A bending rigidity parameter for stress granule condensates.

Interfacial tension plays an important role in governing the dynamics of droplet coalescence and determining how condensates interact with and deform lipid membranes and biological filaments. We demonstrate that an interfacial tension-only model is inadequate for describing stress granules in live cells. Harnessing a high-throughput flicker spectroscopy pipeline to analyze the shape fluctuations of tens of thousands of stress granules, we find that the measured fluctuation spectra require an additional contribution, which we attribute to elastic bending deformation. We also show that stress granules have an irregular, nonspherical base shape. These results suggest that stress granules are viscoelastic droplets with a structured interface, rather than simple Newtonian liquids. Furthermore, we observe that the measured interfacial tensions and bending rigidities span a range of several orders of magnitude. Hence, different types of stress granules (and more generally, other biomolecular condensates) can only be differentiated via large-scale surveys.

MERISTEM-DEFECTIVE regulates the balance between stemness and differentiation in the root meristem through RNA splicing control.

Plants respond to environmental stresses through controlled stem cell maintenance and meristem activity. One level of gene regulation is RNA alternative splicing. However, the mechanistic link between stress, meristem function and RNA splicing is poorly understood. The MERISTEM-DEFECTIVE (MDF) Arabidopsis gene encodes an SR-related family protein, required for meristem function and leaf vascularization, and is the likely orthologue of the human SART1 and yeast Snu66 splicing factors. MDF is required for the correct splicing and expression of key transcripts associated with root meristem function. We identified RSZ33 and ACC1, both known to regulate cell patterning, as splicing targets required for MDF function in the meristem. MDF expression is modulated by osmotic and cold stress, associated with differential splicing and specific isoform accumulation and shuttling between nucleus and cytosol, and acts in part via a splicing target SR34. We propose a model in which MDF controls splicing in the root meristem to promote stemness and to repress stress response, cell differentiation and cell death pathways.

Genomic erosion in a demographically recovered bird species during conservation rescue.

The pink pigeon (Nesoenas mayeri) is an endemic species of Mauritius that has made a remarkable recovery after a severe population bottleneck in the 1970s to early 1990s. Prior to this bottleneck, an ex situ population was established from which captive-bred individuals were released into free-living subpopulations to increase population size and genetic variation. This conservation rescue led to rapid population recovery to 400-480 individuals, and the species was twice downlisted on the International Union for the Conservation of Nature (IUCN) Red List. We analyzed the impacts of the bottleneck and genetic rescue on neutral genetic variation during and after population recovery (1993-2008) with restriction site-associated sequencing, microsatellite analyses, and quantitative genetic analysis of studbook data of 1112 birds from zoos in Europe and the United States. We used computer simulations to study the predicted changes in genetic variation and population viability from the past into the future. Genetic variation declined rapidly, despite the population rebound, and the effective population size was approximately an order of magnitude smaller than census size. The species carried a high genetic load of circa 15 lethal equivalents for longevity. Our computer simulations predicted continued inbreeding will likely result in increased expression of deleterious mutations (i.e., a high realized load) and severe inbreeding depression. Without continued conservation actions, it is likely that the pink pigeon will go extinct in the wild within 100 years. Conservation rescue of the pink pigeon has been instrumental in the recovery of the free-living population. However, further genetic rescue with captive-bred birds from zoos is required to recover lost variation, reduce expression of harmful deleterious variation, and prevent extinction. The use of genomics and modeling data can inform IUCN assessments of the viability and extinction risk of species, and it helps in assessments of the conservation dependency of populations.

La paloma rosada (Nesoenas mayeri) es una especie endémica de Mauricio que se ha recuperado impresionantemente después de un grave cuello de botella poblacional a principios de la década de 1970 que duró hasta inicios de la década de 1990. Antes de este cuello de botella se había establecido una población ex situ de la cual se liberaban individuos reproducidos en cautiverio a las subpoblaciones en libertad para incrementar la variación genética y el tamaño poblacional. Este rescate de conservación derivó en una recuperación rápida de la población (400-480 individuos) y la especie cambió positivamente de categoría dos veces en la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza (UICN). Analizamos los impactos del cuello de botella y el rescate genético sobre la variación genética neutral durante y después de la recuperación poblacional (de 1993 a 2008) mediante secuenciación RAD, análisis de microsatélites y análisis genéticos cuantitativos de los datos del libro genealógico de 1112 aves ubicadas en zoológicos de Europa y los Estados Unidos. Usamos simulaciones por computadora para estudiar los cambios pronosticados en la variación genética y en la viabilidad poblacional del pasado hacia el futuro. La variación genética declinó rápidamente, a pesar de la recuperación poblacional, y el tamaño efectivo de la población fue aproximadamente un orden de magnitud más pequeño que el tamaño del censo. La especie contó con una carga genética elevada de casi 15 equivalentes letales para la longevidad. Nuestras simulaciones pronostican que la endogamia continua probablemente resultará en un incremento en la expresión de mutaciones deletéreas (es decir, una carga realizada elevada) y en una depresión endogámica severa. Sin acciones continuas para la conservación, es probable que la paloma rosada esté extinta en vida libre dentro de cien años. El rescate de conservación de la paloma rosada ha sido fundamental en la recuperación de la población silvestre; sin embargo, se requiere de un rescate genético adicional con las aves de reproducción en cautiverio de los zoológicos para recuperar la variación perdida, reducir la expresión de la variación deletérea dañina y prevenir la extinción. El uso de la genómica y los datos modelados puede orientar las valoraciones de la UICN sobre la viabilidad y el riesgo de extinción de las especies, además de que ayuda en la evaluación de la dependencia que tienen las poblaciones de la conservación.

Individual consistency in migration strategies of a tropical seabird, the Round Island petrel.

BACKGROUND: In migratory species, the extent of within- and between-individual variation in migratory strategies can influence potential rates and directions of responses to environmental changes. Quantifying this variation requires tracking of many individuals on repeated migratory journeys. At temperate and higher latitudes, low levels of within-individual variation in migratory behaviours are common and may reflect repeated use of predictable resources in these seasonally-structured environments. However, variation in migratory behaviours in the tropics, where seasonal predictability of food resources can be weaker, remains largely unknown. METHODS: Round Island petrels (Pterodroma sp.) are tropical, pelagic seabirds that breed all year round and perform long-distance migrations. Using multi-year geolocator tracking data from 62 individuals between 2009 and 2018, we quantify levels of within- and between-individual variation in non-breeding distributions and timings. RESULTS: We found striking levels of between-individual variation in at-sea movements and timings, with non-breeding migrations to different areas occurring across much of the Indian Ocean and throughout the whole year. Despite this, repeat-tracking of individual petrels revealed remarkably high levels of spatial and temporal consistency in within-individual migratory behaviour, particularly for petrels that departed at similar times in different years and for those departing in the austral summer. However, while the same areas were used by individuals in different years, they were not necessarily used at the same times during the non-breeding period. CONCLUSIONS: Even in tropical systems with huge ranges of migratory routes and timings, our results suggest benefits of consistency in individual migratory behaviours. Identifying the factors that drive and maintain between-individual variation in migratory behaviour, and the consequences for breeding success and survival, will be key to understanding the consequences of environmental change across migratory ranges.

Deep conservation of ribosome stall sites across RNA processing genes.

The rate of translation can vary depending on the mRNA template. During the elongation phase the ribosome can transiently pause or permanently stall. A pause can provide the nascent protein with the time to fold or be transported, while stalling can serve as quality control and trigger degradation of aberrant mRNA and peptide. Ribosome profiling has allowed for the genome-wide detection of such pauses and stalls, but due to library-specific biases, these predictions are often unreliable. Here, we take advantage of the deep conservation of protein synthesis machinery, hypothesizing that similar conservation could exist for functionally important locations of ribosome slowdown, here collectively called stall sites. We analyze multiple ribosome profiling datasets from phylogenetically diverse eukaryotes: yeast, fruit fly, zebrafish, mouse and human to identify conserved stall sites. We find thousands of stall sites across multiple species, with the enrichment of proline, glycine and negatively charged amino acids around conserved stalling. Many of the sites are found in RNA processing genes, suggesting that stalling might have a conserved role in RNA metabolism. In summary, our results provide a rich resource for the study of conserved stalling and indicate possible roles of stalling in gene regulation.

Larger polyethylene glenospheres in reverse shoulder arthroplasty: are they safe?

BACKGROUND: Reverse shoulder arthroplasty is gaining popularity owing to its proven longevity and good outcome scores. Scapular notching remains a concern. This study aimed to assess the safety of larger polyethylene glenospheres with increased eccentricity in comparison with the more conventional metal bearings. The secondary effects on scapular notching, clinical outcomes, range of movement, and complications were also analyzed. METHODS: We conducted a 10-year retrospective review of 145 SMR reverse shoulder arthroplasties (LimaCorporate, Udine, Italy) in 132 patients with radiographs at a minimum of 2 years postoperatively. The primary outcome measure was the survivorship of the larger polyethylene glenospheres. Secondary outcomes were the presence and size of notching, subjective satisfaction score, American Shoulder and Elbow Surgeons score, Oxford Shoulder Score, range of motion, and shoulder-related complications. RESULTS: No failures of the polyethylene glenospheres were noted in the 10-year period. At a minimum of 2 years' follow-up, notching was noted in 16 (25%) of the metal glenospheres vs. 9 (11.1%) of the polyethylene glenospheres (P = .028). The mean Oxford Shoulder Score was lower for the metal glenospheres (P = .005). Range of motion, complications, and overall satisfaction were similar in both groups. CONCLUSION: The inverted bearing configuration demonstrated no failures at a minimum of 2 years' follow-up. A larger study is required to determine whether the decreased incidence and size of early notching are related to the bearing size or material.

Unrestrained ESCRT-III drives micronuclear catastrophe and chromosome fragmentation.

The ESCRT-III membrane fission machinery maintains the integrity of the nuclear envelope. Although primary nuclei resealing takes minutes, micronuclear envelope ruptures seem to be irreversible. Instead, micronuclear ruptures result in catastrophic membrane collapse and are associated with chromosome fragmentation and chromothripsis, complex chromosome rearrangements thought to be a major driving force in cancer development. Here we use a combination of live microscopy and electron tomography, as well as computer simulations, to uncover the mechanism underlying micronuclear collapse. We show that, due to their small size, micronuclei inherently lack the capacity of primary nuclei to restrict the accumulation of CHMP7-LEMD2, a compartmentalization sensor that detects loss of nuclear integrity. This causes unrestrained ESCRT-III accumulation, which drives extensive membrane deformation, DNA damage and chromosome fragmentation. Thus, the nuclear-integrity surveillance machinery is a double-edged sword, as its sensitivity ensures rapid repair at primary nuclei while causing unrestrained activity at ruptured micronuclei, with catastrophic consequences for genome stability.

The movement ecology of the Mauritian flying fox (Pteropus niger): a long-term study using solar-powered GSM/GPS tags.

BACKGROUND: Flying foxes (Chiroptera: Pteropodidae) are large bats that often roost in the sun, hence solar-powered GPS/GSM devices can track their movements over extended periods. The endemic Mauritian flying fox (Pteropus niger) has recently been subjected to large-scale culling because of perceived damage to commercial fruit, and a consequent reduction in numbers of > 50% since 2015 resulted in its IUCN Red List Status being up-listed to Endangered. Determining its movements will be important for management and conservation, for understanding potential responses to environmental change, and for understanding population admixture. METHODS: Twelve bats were tagged with solar-powered GPS/GSM devices in 2014-2016. Tags remained active for up to almost a year (maximum 359 days: average 139 days (males) and 93 days (females)), providing some of the longest-term data on the movement ecology of bats yet obtained. Eight bats were probably hunted illegally, highlighting the scale of unauthorised persecution. RESULTS: Males travelled on average 9 km each night, females 6 km. The nightly distance covered by adults of both sexes was higher in winter than in summer, though the opposite pattern occurred for immature males. These differences are probably related to seasonal changes in fruit availability (adults) and to dispersal by immature males. The maximum distance covered during one night was > 92 km. Home ranges of males averaged 74,633 ha, females 31,072 ha. Core foraging areas averaged 2222 ha for males, 1364 ha for females. Fifty roosts were identified, mainly in forest fragments. As the bats disperse seeds of native plants that form forest canopies, conservation of the bats will potentially maintain and enhance native forest cover, in turn providing roosting sites for the bats. CONCLUSIONS: Solar-powered GSM tagging provides unprecedented potential for understanding the movement ecology of flying foxes. Mauritian flying foxes often move between the few remnant native forest fragments, which remain important for their conservation, and have potentially important roles in seed dispersal. Their nomadic movement fits with their panmictic genetic structure. Although their ability for long distance movements, sometimes over short timescales, permits rapid responses to local threats and environmental change, being restricted to Mauritius renders the bats extremely vulnerable to intense culling.

Hygiene and biosecurity protocols reduce infection prevalence but do not improve fledging success in an endangered parrot.

Emerging Infectious Diseases (EIDs) are recognised as global extinction drivers of threatened species. Unfortunately, biodiversity managers have few tested solutions to manage them when often the desperate need for solutions necessitates a response. Here we test in situ biosecurity protocols to assess the efficacy of managing Psittacine beak and feather disease (PBFD), one of the most common and emergent viral diseases in wild parrots (Psittaciformes) that is currently affecting numerous threatened species globally. In response to an outbreak of PBFD in Mauritius "echo" parakeets (Psittacula eques), managers implemented a set of biosecurity protocols to limit transmission and impact of Beak and feather disease virus (BFDV). Here we used a reciprocal design experiment on the wild population to test whether BFDV management reduced viral prevalence and viral load, and improved nestling body condition and fledge success. Whilst management reduced the probability of nestling infection by approximately 11% there was no observed impact on BFDV load and nestling body condition. In contrast to expectations there was lower fledge success in nests with added BFDV biosecurity (83% in untreated vs. 79% in treated nests). Our results clearly illustrate that management for wildlife conservation should be critically evaluated through targeted monitoring and experimental manipulation, and this evaluation should always focus on the fundamental objective of conservation.

An integrated transcriptional analysis of the developing human retina.

The scarcity of embryonic/foetal material as a resource for direct study means that there is still limited understanding of human retina development. Here, we present an integrated transcriptome analysis combined with immunohistochemistry in human eye and retinal samples from 4 to 19 post-conception weeks. This analysis reveals three developmental windows with specific gene expression patterns that informed the sequential emergence of retinal cell types and enabled identification of stage-specific cellular and biological processes, and transcriptional regulators. Each stage is characterised by a specific set of alternatively spliced transcripts that code for proteins involved in the formation of the photoreceptor connecting cilium, pre-mRNA splicing and epigenetic modifiers. Importantly, our data show that the transition from foetal to adult retina is characterised by a large increase in the percentage of mutually exclusive exons that code for proteins involved in photoreceptor maintenance. The circular RNA population is also defined and shown to increase during retinal development. Collectively, these data increase our understanding of human retinal development and the pre-mRNA splicing process, and help to identify new candidate disease genes.

The inter-teres approach to glenoid neck fractures: an alternative approach to glenoid fixation.

BACKGROUND: Scapula fractures are rare injuries that are generally treated nonoperatively. When surgery is performed, it is commonly undertaken through the posterior approach, which can be invasive and unforgiving on the soft tissues. We describe an alternative safe approach between teres major and minor that remains deep to a fascial sling formed by the combined infraspinatus and teres minor fasciae and deep to the primary nerve to teres minor, which is a terminal branch of the axillary nerve. METHODS: Between January 2008 and June 2014, there were 22 patients who underwent scapula fixation with this approach who were retrospectively identified and prospectively invited for clinical review by the American Shoulder and Elbow Surgeons (ASES) evaluation form and Constant score. Postoperative external rotation (ER) power in both abduction and adduction was also assessed. RESULTS: Five patients were lost to follow-up. All of the remaining patients were male with a mean age of 44.5 years (28-66 years). Mean follow-up time was 34.7 months (3-72 months). The mean ASES score for the 17 patients was 86.6 (41.6-100); the mean Constant score was 89.3 (22-100). The only significant factor affecting the ASES score was an ipsilateral neurologic upper limb injury. ER power was improved or equivalent to the contralateral side in 8 of the 10 patients assessed for ER; it was weaker in 2 patients, both of whom had surgical fixation of the vertebral border of the scapula. CONCLUSION: The inter-teres approach may be a safe alternative approach in glenoid fixation, although the loss of ER strength needs further evaluation.

Widespread gene flow between oceans in a pelagic seabird species complex.

Global-scale gene flow is an important concern in conservation biology as it has the potential to either increase or decrease genetic diversity in species and populations. Although many studies focus on the gene flow between different populations of a single species, the potential for gene flow and introgression between species is understudied, particularly in seabirds. The only well-studied example of a mixed-species, hybridizing population of petrels exists on Round Island, in the Indian Ocean. Previous research assumed that Round Island represents a point of secondary contact between Atlantic (Pterodroma arminjoniana) and Pacific species (Pterodroma neglecta and Pterodroma heraldica). This study uses microsatellite genotyping and tracking data to address the possibility of between-species hybridization occurring outside the Indian Ocean. Dispersal and gene flow spanning three oceans were demonstrated between the species in this complex. Analysis of migration rates estimated using bayesass revealed unidirectional movement of petrels from the Atlantic and Pacific into the Indian Ocean. Conversely, structure analysis revealed gene flow between species of the Atlantic and Pacific oceans, with potential three-way hybrids occurring outside the Indian Ocean. Additionally, geolocation tracking of Round Island petrels revealed two individuals travelling to the Atlantic and Pacific. These results suggest that interspecific hybrids in Pterodroma petrels are more common than was previously assumed. This study is the first of its kind to investigate gene flow between populations of closely related Procellariiform species on a global scale, demonstrating the need for consideration of widespread migration and hybridization in the conservation of threatened seabirds.

Contrasting effects of tropical cyclones on the annual survival of a pelagic seabird in the Indian Ocean.

Tropical cyclones are renowned for their destructive nature and are an important feature of marine and coastal tropical ecosystems. Over the last 40 years, their intensity, frequency and tracks have changed, partly in response to ocean warming, and future predictions indicate that these trends are likely to continue with potential consequences for human populations and coastal ecosystems. However, our understanding of how tropical cyclones currently affect marine biodiversity, and pelagic species in particular, is limited. For seabirds, the impacts of cyclones are known to be detrimental at breeding colonies, but impacts on the annual survival of pelagic adults and juveniles remain largely unexplored and no study has simultaneously explored the direct impacts of cyclones on different life-history stages across the annual life cycle. We used a 20-year data set on tropical cyclones in the Indian Ocean, tracking data from 122 Round Island petrels and long-term capture-mark-recapture data to explore the impacts of tropical cyclones on the survival of adult and juvenile (first year) petrels during both the breeding and migration periods. The tracking data showed that juvenile and adult Round Island petrels utilize the three cyclone regions of the Indian Ocean and were potentially exposed to cyclones for a substantial part of their annual cycle. However, only juvenile petrel survival was affected by cyclone activity; negatively by a strong cyclone in the vicinity of the breeding colony and positively by increasing cyclone activity in the Northern Indian Ocean where they spend the majority of their first year at sea. These contrasting effects raise the intriguing prospect that the projected changes in cyclones under current climate change scenarios may have positive as well as the more commonly perceived negative impacts on marine biodiversity.

The Dislocated Hip Hemiarthroplasty: Current Concepts of Etiological factors and Management.

BACKGROUND: Hip hemiarthroplasty (HA) following an intracapsular neck of femur fracture is an increasingly common procedure as a result of an ageing population. Patients are often frail and so morbidity and mortality figures are significant. As a result the National Institute for Health and Clinical Excellence (NICE) has formulated guidelines and a Best Practice Tariff (BPT) in an attempt to improve the care of such patients. Dislocation following HA is a potentially devastating complication with a reported incidence ranging from 1 to 15%. Multiple causative factors have been cited and studied in an effort to reduce the incidence of this complication which has a high rate of recurrence following the first episode and is associated with a high mortality rate and significant financial burden on the health economy. This paper reviews the available literature in an effort to identify the most pertinent factors affecting dislocation rates and thus reduce the incidence of this serious complication. METHODS: A comprehensive review of the literature was performed using the search engine PubMed with the keywords 'hip', 'hemiarthroplasty' and 'dislocation'. Two hundred and forty three articles were identified and assessed by the 3 authors independently. Data from fifty-two articles pertinent to the review on hemiarthroplasty dislocation epidemiology, risk factors and management were extracted in a standardised fashion. RESULTS: Following review of the papers multiple causative factors relating to HA dislocation were identified and grouped into 4 broad categories for analysis. The factors with the strongest correlation with dislocation included patient cognition, previous failed surgery, delay to surgery, surgical approach and femoral offset. CONCLUSION: Hip hemiarthroplasty remains the gold standard for elderly patients with intracapsular neck of femur fractures. In each individual case the factors most strongly associated with postoperative dislocation should be recognised. Delays to surgery should be minimised and the posterior approach avoided. In addition to good surgical technique, particular attention should be paid to restoring the patient's native femoral offset and post operatively those with cognitive impairment should be closely monitored.

The management of paediatric diaphyseal femoral fractures: a modern approach.

The definitive treatment of paediatric femoral diaphyseal fractures remains controversial. Modalities of treatment vary mostly according to age, with fracture pattern and site having a lesser impact. Current evidence is reflective of this variation with most evidence cited by the American Academy of Orthopedic Surgeons being level 4 or 5. The authors present a review of the most up-to-date evidence relating to the treatment of these fractures in each age group. In an attempt to clarify the current trends, we have produced an algorithm for decision-making based on the experience from our own tertiary referral level 1 major trauma centre.

The variability in the external rotation axis of the distal femur: an MRI-based anatomical study.

Commonly used total knee arthroplasty (TKA) systems utilising measured resection techniques default to 5°-7° valgus for the distal cut relative to the anatomical axis and 3° external rotation of the femoral component relative to posterior condylar axis (PCA). Rotational errors of the femoral component are associated with pain, patella maltracking and a poorer outcome. We analysed MRI scans from patients undergoing TKA using patient-specific instrumentation to assess coronal and rotational alignment from landmarks identified on the scans. One hundred and eight scans in 59 males and 49 females were studied with age range 35-93 years (mean 67.9 years). We found 91 % of patients had a femoral valgus angle between 5° and 7° (mean angles 5.9°), while only 24 % had an external rotation angle between 2.5° and 3.5° relative to PCA. There was no statistical significance in rotation between males and females although outliers tended to be female. Mean Whiteside's angle was 92.9° (87.8-98). This study highlights the variations in external rotation between patients undergoing TKA using the PCA as a reference for rotation. This may be a contributing factor in implant malalignment and patient dissatisfaction.

Detailed monitoring of a small but recovering population reveals sublethal effects of disease and unexpected interactions with supplemental feeding.

Infectious diseases are widely recognized to have substantial impact on wildlife populations. These impacts are sometimes exacerbated in small endangered populations, and therefore, the success of conservation reintroductions to aid the recovery of such species can be seriously threatened by outbreaks of infectious disease. Intensive management strategies associated with conservation reintroductions can further compound these negative effects in such populations. Exploring the sublethal effects of disease outbreaks among natural populations is challenging and requires longitudinal, individual life-history data on patterns of reproductive success and other indicators of individual fitness. Long-term monitoring data concerning detailed reproductive information of the reintroduced Mauritius parakeet (Psittacula echo) population collected before, during and after a disease outbreak was investigated. Deleterious effects of an outbreak of beak and feather disease virus (BFDV) were revealed on hatch success, but these effects were remarkably short-lived and disproportionately associated with breeding pairs which took supplemental food. Individual BFDV infection status was not predicted by any genetic, environmental or conservation management factors and was not associated with any of our measures of immune function, perhaps suggesting immunological impairment. Experimental immunostimulation using the PHA (phytohaemagglutinin assay) challenge technique did, however, provoke a significant cellular immune response. We illustrate the resilience of this bottlenecked and once critically endangered, island-endemic species to an epidemic outbreak of BFDV and highlight the value of systematic monitoring in revealing inconspicuous but nonetheless substantial ecological interactions. Our study demonstrates that the emergence of such an infectious disease in a population ordinarily associated with increased susceptibility does not necessarily lead to deleterious impacts on population growth and that negative effects on reproductive fitness can be short-lived.

Molecular identification of Ehrlichia species and host bloodmeal source in Amblyomma americanum L. from two locations in Tennessee, United States.

The current status of tick-borne diseases in the southeastern United States is challenging to define due to emerging pathogens, uncertain tick/host relationships, and changing disease case definitions. A golf-oriented retirement community on the Cumberland Plateau in Tennessee experienced an ehrlichiosis outbreak in 1993, prompting efforts to reduce the local tick population using '4-Poster' acaricide devices targeting white-tailed deer (Odocoileus virginianus). In 2009, the prevalence of Ehrlichia spp. in questing ticks was surveyed in the area and compared to a Tennessee state park where acaricide had not been applied. The range of wildlife hosts that immature Amblyomma americanum fed upon and the role that these hosts may play in pathogen dynamics were investigated using a reverse line blot (RLB) bloodmeal analysis technique. Amblyomma americanum was by far the most common tick species in both study areas (>99% of ticks collected). Of 303 adult and nymphal A. americanum tested at the retirement community, six were positive for Ehrlichia chaffeensis (2.0%), 16 were positive for E. ewingii (5.3%), and six were positive for Panola Mountain Ehrlichia (2.0%). This is the first confirmation of Panola Mountain Ehrlichia in A. americanum from the state of Tennessee. The 9.3% prevalence of Ehrlichia spp. in ticks from the retirement community was similar to that detected at the state park site (5.5%), suggesting that the 4-Poster treatment had not been sufficient to reduce Ehrlichia spp. cycling in the tick population. At both study sites, A. americanum fed on a wide range of mammal and bird species, with a minority of detectable bloodmeals coming from deer. Of the Ehrlichia-infected nymphs with positive bloodmeal identification, none fed on deer, indicating that multiple vertebrate species are contributing to sylvatic maintenance of Ehrlichia spp. at these sites. This highlights the difficulty of attempting to reduce the risk of tick-borne disease through host-targeted interventions alone.