Allelic Diversity of the Plasmodium falciparum Erythrocyte Membrane Protein 1 Entails Variant-Specific Red Cell Surface Epitopes

The clonally variant Plasmodium falciparum PfEMP1 adhesin is a virulence factor and a prime target of humoral immunity. It is encoded by a repertoire of functionally differentiated var genes, which display architectural diversity and allelic polymorphism. Their serological relationship is key to understanding the evolutionary constraints on this gene family and rational vaccine design. Here, we investigated the Palo Alto/VarO and IT4/R29 and 3D7/PF13_003 parasites lines. VarO and R29 form rosettes with uninfected erythrocytes, a phenotype associated with severe malaria. They express an allelic Cys2/group A NTS-DBL1α1 PfEMP1 domain implicated in rosetting, whose 3D7 ortholog is encoded by PF13_0003. Using these three recombinant NTS-DBL1α1 domains, we elicited antibodies in mice that were used to develop monovariant cultures by panning selection. The 3D7/PF13_0003 parasites formed rosettes, revealing a correlation between sequence identity and virulence phenotype. The antibodies cross-reacted with the allelic domains in ELISA but only minimally with the Cys4/group B/C PFL1955w NTS-DBL1α. By contrast, they were variant-specific in surface seroreactivity of the monovariant-infected red cells by FACS analysis and in rosette-disruption assays. Thus, while ELISA can differentiate serogroups, surface reactivity assays define the more restrictive serotypes. Irrespective of cumulated exposure to infection, antibodies acquired by humans living in a malaria-endemic area also displayed a variant-specific surface reactivity. Although seroprevalence exceeded 90% for each rosetting line, the kinetics of acquistion of surface-reactive antibodies differed in the younger age groups. These data indicate that humans acquire an antibody repertoire to non-overlapping serotypes within a serogroup, consistent with an antibody-driven diversification pressure at the population level. In addition, the data provide important information for vaccine design, as production of a vaccine targeting rosetting PfEMP1 adhesins will require engineering to induce variant-transcending responses or combining multiple serotypes to elicit a broad spectrum of immunity

Autumn Raptor Migration in Yellowstone National Park, 2011–2015

Raptors are wide-ranging, vagile avian predators whose populations can be difficult and costly to monitor on their breeding or winter range. However, monitoring raptors during their annual northbound or southbound migration is a cost-effective and efficient alternative to time-intensive, single-species breeding surveys. In 2010, we observed numerous Swainson’s Hawks (Buteo swainsoni) and Red-tailed Hawks (Buteo jamaicensis) migrating through the Hayden Valley in central Yellowstone National Park, prompting an investigation into raptor migration patterns in the park. Our objectives were to monitor annual autumn raptor migration in Hayden Valley from 2011 to 2015 and to determine the relative role of this undocumented migration site by comparing our observations to simultaneously collected migration data from three other sites in the Rocky Mountain Flyway. From 2011 to 2015, we observed 6441 raptors of 17 species across 170 d and 907 h of observation. Red-tailed Hawks, Swainson’s Hawks, and Golden Eagles (Aquila chrysaetos) accounted for 51% of the total individuals observed over five years. Overall counts from Hayden Valley were comparable to counts from the three migration sites in the Rocky Mountains, although abundance of individual species varied by site. Data from this study suggest that Hayden Valley may serve as a stopover site for migrating raptors and presents an opportunity for future research. By improving our understanding of where raptors migrate and the characteristics of stopover areas in the Rocky Mountains, land managers may develop effective strategies for protecting raptor populations and habitat from threats including development and climate change

Implications of cutthroat trout declines for breeding ospreys and bald eagles at Yellowstone Lake

In Yellowstone National Park (YNP), Ospreys (Pandion haliaetus) feed primarily on cutthroat trout (Oncorhynchus clarki bouvieri) and cutthroat trout represent approximately 23% of prey consumed by Bald Eagles (Haliaeetus leucocephalus) during the breeding season (Swenson 1978, Journal of Wildlife Management 42:87-90; Swenson et al. 1986, Wildlife Monographs 95:3-46). The introduction of exotic lake trout (Salvelinus namaycush) to Yellowstone Lake during the late 1980s caused substantial declines in populations of cutthroat trout. Historically, more than half of all breeding pairs of Ospreys and Bald Eagles in YNP have nested near and foraged at Yellowstone Lake and the decline in cutthroat trout numbers may affect rates of reproduction for these two species. We studied the relationship between an index of cutthroat trout abundance and spring weather on Osprey (1987-2009) and Bald Eagle (1987-2007) reproduction. We documented steep declines in an index of cutthroat trout abundance, Osprey productivity and nesting success, and a dramatic decline in the number of Osprey breeding pairs. Bald Eagle productivity and nesting success also declined, but at a slightly slower rate than that of Ospreys, and the number of breeding pairs of Bald Eagles increased over the study period. Osprey reproduction was positively correlated with an index of cutthroat trout abundance and spring temperatures. However, the relationship between Bald Eagle reproduction and the index of cutthroat trout abundance was unclear. Our study suggested that the recovery of cutthroat trout is important to maintaining a breeding population of Ospreys at Yellowstone Lake, but may be less important for the Yellowstone Lake Bald Eagle population. © 2013 The Raptor Research Foundation, Inc

Songbird response to increased willow (Salix spp.) growth in Yellowstone's northern range

Abstract. After nearly a century of height suppression, willows (Salix spp.) in the northern range of Yellowstone National Park, USA, are increasing in height growth as a possible consequence of wolf (Canis lupus) restoration, climate change, or other factors. Regardless of the drivers, the recent release of this rare but important habitat type could have significant implications for associated songbirds that are exhibiting declines in the region. Our objective was to evaluate bird response to releasing willows by comparing willow structure and bird community composition across three willow growth conditions: height suppressed, recently released, and previously tall (i.e., tall prior to the height increase of released willows). Released and previously tall willows exhibited high and similar vertical structure, but released willows were significantly lower in horizontal structure. Suppressed willows were significantly shorter and lower in horizontal cover than released or previously tall willows. Bird richness increased along a gradient from lowest in suppressed to highest in previously tall willows, but abundance and diversity were similar between released and previously tall willows, despite lower horizontal cover in the released condition. Common Yellowthroat (Geothlypis trichas) and Lincoln's Sparrow (Melospiza lincolnii ) were found in all three growth conditions; however, Yellow Warbler (Dendroica petechia), Warbling Vireo (Vireo gilvus), Willow Flycatcher (Empidonax traillii ), and Song Sparrow (Melospiza melodii ) were present in released and previously tall willows only. Wilson's Warbler (Wilsonia pusilla) was found in previously tall willows only, appearing to specialize on tall, dense willows. The results of our a priori habitat models indicated that foliage height diversity was the primary driver of bird richness, abundance, and diversity. These results indicate that vertical structure was a more important driver of bird community variables than horizontal structure and that riparian and willowdependent bird species have responded positively to increased willow growth in the region

Appendix A. Bird species observed in suppressed, released, and previously tall growth conditions in and around Yellowstone National Park's northern range.

Bird species observed in suppressed, released, and previously tall growth conditions in and around Yellowstone National Park's northern range

Managing central venous access during a health care crisis

10.1016/j.jvs.2020.06.112JOURNAL OF VASCULAR SURGERY7241184-