Spatiotemporal distributions of intestinal helminths in female lesser scaup Aythya affinis during spring migration from the upper Midwest, USA.

We examined the associations between intestinal helminth infracommunity structure and infection parameters and the age, size, and year and region of collection of 130 female lesser scaup (Aythya affinis) during their 2014-2015 spring migrations through the upper Midwest, USA. We identified a total of 647,174 individual helminths from 40 taxa, including 20 trematodes, 14 cestodes, 4 nematodes and 2 acanthocephalans parasitizing lesser scaup within the study area. Lesser scaup were each infected with 2-23 helminth taxa. One digenean, Plenosoma minimum, is reported for the first time in lesser scaup and in the Midwest. Mean trematode abundance and total helminth abundance was significantly less in 2015 than 2014, and we suspect that colder weather late in 2015 impacted the intermediate host fauna and caused the observed differences. Brillouin's species diversity of helminths was greatest in the northernmost region of the study area, which coincides with the range of a non-indigenous snail that indirectly causes annual mortality events of lesser scaup. While host age and size were not determined to be influential factors of helminth infracommunity structure, non-parametric ordination and permutational analysis of co-variance revealed that year and region of collection explained differences in helminth infracommunities. Our results suggest that spatiotemporal variations play an important role in the structure of intestinal helminth infracommunities found in migrating lesser scaup hosts, and may therefore impact host ability to build endogenous reserves at certain stopover locations in the Midwest.

Interspecific and Spatial Comparisons of Perfluorinated Compounds in Bighead and Silver Carp in the Illinois River, Illinois, USA.

We examined perfluoroalkyl compounds (PFC) in bighead (BHCP; Hypophthalmichthys nobilis) and silver (SVCP; H. molitrix) carp from the Illinois River, Illinois, USA. Summed PFC concentrations in whole fish did not differ by species or river reach. Perfluorooctanesulfonate (PFOS) concentrations were much greater in whole fish (16.4 ng/g) than in fillets (3.4 ng/g). PFOS concentrations represented 35%-51% of total measured PFC concentrations in whole fish, and in fillets were weakly associated with carcass mass (R2=0.17, p=0.01) and % carcass lipid (R2=0.16, p=0.01). No such relationship was observed in whole fish. The relationship between concentrations of individual PFC congeners in whole fish and carcass mass or % lipid content varied by species. Our study demonstrated that filter-feeders such as BHCP and SVCP can accumulate measureable concentrations of PFC and these results are important for understanding the fate of these compounds in large river systems.

Contaminant concentrations in Asian carps, invasive species in the Mississippi and Illinois Rivers.

Populations of invasive fishes quickly reach extremely high biomass. Before control methods can be applied, however, an understanding of the contaminant loads of these invaders carry is needed. We investigated differences in concentrations of selected elements in two invasive carp species as a function of sampling site, fish species, length and trophic differences using stable isotopes (delta (15)N, delta (13)C). Fish were collected from three different sites, the Illinois River near Havana, Illinois, and two sites in the Mississippi River, upstream and downstream of the Illinois River confluence. Five bighead carp (Hypophthalmichthys nobilis) and five silver carp (Hypophthalmichthys molitrix) from each site were collected for muscle tissue analyses. Freshwater mussels (Amblema plicata) previously collected in the same areas were used as an isotopic baseline to standardize fish results among sites. Total fish length, trophic position, and corrected (13)C, were significantly related to concentrations of metals in muscle. Fish length explained the most variation in metal concentrations, with most of that variation related to mercury levels. This result was not unexpected because larger fish are older, giving them a higher probability of exposure and accumulation of contaminants. There was a significant difference in stable isotope profiles between the two species. Bighead carp occupied a higher trophic position and had higher levels of corrected (13)C than silver carp. Additionally bighead carp had significantly lower concentrations of arsenic and selenium than silver carp. Stable isotope ratios of nitrogen in Asian carp were at levels that are more commonly associated with higher-level predators, or from organisms in areas containing high loads of wastewater effluent.

Coaccumulation of cadmium and zinc in tissues of sentinel mallards (Anas platyrhynchos) using a former dredge-disposal impoundment.

Six- to eight-month-old female farm-raised mallards (Anas platyrhynchos) were used to examine the accumulation of and association among cadmium (Cd), zinc (Zn), and copper (Cu) from an impoundment constructed to contain sediments dredged from a lake contaminated by a zinc smelter. Cd was not detectable in the livers t of farm-raised mallards (day 0), although sentinel mallards accumulated hepatic Cd in the first 7 days after release. By day 14, mean concentrations of Cd in kidneys (= 2.82 mg/kg wet weight) had increased 3.4-fold. The mean pancreatic Cd concentration increased 59% between days 7 and 14. Renal Zn increased nominally, whereas pancreatic Zn increased 63% in sentinel ducks after release. Hepatic Zn increased significantly in the first week of release. Renal and pancreatic Cu concentrations did not change significantly, whereas concentrations of Cu in livers of ducks increased 50% in the 7 days after release before decreasing by nearly the same degree. Concentrations of Cd and Zn were correlated in livers of sentinel mallards on days 7 and 14. Cd and Cu were not correlated in the tissues of any cohort. Cu and Zn were correlated in the livers of farm-raised mallards, in the pancreases of sentinel mallards at day 7, and in the kidneys of the ducks in all three treatments. The relationship between Cd and Zn in tissues of ducks in our study was complicated by simultaneous exposure to increased and heterogeneous concentrations of Cd and Zn, both of which can induce metallothionein and compete for this and other ligands.

Use of a simulated gizzard to measure bioavailability of metals and other elements to waterfowl.

We used a simulated gizzard environment to examine the bioavailability of barium, cadmium, copper, lead and zinc to wild and sentinel mallards (Anas platyrhynchos) using a seasonally-flooded wetland. This impoundment was originally constructed as a containment area for dredged sediments which were contaminated through previous smelting operations. Extraction of elements from gizzard contents indicated that sentinel mallards experienced greater exposure to contaminants than their wild counterparts. Concentrations of the selected elements extracted from ingesta were lower than in seeds and sediments from the study site. Notable exceptions were barium and lead, which were not detected in seeds of some plant species, though they were present in the ingesta of one or more treatment groups. This technique may provide a more realistic means of estimating bioavailability and exposure than methods which measure total concentrations of elements in dietary components. The use of sentinel mallards may result in inflated estimates of risk to wild ducks using seasonally-available wetlands.

Influence of diet on the hematology and serum biochemistry of zinc-intoxicated mallards.

Changes in hematological and serum biochemistry parameters in female zinc (Zn)-dosed farm-raised mallards (Anas platyrhynchos) fed four different diets were examined. Sixty ducks received an average dose of 0.97 g of Zn in the form of eight, 3.30-mm diameter shot pellets containing 98% Zn and 2% tin, and another 60 ducks were sham-dosed as controls. Fifteen ducks from each of the two dosing groups were assigned to one of four dietary treatments: corn only, corn with soil, commercial duck ration only, or commercial duck ration with soil. Shot-pellet dissolution rates ranged from 7 mg/Zn/day to 27 mg/Zn/day. Regardless of diet, the Zn dose resulted in mortality; incoordination; paralysis and anorexia; decreased body, liver, pancreas, gonad, and gizzard weight; increased kidney weight; and macroscopic lesions. Zn-dosed ducks had a lower mean erythrocyte packed cell volume (PCV), higher mean reticulocyte count, and a greater number of individuals with immature and/or abnormal erythrocytes, than did control mallards. Mean total leucocyte counts were higher in Zn-dosed ducks than in controls. Zn-dosed ducks that had soil available had higher leucocyte counts than those without soil. Zn-dosed ducks were characterized by a marked heterophilia and relative lymphopenia. In Zn-dosed ducks, the mean lymphocyte count was highest in those provided a commercial duck ration, and lowest in those fed corn. In control ducks, the mean lymphocyte count was highest in ducks fed corn, and lowest in those provided soil along with a commercial duck ration. Zn-dosed mallards had higher serum aspartate aminotransferase and amylase levels, and lower alkaline phosphatase activities than control ducks. Serum phosphorus and uric acid concentrations were higher, and calcium, glucose, and total protein levels lower, in Zn-dosed ducks than in control ducks. Diet did affect serum calcium, phosphorus, total protein, and uric acid concentrations. Differences in erythrocyte and leucocyte parameters, serum enzyme activities, and metabolite concentrations were associated with dose and diet effects. Diets high in protein and other organic matter and calcium and phosphorus did not prevent or substantially alleviate Zn toxicosis in farm-raised mallard ducks.

Organochlorine pesticide and polychlorinated biphenyl residues in Canada geese (Branta canadensis) from Chicago, Illinois.

Breast muscle samples, with or without overlying adipose tissue and skin, were obtained from Canada geese collected in northeastern illinois while undergoing feather molt. Specimens were evaluated for contaminant concentrations to determine if they would be acceptable as human food provided through government-subsidized programs. Samples were baked, allowing fat to drip free, and assayed for persistent organochlorine pesticides and polychlorinated biphenyls. Residues of heptachlor epoxide, dieldrin, DDE and PCBs (as Arochlor 1248) were detected. The specimens contained relatively low concentrations of contaminants, such that US Department of Agriculture residue limits for meat were exceeded in only 1 sample. Baking of breast muscle without the overlying skin and adipose tissue resulted in reductions in concentrations of detectable compounds. Fewer samples baked with the skin attached had detectable concentrations of heptachlor epoxide, dieldrin and PCB then samples cooked without skin; however, the converse was true for DDE. Periodic monitoring for environmental contaminants such as PCBs, exclusion of geese from localities where samples have contaminants such as PCBs, exclusion of geese from localities where samples have contaminants at concentrations that exceed recommended dietary limits, the use of processing and/or cooking methods which remove large amounts of lipid, and advisories that provide information on known health risks are recommended if wild resident Canada geese from the Chicago area are provided as food for underprivileged humans.

Post-transcriptional regulation of the Na+/Ca2+ exchanger in aging rat heart.

Altered calcium homeostasis in the senescent heart appears to be the result, at least in part, of decreased Na+/Ca2+ exchange activity. To further investigate the basis of the decrease in Na+/Ca2+ exchange activity, Na+/Ca2+ exchanger gene expression in the heart was compared in 3 and 24 month old male Fischer 344 rats. Sarcolemmal vesicles prepared from left ventricle and septum showed reduced Na(+)-dependent Ca2+ uptake in 24 month old animals when compared to 3 month old animals (0.156 +/- 0.005 and 0.135 +/- 0.008 nmol Ca2+/mg/10 s; mean +/- S.E. for 3 month and 24 month old animals, respectively). Western analysis showed immunodetectable Na+/Ca2+ exchanger protein levels were decreased by 19% in 24 month old animals when compared to 3 month old animals. Poly(A+) RNA was purified from left and right ventricle and left and right atria and subjected to Northern analysis using digoxin labeled cDNA probes for the Na+/Ca2+ exchanger and actin. The Na+/Ca2+ exchanger probe labeled a 7 kb message in both ventricle and atria, while the actin probe labeled both beta-actin (2.2 kb) and alpha-actin (1.4 kb). The steady state level of expression of Na+/Ca2+ exchanger Poly(A+) RNA when normalized to beta-actin, was similar when ventricle and atria were compared. There were no observable differences in Na+/Ca2+ exchanger or alpha-actin Poly(A+) RNA steady state levels when comparing 3 and 24 month old animals. The results suggest that reduced Na+/Ca2+ exchange activity in the left ventricle of 24 month old animals was most likely the result of post-transcriptional modification of the protein that was detectable by Western analysis.

Studies of the mechanism underlying increased Na+/Ca2+ exchange activity in Alzheimer's disease brain.

The Na+/Ca2+ exchanger was characterized in plasma membrane vesicles derived from frozen human postmortem tissues. The frontal cortex, temporal cortex and cerebellum of control and Alzheimer's disease (AD) tissues were compared. Na+/Ca2+ exchange activity was defined as the change in vesicular Ca2+ content seen after Na+ loaded vesicles were diluted into choline buffer. The time course of changes in Ca2+ content after dilution was similar in all three regions of control brain. In AD brain, both frontal and temporal cortex vesicles showed elevated Ca2+ content, most evident as an increased peak Ca2+ content at 2 min. The AD cerebellar cortex time course was similar to control and did not show an elevated peak at 2 min. No differences were seen in the passive permeability to Ca2+ when comparing plasma membrane vesicles prepared from control and AD brain. Vesicles from the frontal and temporal cortex of AD brain showed increases in the Vmax of the initial velocity of Ca2+ uptake when compared to control brain, whereas, the cerebellum did not. There were no significant effects of AD on the Km for Ca2+ activation of the initial velocity. Ca2+ influx measured during the rise in vesicular Ca2+ content was elevated in vesicles from AD temporal cortex when compared to control. Two known inhibitors (exchange inhibitory peptide and dichlorobenzamil) of the cardiac Na+/Ca2+ exchanger inhibited the human brain exchanger equally well in control and AD vesicles. Increased Na+/Ca2+ exchange activity was not due to astrocytic gliosis.(ABSTRACT TRUNCATED AT 250 WORDS)