide runoff from surrounding agriculture.

Joint effects of parasitism and pollution on oxidative stress biomarkers in yellow perch Perca flavescens.

Yellow perch Perca flavescens were collected from a contaminated site and a reference site in the St. Lawrence River, Quebec, Canada. Fish were assessed for oxidative stress (lipid peroxidation and reduced glutathione levels) and parasitism by the nematode Raphidascaris acus and metacercariae of the digenean Apophallus brevis.

Effects of agricultural pesticides on the immune system of Rana pipiens and on its resistance to parasitic infection.

In the past 30 years, many amphibian species have suffered population declines throughout the world. Mass mortality have been frequently reported, and in several instances, infectious diseases appear to be the cause of death. The role that contaminants could play in these die-offs through immunotoxic effects has been poorly investigated.