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2020. The lead (Pb) lining of agriculture-related subsidies:enhanced Golden Eagle growth rates tempered by Pb exposure. Ecosphere 11(1):Abstract. Supplementary food resources (e.g., subsidies) associated with agriculture can benefit wildlife species, increasing predictability and availability of food. Avian scavengers including raptors often utilize subsidies associated with both recreational hunting and pest shooting on agricultural lands. However, these subsidies can contain lead (Pb) fragments if they are culled with Pb-based ammunition, potentially leading to Pb poisoning and physiological impairment in wildlife. Nesting Golden Eagles (Aquila chrysaetos) commonly forage in agricultural lands during the breeding season, and therefore, both adults and their nestlings are susceptible to Pb exposure from scavenging shot wildlife. We assessed drivers of Pb exposure in 258 nestling Golden Eagles (401 total blood samples), along with physiological and growth responses, in agricultural lands across four western states in the United States. We also evaluated the birds' Pb stable isotope signatures to inform exposure sources. Twenty-six percent of Golden Eagle nestlings contained Pb concentrations associated with subclinical poisoning for sensitive species (0.03-0.2 lg/g ww), 4% had Pb concentrations that exceeded subclinical poisoning benchmarks (0.2-0.5 lg/g ww), and <1% exceeded either concentrations associated with clinical poisoning (0.5-1.0 lg/g ww) and or those deemed to cause severe clinical poisoning (>1.0 lg/g ww). Lead concentrations were highest in nestlings with close proximity to fields that potentially provided subsidies and declined exponentially as distance to subsidies increased. However, close proximity to agriculture, and presumably subsidies, positively influenced nestling growth rates. Across the range of Pb exposure, nestlings experienced a 67% reduction in delta-aminolevulinic acid dehydratase (d-ALAD) activity, suggesting nestlings may have been anemic or experiencing cellular damage. Isotopic ratios of 206 Pb/ 207 Pb increased non-linearly with increasing blood Pb in Golden Eagle nestlings, and 45% of the birds were consistent with those of ammunition. However, above 0.10 lg/g ww, the proportion associated with ammunition increased to 89% of the nestlings. An improved understanding of how these positive (growth) and negative (physiology) effects associated with proximity to subsidies interact would be beneficial to managers when considering management scenarios and potentially evaluating any measures taken to reduce Pb exposure across the landscape.

Previous studies documented poor productivity of bald eagles (Haliaeetus leucocephalus) in the lower Columbia River (LCR), USA, and elevated p,p'-dichlorodiphenyldichloroethylene (DDE), polychlorinated biphenyls (PCBs), dioxins, and furans in eagle eggs. From 1994 to 1995, we collected partially incubated eggs at 19 of 43 occupied territories along the LCR and compared productivity and egg contaminants to values obtained in the mid-1980s. We found higher productivity at new nesting sites along the river, yet productivity at 23 older breeding territories remained low and was not different (p = 0.713) between studies. Eggshell thickness at older territories had not improved (p = 0.404), and eggshells averaged 11% thinner than shells measured before dichlorodiphenyltrichloroethane use. Decreases in DDE (p = 0.022) and total PCBs (p = 0.0004) in eggs from older breeding areas occurred between study periods. Productivity was not correlated to contaminants, but DDE, PCBs, and dioxin-like chemicals exceeded estimated no-effect values. Some dioxin-like contaminants in eggs were correlated to nest location, with highest concentrations occurring toward the river's mouth where productivity was lowest. Although total productivity increased due to the success of new nesting pairs in the region, egg contaminants remain high enough to impair reproduction at older territories and, over time, may alter productivity of new pairs nesting near the river's mouth.

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An individual's investment in constitutive immune defenses depends on both intrinsic and extrinsic factors. We examined how Leucocytozoon parasite presence, body condition (scaled mass), heterophil-to-lymphocyte (H:L) ratio, sex, and age affected immune defenses in golden eagle (Aquila chrysaetos) nestlings from three regions: California, Oregon, and Idaho. We quantified hemolytic-complement activity and bacterial killing ability, two measures of constitutive immunity. Body condition and age did not affect immune defenses. However, eagles with lower H:L ratios had lower complement activity, corroborating other findings that animals in better condition sometimes invest less in constitutive immunity. In addition, eagles with Leucocytozoon infections had higher concentrations of circulating complement proteins but not elevated opsonizing proteins for all microbes, and eagles from Oregon had significantly higher constitutive immunity than those from California or Idaho. We posit that Oregon eagles might have elevated immune defenses because they are exposed to more endoparasites than eagles from California or Idaho, and our results confirmed that the OR region has the highest rate of Leucocytozoon infections. Our study examined immune function in a free-living, long-lived raptor species, whereas most avian ecoimmunological research focuses on passerines. Thus, our research informs a broad perspective regarding the evolutionary and environmental pressures on immune function in birds.

De novo designed peptides that self-assemble into cross-β rich fibrillar biomaterials have been pursued as an innovative platform for the development of adjuvant- and inflammation-free vaccines. However, they share structural properties similar to amyloid species implicated in neurodegenerative diseases, which has been a long-standing concern for their translation. Here, we comprehensively characterize the amyloidogenic character of the amphipathic self-assembling cross-β peptide KFE8, compared to pathological amyloid-like proteins α-synuclein (α-syn) and TDP-43. Further, we developed plasmid-based DNA vaccines with the KFE8 backbone serving as a fibrillizing scaffold for delivery of a GFP model antigen. We find that expression of tandem repeats of KFE8 is non-toxic and can be efficiently cleared by autophagy. We also demonstrate that synthetic KFE8 nanofibers do not cross-seed amyloid formation of α-syn in mammalian cells compared to α-syn preformed fibrils. In mice, vaccination with plasmids encoding the KFE32-GFP fusion protein elicited robust immune responses, inducing production of significantly higher levels of anti-GFP antibodies compared to soluble GFP or α-syn tagged GFP. Antigen-specific CD8+T cells were also detected in the spleens of vaccinated mice and cytokine profiles from antigen recall assays indicate a balanced Th1/Th2 response. These findings illustrate that cross-β-rich peptide nanofibers have distinct properties from those of pathological amyloidogenic proteins, and are an attractive platform for the development of DNA vaccines with self-adjuvanting properties and improved safety profiles.

Paperback, $18.00 USD. ''I've been using lead all my life,'' he continued, becoming more aggressive. He pulled a plastic bag from the inside of his jacket and held it at eye level. Three muzzleloader bullets hung heavy at the bottom. ''Are you going to tell me these fragmented on elk?'' Apparently, author Mike McTee likes a challenge, evidenced by his willingness to engage with the hunter quoted above in his book Wilted Wings, A Hunter's Fight for Eagles as well as his eagerness to address a seemingly simple yet complex environmental question: What happens when raptors and other scavengers eat the remains of animals shot with lead ammunition?McTee dives into the issue with clear devotion to, and experience with, the lead ammunition conundrum. The reader doesn't even get through the Prologue before being introduced to an eagle found in the wild unable to fly, the graphic symptoms it was experiencing, and the efforts the local rehabilitators undertook to keep the eagle alive. This is the first of many lead-poisoned eagles the author will encounter as he works his way through graduate school to the point of his employment as a wildlife researcher at a ranch in Montana. Along this journey, McTee details his own hunting experiences used to keep his freezer full of meat. . .until one elk hunt compels him to really question why he still has a lead bullet chambered in his rifle.Yet, I should emphasize that this is not just a story about hunting. This is a story about raptors and raptor biology, the science of lead poisoning, the dedication of rehabilitators and conservationists, political meddling, and human hubris.The blend of science and hunting stories along with the author's first-hand experience in the field gives the book a ''can't put it down'' quality. Chapter 6 (The Copper Option) is a good example of how the entire book flows-McTee artfully weaves the history of bullet manufacturers, misconceptions about non-lead bullets and performance, and issues surrounding lead in California Condors (Gymnogyps californianus) in between his own compelling hunting stories.These chapters convey, in a new and interesting way, the topic of ammunition-based lead poisoning that most readers of the Journal of Raptor Research have likely encountered before. . .maybe in a waterfowl class, in the

Lead (Pb) exposure is a widespread wildlife conservation threat. Although commonly associated with Pb-based ammunition from big-game hunting, small mammals (e.g., ground squirrels) shot for recreational or pest-management purposes represent a potentially important Pb vector in agricultural regions. We measured the responses of avian scavengers to pest-shooting events and examined their Pb exposure through consumption of shot mammals. There were 3.4-fold more avian scavengers at shooting fields relative to those at fields with no recent shooting, and avian scavengers spent 1.8-fold more time feeding after recent shooting events. We isotopically labeled shot ground squirrels in the field with an enriched 15N isotope tracer; 6% of avian scavengers sampled within a 39 km radius reflected this tracer in their blood. However, 33% of the avian scavengers within the average foraging dispersal distance of nests (0.6–3.7 km) were labeled, demonstrating the importance of these shooting fields as a source of food for birds nesting in close proximity. Additionally, Pb concentrations in 48% of avian scavengers exceeded subclinical poisoning benchmarks for sensitive species (0.03–0.20 μg/g w/w), and those birds exhibited reduced δ-aminolevulinic acid dehydratase activity, indicating a biochemical effect of Pb. The use of shooting to manage small mammal pests is a common practice globally. Efforts that can reduce the use of Pb-based ammunition may lessen the negative physiological effects of Pb exposure on avian scavengers.