Modeling Sustainability of Arctic Communities: An Interdisciplinary Collaboration of Researchers and Local Knowledge Holders

How will climate change affect the sustainability of Arctic villages over the next 40 years? This question motivated a collaboration of 23 researchers and four Arctic communities (Old Crow, Yukon Territory, Canada; Aklavik, Northwest Territories, Canada; Fort McPherson, Northwest Territories, Canada; and Arctic Village, Alaska, USA) in or near the range of the Porcupine Caribou Herd. We drew on existing research and local knowledge to examine potential effects of climate change, petroleum development, tourism, and government spending cutbacks on the sustainability of four Arctic villages. We used data across eight disciplines to develop an Arctic Community Synthesis Model and a Web-based, interactive Possible Futures Model. Results suggested that climate warming will increase vegetation biomass within the herd’s summer range. However, despite forage increasing, the herd was projected as likely to decline with a warming climate because of increased insect harassment in the summer and potentially greater winter snow depths. There was a strong negative correlation between hypothetical, development-induced displacement of cows and calves from utilized calving grounds and calf survival during June. The results suggested that climate warming coupled with petroleum development would cause a decline in caribou harvest by local communities. Because the Synthesis Model inherits uncertainties associated with each component model, sensitivity analysis is required. Scientists and stakeholders agreed that (1) although simulation models are incomplete abstractions of the real world, they helped bring scientific and community knowledge together, and (2) relationships established across disciplines and between scientists and communities were a valuable outcome of the study. Additional project materials, including the Web-based Possible Futures Model, are available at http://www.taiga.net/sustain.     

The Kaposi's sarcoma-associated herpesvirus complement control protein mimics human molecular mechanisms for inhibition of the complement system

Kaposi's sarcoma-associated human herpesvirus (KSHV) is thought to cause Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Previously, we reported that the KSHV complement control protein (KCP) encoded within the viral genome is a potent regulator of the complement system; it acts both as a cofactor for factor I and accelerates decay of the C3 convertases (Spiller, O. B., Blackbourn, D. J., Mark, L., Proctor, D. G., and Blom, A. M. (2003) J. Biol. Chem. 278, 9283-9289). KCP is a homologue to human complement regulators, being comprised of four complement control protein (CCP) domains. In this, the first study to identify the functional sites of a viral homologue at the amino acid level, we created a three-dimensional homology-based model followed by site-directed mutagenesis to locate complement regulatory sites. Classical pathway regulation, both through decay acceleration and factor I cleavage of C4b, required a cluster of positively charged amino acids in CCP1 stretching into CCP2 (Arg-20, Arg-33, Arg-35, Lys-64, Lys-65, and Lys-88) as well as positively (Lys-131, Lys-133, and His-135) and negatively (Glu-99, Glu-152, and Asp-155) charged areas at opposing faces of the border region between CCPs 2 and 3. The regulation of the alternative pathway (via factor I-mediated C3b cleavage) was found to both overlap with classical pathway regulatory sites (Lys-64, Lys-65, Lys-88 and Lys-131, Lys-133, His-135) as well as require unique, more C-terminal residues in CCPs 3 and 4 (His-158, His-171, and His-213) and CCP 4 (Phe-195, Phe-207, and Leu-209). We show here that KCP has evolved to maintain the spatial structure of its functional sites, especially the positively charged patches, compared with host complement regulators.     

Hydrologic and behavioral constraints on oviposition of stream insects: implications for adult dispersal

The supply of recruits plays an important role in plant and animal population dynamics, and may be governed by environmental and behavioral constraints on animals. Mated females of the mayfly genus Baetis alight on rocks protruding from streams, crawl under water and deposit a single egg mass under a rock. We surveyed oviposition and emergence of a bivoltine population of B. bicaudatus in multiple stream reaches in one high-altitude watershed in western Colorado over 3 years to establish qualitative patterns at a regional scale (entire watershed), and quantitative patterns over six generations at a local scale (one stream reach). We also measured characteristics of preferred oviposition substrates, performed experiments to test hypotheses about cues used by females to select oviposition sites, and measured mortality of egg masses in the field. Our goals were to determine whether: (1) hydrologic variation necessitated dispersal of females to find suitable oviposition sites; (2) the local supply of females could provide the supply of local recruits; and (3) local recruitment determined the local production of adults. The onset of oviposition corresponded with the decline of spring run-off, which differed dramatically among years and among sites within years. However, eggs appeared before any adults had emerged in 8 of 22 site-years, and adults emerged 2-3 weeks before any eggs were oviposited in 3 site-years. Furthermore, the size distribution of egg masses differed from that predicted by the size distribution of females that emerged from seven of nine stream reaches. Protruding rocks and eggs appeared earlier each summer in smaller tributaries than in larger mainstream reaches, suggesting that hydrologic and behavioral constraints on oviposition may force females to disperse away from their natal reach to oviposit, and possibly explain the predominantly upstream flight of Baetis females reported in other studies. Local oviposition rates in one third-order stream-reach increased rapidly as soon as substrates protruded from the water surface, and females preferred large rocks that became available early in the flight season. However, females oviposited on <10% of all available rocks, and <65% of preferred rocks as determined by an empirical model. These data indicated that the timing of appearance of suitable oviposition sites determined the phenology of local recruitment, but that preferred oviposition sites were not saturated. Thus, the magnitude of local recruitment was not limited by the absolute abundance of preferred oviposition sites. Only 22% of egg masses observed in the field suffered mortality during their embryonic development, and per capita Baetis egg mass mortality was significantly lower on rocks with higher densities of egg masses. Thus, we suspect that specialized oviposition behavior may reduce the probability of egg mortality, potentially compensating for the costs of dispersal necessary to locate suitable oviposition sites. Finally, the number of adults that emerged at one stream reach was independent of the number of egg masses oviposited over six generations of Baetis; and local recruitment was not a function of the number of adults of the previous generation that emerged locally. The patterns of oviposition and emergence of Baetis found in this study are consistent with the following hypotheses. Recruitment of eggs in a stream reach is not limited by the local supply of adults, but is a function of the regional supply of dispersing adults, which are constrained by the spatial and temporal distribution of preferred oviposition habitat. Furthermore, subsequent local production of adults is not a function of the supply of recruits, arguing for post-recruitment control of local populations by processes operating in the larval stage (e.g., predation, competition, dispersal, disturbance). Processes affecting larval and adult stages of Baetis act independently and at different scales, thereby decoupling local population dynamics of successive generations.     

Physician Survey to Determine How Dengue Is Diagnosed,Treated and Reported in Puerto Rico

Dengue is a major cause of morbidity in Puerto Rico and is well-known to its physicians. Early case identification and timely initiation of treatment for patients with severe dengue can reduce medical complications and mortality. To determine clinical management and reporting practices, and assess knowledge of dengue and its management, a survey was sent to 2,512 physicians with a medical license in Puerto Rico. Of the 2,313 physicians who received the survey, 817 (35%) completed the questionnaire. Of the respondents, 708 were currently practicing medicine; 138 were board certified (Group 1), 282 were board eligible (Group 2), and 288 had not finished residency (Group 3). Although respondents clinically diagnosed, on average, 12 cases of dengue in the preceding three months, 31% did not report any suspected cases to public health officials while about half (56%) reported all cases. Overall, 29% of respondents correctly identified early signs of shock and 48% identified severe abdominal pain and persistent vomiting as warning signs for severe dengue with the proportion of correct respondents highest in Group 1. Reportedly about sixty percent (57%) appropriately never give corticosteroids or prophylactic platelet transfusions to dengue patients. One third (30%) of respondents correctly identified administration of intravenous colloid solution as the best treatment option for dengue patients with refractory shock and elevated hematocrit after an initial trial of intravenous crystalloids, and nearly one half (46%) correctly identified administration of a blood transfusion as the best option for dengue patients with refractory shock and decreased hematocrit after a trial of intravenous crystalloids. Even though dengue has been endemic in Puerto Rico for nearly 4 decades, knowledge of dengue management is still limited, compliance with WHO treatment guidelines is suboptimal, and underreporting is significant. These findings were used to design a post graduate training course to improve the clinical management of dengue.     

Considerations for operational space definition and optimization of a no-salt flowthrough hydrophobic interaction chromatography purification step

No-salt flowthrough hydrophobic interaction chromatography (HIC) has been shown to effectively remove process and product-related impurities from bioprocess streams. In this publication, a panel of six antibodies has been used to demonstrate operating principles for the application of no-salt flowthrough HIC in antibody purification processes. The results indicate that no-salt flowthrough HIC provides robust aggregate clearance across operating conditions including flow rate, and variations in resin ligand density. Additionally, HMW reduction has an optimal pH range relative to the isoelectric point of each molecule and high molecular weight (HMW) reduction can be improved by altering the total protein load and/or HMW concentration to drive binding of high molecular weight species to the resin.     

Frequency of hybridization between Ostrinia nubilalis E‐and Z‐pheromone races in regions of sympatry within the United States

Female European corn borer, Ostrinia nubilalis, produce and males respond to sex pheromone blends with either E‐ or Z‐Δ11‐tetradecenyl acetate as the major component. E‐ and Z‐race populations are sympatric in the Eastern United States, Southeastern Canada, and the Mediterranean region of Europe. The E‐ and Z‐pheromone races of O. nubilalis are models for incipient species formation, but hybridization frequencies within natural populations remain obscure due to lack of a high‐throughput phenotyping method. Lassance et al. previously identified a pheromone gland‐expressed fatty‐acyl reductase gene (pgfar) that controls the ratio of Δ11‐tetradecenyl acetate stereoisomers. We identified three single nucleotide polymorphism (SNP) markers within pgfar that are differentially fixed between E‐ and Z‐race females, and that are ≥98.2% correlated with female pheromone ratios measured by gas chromatography. Genotypic data from locations in the United States demonstrated that pgfar‐z alleles were fixed within historically allopatric Z‐pheromone race populations in the Midwest, and that hybrid frequency ranged from 0.00 to 0.42 within 11 sympatric sites where the two races co‐occur in the Eastern United States (mean hybridization frequency or heterozygosity (H_O) = 0.226 ± 0.279). Estimates of hybridization between the E‐ and Z‐races are important for understanding the dynamics involved in maintaining race integrity, and are consistent with previous estimates of low levels of genetic divergence between E‐ and Z‐races and the presence of weak prezygotic mating barriers.     

Genetic rescue in a plant polyploid complex: Case study on the importance of genetic and trait data for conservation management

Knowledge of the biology of rare plant species is indispensable to aid their survival and to inform efficient conservation actions, but in many cases relevant data are lacking. In addition, while studies of conservation genetics have provided a wealth of information on the considerations arising from inbreeding, mate limitation, or local adaptation, the impact of intraspecific polyploidy remains understudied. In this study, we examined the breeding system of the rare Australian daisy Rutidosis lanata (Asteraceae) and screened ten of its populations for their ploidy level to develop recommendations for management actions, in particular, with regard to seed sourcing and genetic rescue. We found R. lanata to represent a polyploid complex, with tetraploid, pentaploid and hexaploid individuals coexisting in the same species. Crossing experiments confirmed R. lanata to be self‐incompatible. Mate availability varied from c. 49% to c. 76% across populations. Most populations showed mate availability of c. 50%–70%, suggesting that mate limitation resulting from a lack of local genetic diversity may cause or at least contribute to reduced seed set. Crossing between populations resulted in significantly higher reproductive success for all populations except one, suggesting the possibility of genetic rescue through population mixing. However, the crossing experiments also showed that pentaploids suffer from a severely reduced paternal reproductive fitness. Any additional hybrids between tetraploids and pentaploids, as would be created by mixing populations with different genome copy numbers during conservation work, would consequently exacerbate mate limitation and thus reduce population viability. We conclude that seed set and thus population viability can be maximized by mixing populations with the same number of genome copies, but that populations with different numbers should be kept spatially separated. The case of Rutidosis lanata provides an example and a potential template for examining the conservation genetics of other species that may constitute polyploid complexes.     

Neuraminidase-Inhibiting Antibody Is a Correlate of Cross-Protection against Lethal H5N1 Influenza Virus in Ferrets Immunized with Seasonal Influenza Vaccine

In preparing for the threat of a pandemic of avian H5N1 influenza virus, we need to consider the significant delay (4 to 6 months) necessary to produce a strain-matched vaccine. As some degree of cross-reactivity between seasonal influenza vaccines and H5N1 virus has been reported, this was further explored in the ferret model to determine the targets of protective immunity. Ferrets were vaccinated with two intramuscular inoculations of trivalent inactivated split influenza vaccine or subcomponent vaccines, with and without adjuvant, and later challenged with a lethal dose of A/Vietnam/1203/2004 (H5N1) influenza virus. We confirmed that vaccination with seasonal influenza vaccine afforded partial protection against lethal H5N1 challenge and showed that use of either AlPO₄ or Iscomatrix adjuvant with the vaccine resulted in complete protection against disease and death. The protection was due exclusively to the H1N1 vaccine component, and although the hemagglutinin contributed to protection, the dominant protective response was targeted toward the neuraminidase (NA) and correlated with sialic acid cleavage-inhibiting antibody titers. Purified heterologous NA formulated with Iscomatrix adjuvant was also protective. These results suggest that adjuvanted seasonal trivalent vaccine could be used as an interim measure to decrease morbidity and mortality from H5N1 prior to the availability of a specific vaccine. The data also highlight that an inducer of cross-protective immunity is the NA, a protein whose levels are not normally monitored in vaccines and whose capacity to induce immunity in recipients is not normally assessed.