A sea change in our view of overturning in the subpolar North Atlantic.

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

Strategies for analyzing cardiac phenotypes in the zebrafish embryo.

The molecular mechanisms underlying cardiogenesis are of critical biomedical importance due to the high prevalence of cardiac birth defects. Over the past two decades, the zebrafish has served as a powerful model organism for investigating heart development, facilitated by its powerful combination of optical access to the embryonic heart and plentiful opportunities for genetic analysis. Work in zebrafish has identified numerous factors that are required for various aspects of heart formation, including the specification and differentiation of cardiac progenitor cells, the morphogenesis of the heart tube, cardiac chambers, and atrioventricular canal, and the establishment of proper cardiac function. However, our current roster of regulators of cardiogenesis is by no means complete. It is therefore valuable for ongoing studies to continue pursuit of additional genes and pathways that control the size, shape, and function of the zebrafish heart. An extensive arsenal of techniques is available to distinguish whether particular mutations, morpholinos, or small molecules disrupt specific processes during heart development. In this chapter, we provide a guide to the experimental strategies that are especially effective for the characterization of cardiac phenotypes in the zebrafish embryo.

Experimental transmission of Cystoisospora felis-like coccidium from bobcat (Lynx rufus) to the domestic cat (Felis catus).

Cystoisospora felis is an ubiquitous coccidian of cats. The domestic cat (Felis catus) is its definitive host and several mammalian and avian species are its optional intermediate/transport hosts. Nothing is known if it is transmissible to wild felids. In the present study C. felis-like oocysts were found in two naturally infected bobcats (Lynx rufus) from Pennsylvania. To study transmission of C. felis-like parasite from bobcats to domestic cats, sporulated oocysts of C. felis-like from one bobcat were orally inoculated into interferon gamma gene knockout (KO) mice, and 56 days later tissues of KO mice were fed to two coccidian-free cats; two littermate cats were uninoculated controls. The inoculated cats and controls were euthanized five and seven days later, and their small intestines were studied histologically. One inoculated cat excreted C. felis-like oocysts seven days post inoculation (p.i.) and was immediately euthanized. Mature schizonts, mature male and female gamonts, and unsporulated oocysts were found in the lamina propria of small intestine; these stages were morphologically similar to C. felis of domestic cats. No parasites were seen in histological sections of small intestines of the remaining three cats. The experiment was terminated at seven days p.i. (minimum prepatent period for C. felis) to minimize spread of this highly infectious parasite to other cats. Although oocysts of the parasite in bobcats were morphologically similar to C. felis of domestic cats, the endogenous stages differed in their location of development. The bobcat derived parasite was located in the lamina propria of ileum whereas all endogenous stages of C. felis of domestic cats are always located in enterocytes of intestinal epithelium. Characterization of DNA isolated from C. felis-like oocysts from the donor bobcat revealed that sequences of the ITS1 region was only 87% similar to the ITS1 region of C. felis from domestic cats. These results indicate that the parasite in bobcat is likely different than C. felis of cats.

Prevalence of IgG Antibodies to Toxoplasma gondii in Veterinary and Undergraduate Students at Virginia Tech, Blacksburg, Virginia.

Toxoplasma gondii is a globally distributed parasitic protozoan that infects humans and other warm-blooded vertebrates. Felids are the only definitive host for T. gondii, and they excrete oocysts in their faeces. The national prevalence in humans is declining in the United States. This zoonotic organism is of particular interest due to its importance in pregnant women, in individuals with altered immune systems, and in reactivated ocular infections. Exposure to the parasite in humans is usually associated with consumption of raw or undercooked meat or by accidental ingestion of oocysts. It was hypothesized that veterinary students would have a greater chance at exposure to the parasite than an average population of undergraduate students due to increased contact with cats who are infected. A commercially available ELISA was used to examine serum samples from 336 students (252 veterinary students and 84 undergraduate students) at Virginia Polytechnic Institute and State University and the Virginia-Maryland Regional College of Veterinary Medicine for serum IgG antibodies to T. gondii antigen. The prevalence of T. gondii in these subjects was 5.6% in veterinary school students (n = 252) and 2.4% in undergraduates (n = 84). There was no significant difference (P > 0.05) in the prevalence of T. gondii antibodies in veterinary versus undergraduate students. The overall prevalence of 4.8% in all students in this study reflects the continuing decline of antibodies to T. gondii in humans in the United States.