MicroRNAs influence hematopoietic differentiation, but little is known about their effects on the stem cell state. Here, we report that the microRNA processing enzyme Dicer is essential for stem cell ...persistence in vivo and a specific microRNA, miR-125a, controls the size of the stem cell population by regulating hematopoietic stem/progenitor cell (HSPC) apoptosis. Conditional deletion of Dicer revealed an absolute dependence for the multipotent HSPC population in a cell-autonomous manner, with increased HSPC apoptosis in mutant animals. An evolutionarily conserved microRNA cluster containing miR-99b, let-7e, and miR-125a was preferentially expressed in long-term hematopoietic stem cells. MicroRNA miR-125a alone was capable of increasing the number of hematopoietic stem cells in vivo by more than 8-fold. This result was accomplished through a differentiation stage-specific reduction of apoptosis in immature hematopoietic progenitors, possibly through targeting multiple proapoptotic genes. Bak1 was directly down-regulated by miR-125a and expression of a 3'UTR-less Bak1 blocked miR-125a-induced hematopoietic expansion in vivo. These data demonstrate cell-state-specific regulation by microRNA and identify a unique microRNA functioning to regulate the stem cell pool size.
Achieving state wildlife agency goals for white-tailed deer (Odocoileus virginianus) management may conflict with hunter traditions and desires. Optimizing deer herd management given conflicting ...biological and social goals means that agencies will need to better understand what trade-offs can be made. In North Carolina, USA, the harvest of deer by hunters is skewed towards males <2.5 years old and all firearm hunting seasons begin prior to the rut. Both trends can have undesirable consequences for deer populations, hunters, and deer managers. To provide better information to mitigate the potential for undesirable consequences, we modeled deer hunter choice behavior using a discrete choice experiment to identify their preferences for regulatory components and policy alternatives. Discrete choice experiments explain the choice behavior of humans via preference elicitation. We obtained the data used in our analysis after contacting 171,880 resident deer hunters by email and postcard to encourage their participation in a web-based survey. We received valid responses from 25,508 resident deer hunters. Respondents identified gun season length as the most important regulatory attribute influencing their decisions about policy, followed by bag limits. Results also suggest that North Carolina’s hunters may be more willing to make trade-offs when attributes least affecting their decision making, such as season opening date and blackpowder season length, are altered by decision makers to benefit the deer herd. By employing wildlife valuation methods, such as discrete choice experiments, agencies can gain deep insights into viable trade-offs between different attributes that underpin multidimensional policies, such as deer seasons, not achieved through attitudinal measures alone.
Crohn's disease is a relapsing and remitting inflammatory disorder with a variable clinical course. Although most patients present with an inflammatory phenotype (B1), approximately 20% of patients ...rapidly progress to complicated disease, which includes stricturing (B2), within 5 years. We analyzed DNA methylation patterns in blood samples of pediatric patients with Crohn's disease at diagnosis and later time points to identify changes that associate with and might contribute to disease development and progression.
We obtained blood samples from 164 pediatric patients (1–17 years old) with Crohn's disease (B1 or B2) who participated in a North American study and were followed for 5 years. Participants without intestinal inflammation or symptoms served as controls (n = 74). DNA methylation patterns were analyzed in samples collected at time of diagnosis and 1–3 years later at approximately 850,000 sites. We used genetic association and the concept of Mendelian randomization to identify changes in DNA methylation patterns that might contribute to the development of or result from Crohn's disease.
We identified 1189 5′-cytosine–phosphate–guanosine-3′ (CpG) sites that were differentially methylated between patients with Crohn's disease (at diagnosis) and controls. Methylation changes at these sites correlated with plasma levels of C-reactive protein. A comparison of methylation profiles of DNA collected at diagnosis of Crohn's disease vs during the follow-up period showed that, during treatment, alterations identified in methylation profiles at the time of diagnosis of Crohn's disease more closely resembled patterns observed in controls, irrespective of disease progression to B2. We identified methylation changes at 3 CpG sites that might contribute to the development of Crohn's disease. Most CpG methylation changes associated with Crohn's disease disappeared with treatment of inflammation and might be a result of Crohn's disease.
Methylation patterns observed in blood samples from patients with Crohn's disease accompany acute inflammation; with treatment, these change to resemble methylation patterns observed in patients without intestinal inflammation. These findings indicate that Crohn's disease–associated patterns of DNA methylation observed in blood samples are a result of the inflammatory features of the disease and are less likely to contribute to disease development or progression.
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Despite being politicized in its early stages, the Red Wolf (Canis rufus) Recovery Program (RWRP) existed for 30 years in eastern North Carolina with little attention paid to finding common ground ...between policy contestants. We situated our data from 62 key informant interviews within Stone's (2002) policy goals framework to evaluate red wolf recovery in eastern North Carolina, United States. Four goals underpin U.S. political culture and offer common ground with which to begin negotiation among policy contestants. Our results highlight challenges to achieving one definition prescribing how to treat each policy goal. The future of recovery within the red wolf's historic range could hinge on decision-makers' willingness to prioritize policy design over policy tool evaluation, developing a process by which to achieve an agreed-upon set of values underscoring red wolf recovery. This process must reconcile disagreements about what is fair or equitable treatment of landowners and include local-level experiences.
The recent co-occurrence of red wolves (Canis rufus) and coyotes (Canis latrans) in eastern North Carolina provides a unique opportunity to study prey partitioning by sympatric canids. We collected ...scats from this region and examined them for prey contents. We used fecal DNA analysis to identify which taxa deposited each scat and multinomial modeling designed for mark–recapture data to investigate diets of sympatric red wolves and coyotes. Diets of red wolves and coyotes did not differ, but the proportion of small rodents in the composite scats of both canids was greater in the spring than in the summer. White-tailed deer (Odocoileus virginianus), rabbits (Sylvilagus spp.), and small rodents were the most common diet items in canid scats. The similarity of diet between red wolves and coyotes suggests that these 2 species may be affecting prey populations similarly.
Populations of American Alligators (Alligator mississippiensis) generally are considered more abundant at present than historically; however, little information exists to assess the population of ...alligators in North Carolina at the northern extent of the species' range. Investigation of the factors influencing the distribution and abundance of alligators in North Carolina could shed light on the species' response to rapid environmental change in the region. We conducted a two-phase study: 1) to assess the distribution of alligators in North Carolina using a site-occupancy design; and 2) to assess the patterns in abundance using a repeated sampling design for population estimation. Results showed that both occupancy and abundance decreased in more northern sites, in sites with higher salinity, and in sites that were generally more westward. Sites sampled later in June were more likely to be occupied than those sampled earlier in the month. Abundance also increased with greater shoreline vegetation complexity and varied between lakes, rivers, and estuaries. Compared with studies from 30 years prior, the population seems fairly stable in terms of abundance and distribution. Given the northern limits of the species and the negative association with salinity, continued monitoring is warranted to understand changes in distribution and abundance with respect to predicted rates of sea-level rise, salinization, and urbanization locally around coastal cities like Wilmington.
When hybridizing species come into contact, understanding the processes that regulate their interactions can help predict the future outcome of the system. This is especially relevant in conservation ...situations where human activities can influence hybridization dynamics. We investigated a developing hybrid zone between red wolves and coyotes in North Carolina, USA to elucidate patterns of hybridization in a system heavily managed for preservation of the red wolf genome. Using noninvasive genetic sampling of scat, we surveyed a 2880 km2 region adjacent to the Red Wolf Experimental Population Area (RWEPA). We combined microsatellite genotypes collected from this survey with those from companion studies conducted both within and outside the RWEPA to describe the gradient of red wolf ancestry. A total of 311 individuals were genotyped at 17 loci and red wolf ancestry decreased along an east–west gradient across the RWEPA. No red wolves were found outside the RWEPA, yet half of individuals found within this area were coyotes. Hybrids composed only 4% of individuals within this landscape despite co‐occurrence of the two species throughout the RWEPA. The low proportion of hybrids suggests that a combination of active management and natural isolating mechanisms may be limiting intermixing within this hybrid system.
Painted Buntings (Passerina ciris) have been declining in the southeastern United States since the 1970s. A recent demographic assessment highlighted the importance of estimating demographic ...parameters, which have received little attention to date. The dearth of information is troublesome because attempts to reverse declining trends require a better understanding of the relationship between habitat quality and age- and sex-specific survival and recruitment rates. We used capture–mark–recapture data collected from 2007 to 2015 on Bald Head Island (BHI) and at Hammocks Beach State Park (HBSP) in North Carolina, USA, to estimate local age- and sex-specific annual survival rates and local population size and recruitment rates using programs MARK and LOLASURVIV. Juveniles had lower local survival rates than adults (HBSP: 0.28 ± 0.14 vs. 0.67 ± 0.06; BHI: 0.28 ± 0.04 vs. 0.57 ± 0.02). Local annual survival rates for males on BHI (0.50 ± 0.03) were lower than those for females (0.57 ± 0.02). Age-specific differences were consistent with known differential age-dependent survival skills, and sex-specific differences were consistent with the potential influence of sexual dichromism. Conservative estimates of population size on BHI averaged 101 juveniles and 263 adults annually. Annual in situ reproductive recruitment averaged 28 individuals plus an additional 120 new immigrants, indicating successful reproduction and connectivity with neighboring coastal populations. Local adult survival estimates from our 2 North Carolinian study populations were similar to high-end estimates from across the eastern and western range of the species (∼0.60). Finite observed population growth rate estimates between the BHI population (λ = 1.10) and a South Carolinian population (λ = 0.87) underscore the potential role of differential habitat quality and the importance of information from multiple sites, including nonbreeding grounds, for proper inferences about the status of the species. Reported vital rates provide a stronger foundation on which to base habitat quality as assessed with demographic parameters and to guide Painted Bunting conservation regionally.
Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications ...for future biosphere-atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analysed across species and biomes using a standardized physiological framework. Here, we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.
Spring wild turkey (Meleagris gallopavo) hunting is a foundational activity for many hunters across North America. Managing turkey hunters and turkey hunting is, therefore, a priority for state and ...provincial fish and wildlife management agencies. Early stages of the current SARS‐CoV‐2 (COVID‐19) pandemic in the United States coincided with 2020 spring turkey hunting seasons across the U.S. Potential effects of increases in peoples' time available for hunting on effort and turkey populations could have been substantial. We surveyed the primary wildlife biologist tasked with wild turkey management for each state and provincial jurisdiction with a huntable wild turkey population to determine turkey hunter and hunting dynamics before and during the spring 2020 turkey season. Biologists in 47 states responded to the survey. Results varied among states but hunting license sales, the number of hunters afield, harvest, total hunter‐days afield, and the number of days individual hunters were afield were greater in 2020 than the mean from the previous 3 years (2017–2019) in many states. Although hunting effort and total reported harvest increased in most states in 2020 from the previous 3‐year average, take‐per‐unit‐effort (i.e., harvest per hunter day) decreased in 93% of jurisdictions from which data were available, supporting the finding that increases in turkey harvest in spring 2020 were a result of a COVID‐related increase in participation and effort and not increases in turkey abundance. We recommend using these reference data for turkey population and turkey hunter monitoring pre‐ and post‐pandemic. Monitoring efforts should include wildlife population and habitat evaluations and study of hunter dynamics in a social science framework.
We evaluated turkey hunter and hunting dynamics before and during the spring 2020 turkey season corresponding with the outbreak of the 2020 COVID‐19 pandemic. Hunting license sales, the number of hunters afield, harvest, total hunter‐days afield, and the number of days individual hunters were afield increased in 2020. Although hunting effort and total reported harvest increased in most states, take‐per‐unit‐effort decreased in 93% of jurisdictions, supporting the finding that increases in turkey harvest in spring 2020 were a result of a COVID‐related increase in participation and effort and not increases in turkey abundance.
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