Limited genetic variation and structure in softshell clams (Mya arenaria) across their native and introduced range

Author Posting. © Springer, 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Conservation Genetics 10 (2009): 803-814, doi:10.1007/s10592-008-9641-y.To offset declines in commercial landings of the softshell clam, Mya arenaria, resource managers are engaged in extensive stocking of seed clams throughout its range in the northwest Atlantic. Because a mixture of native and introduced stocks can disrupt locally adapted genotypes, we investigated genetic structure in M. arenaria populations across its current distribution to test for patterns of regional differentiation. We sequenced mitochondrial cytochrome oxidase I (COI) for a total of 212 individuals from 12 sites in the northwest Atlantic (NW Atlantic), as well as two introduced sites, the northeast Pacific (NE Pacific) and the North Sea and Europe (NS Europe). Populations exhibited extremely low genetic variation, with one haplotype dominating (65-100%) at all sites sampled. Despite being introduced in the last 150-400 years, both NE Pacific and NS Europe populations had higher diversity measures than those in the NW Atlantic and both contained private haplotypes at frequencies of 10% to 27% consistent with their geographic isolation. While significant genetic structure (FST = 0.159, p<0.001) was observed between NW Atlantic and NS Europe, there was no evidence for genetic structure across the pronounced environmental clines of the NW Atlantic. Reduced genetic diversity in mtDNA combined with previous studies reporting reduced genetic diversity in nuclear markers strongly suggests a recent population expansion in the NW Atlantic, a pattern that may result from the retreat of ice sheets during Pleistocene glacial periods. Lack of genetic diversity and regional genetic differentiation suggests that present management strategies for the commercially important softshell clam are unlikely to have a significant impact on the regional distribution of genetic variation, although the possibility of disrupting locally adapted stocks cannot be excluded.This work was supported by NSF grants OCE-0326734 and OCE-0215905 to L. Mullineaux and OCE- 0349177 (Biological Oceanography) to PHB

Cilostazol Inhibits Accumulation of Triglyceride in Aorta and Platelet Aggregation in Cholesterol-Fed Rabbits

Cilostazol is clinically used for the treatment of ischemic symptoms in patients with chronic peripheral arterial obstruction and for the secondary prevention of brain infarction. Recently, it has been reported that cilostazol has preventive effects on atherogenesis and decreased serum triglyceride in rodent models. There are, however, few reports on the evaluation of cilostazol using atherosclerotic rabbits, which have similar lipid metabolism to humans, and are used for investigating the lipid content in aorta and platelet aggregation under conditions of hyperlipidemia. Therefore, we evaluated the effect of cilostazol on the atherosclerosis and platelet aggregation in rabbits fed a normal diet or a cholesterol-containing diet supplemented with or without cilostazol. We evaluated the effects of cilostazol on the atherogenesis by measuring serum and aortic lipid content, and the lesion area after a 10-week treatment and the effect on platelet aggregation after 1- and 10-week treatment. From the lipid analyses, cilostazol significantly reduced the total cholesterol, triglyceride and phospholipids in serum, and moreover, the triglyceride content in the atherosclerotic aorta. Cilostazol significantly reduced the intimal atherosclerotic area. Platelet aggregation was enhanced in cholesterol-fed rabbits. Cilostazol significantly inhibited the platelet aggregation in rabbits fed both a normal diet and a high cholesterol diet. Cilostazol showed anti-atherosclerotic and anti-platelet effects in cholesterol-fed rabbits possibly due to the improvement of lipid metabolism and the attenuation of platelet activation. The results suggest that cilostazol is useful for prevention and treatment of atherothrombotic diseases with the lipid abnormalities

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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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. Nineteen parasite taxa were found. Component community richness was consistently high at the pristine reference wetland, whereas the communities at a managed reference wetland remained depauperate. Infracommunity richness increased throughout the season, but more so in frogs resident in agricultural wetlands. Digeneans using frogs as intermediate hosts dominated the communities, although many species were much lower in abundance in September, suggesting mortality of heavily infected frogs. Mean abundance of Haematoloechus spp. was positively related to that of odonate naiads in the frog diet, which appeared to reflect differential second intermediate host availability between reference and agricultural wetlands. Although virtually absent from wetlands in July just after frog metamorphosis, monoxenous nematodes were more prevalent and abundant at agricultural wetlands as the season progressed. Our results suggest that agricultural activity may further facilitate the transmission of monoxenous nematodes as frogs become more terrestrial

Combined effects of agricultural activity and parasites on biomarkers in the bullfrog, Rana catasbeiana.

Agricultural contaminants can have devastating impacts on amphibian survival and development, particularly considering their sensitivity to environmental perturbation. However, it is commonly overlooked that amphibians are infected with various parasites that can influence the overall health of the animal when exposed to a stressful environment. We investigated the interaction of agriculture and parasitism on the health of bullfrogs (Rana catesbeiana) in the field. Nine physiological and immunological biomarkers were related to naturally acquired parasite infections, along a gradient of agricultural activity. Most health biomarkers were affected by agriculture, parasitism, or both. Although bullfrogs residing in agricultural areas were infected with fewer parasite species, reflecting environmentally compromised ecosystems, certain persistent parasites interacted with agricultural disturbance to alter the physiology and immune competence of bullfrogs. The consequences of the combination for animal health highlight the importance of parasitism in ecotoxicological studies. Consideration of parasitism is warranted when evaluating the influence of anthropogenic disturbance on amphibian declines and environmental health