SNAPSHOT USA 2021: A third coordinated national camera trap survey of the United States.

SNAPSHOT USA is a multicontributor, long-term camera trap survey designed to survey mammals across the United States. Participants are recruited through community networks and directly through a website application (https://www.snapshot-usa.org/). The growing Snapshot dataset is useful, for example, for tracking wildlife population responses to land use, land cover, and climate changes across spatial and temporal scales. Here we present the SNAPSHOT USA 2021 dataset, the third national camera trap survey across the US. Data were collected across 109 camera trap arrays and included 1711 camera sites. The total effort equaled 71,519 camera trap nights and resulted in 172,507 sequences of animal observations. Sampling effort varied among camera trap arrays, with a minimum of 126 camera trap nights, a maximum of 3355 nights, a median 546 nights, and a mean 656 ± 431 nights. This third dataset comprises 51 camera trap arrays that were surveyed during 2019, 2020, and 2021, along with 71 camera trap arrays that were surveyed in 2020 and 2021. All raw data and accompanying metadata are stored on Wildlife Insights (https://www.wildlifeinsights.org/), and are publicly available upon acceptance of the data papers. SNAPSHOT USA aims to sample multiple ecoregions in the United States with adequate representation of each ecoregion according to its relative size. Currently, the relative density of camera trap arrays varies by an order of magnitude for the various ecoregions (0.22-5.9 arrays per 100,000 km2), emphasizing the need to increase sampling effort by further recruiting and retaining contributors. There are no copyright restrictions on these data. We request that authors cite this paper when using these data, or a subset of these data, for publication. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government.

Guardians of the Genome: How the Single-Stranded DNA-Binding Proteins RPA and CST Facilitate Telomere Replication.

Telomeres act as the protective caps of eukaryotic linear chromosomes; thus, proper telomere maintenance is crucial for genome stability. Successful telomere replication is a cornerstone of telomere length regulation, but this process can be fraught due to the many intrinsic challenges telomeres pose to the replication machinery. In addition to the famous "end replication" problem due to the discontinuous nature of lagging strand synthesis, telomeres require various telomere-specific steps for maintaining the proper 3' overhang length. Bulk telomere replication also encounters its own difficulties as telomeres are prone to various forms of replication roadblocks. These roadblocks can result in an increase in replication stress that can cause replication forks to slow, stall, or become reversed. Ultimately, this leads to excess single-stranded DNA (ssDNA) that needs to be managed and protected for replication to continue and to prevent DNA damage and genome instability. RPA and CST are single-stranded DNA-binding protein complexes that play key roles in performing this task and help stabilize stalled forks for continued replication. The interplay between RPA and CST, their functions at telomeres during replication, and their specialized features for helping overcome replication stress at telomeres are the focus of this review.

Photographic documentation of melanism in bobcats (Lynx rufus) in the Greater Everglades.

We document the presence of bobcats (Lynx rufus) that demonstrate melanism in the Greater Everglades. The South Florida landscape is driven by a myriad of disturbance regimes particularly that of short fire intervals. We monitored 180 camera traps for 3 years and obtained 9503 photographs of bobcats 25 (<0.5%) of these detections included melanistic individuals. Our observations and historical accounts suggest melanism is a phenotype that persists, albeit it at an exceedingly low frequency, in bobcats in the region. While we do not know if the expression of melanism conferred a fitness benefit in our system, the vegetation structure that was characterized by frequently burned uplands and low-light and densely vegetated swamps produced conditions that may render a benefit from melanism through enhanced crypsis. The investigation of rare phenomenon in ecology is important yet difficult within a given field study, but reporting novel observations, like melanism in bobcats, allows for science to gain insight across studies that would not be otherwise possible.

Polychlorinated biphenyl (PCB) exposure in adult female mice can influence bladder contractility.

Lower urinary tract symptoms (LUTS) greatly reduce quality of life. While LUTS etiology is not completely understood, it is plausible that environmental contaminants could play a role. Polychlorinated biphenyls (PCBs), are a group of persistent environmental toxicants frequently documented in animal and human tissues. PCBs are capable of influencing voiding function in mouse offspring exposed developmentally, however whether PCB exposure during adulthood can also influence voiding dynamics is unknown. Therefore, the purpose of this study was to determine whether PCB exposure in adult female mice can impact voiding function. As part of a larger study to generate developmentally exposed offspring, adult female C57Bl/6J mice were dosed orally with the MARBLES PCB mixture (0.1, 1, or 6 mg/kg/day) or vehicle control beginning two weeks before mating and throughout gestation and lactation (9 weeks). Adult dosed female dams then underwent void spot assay, uroflowmetry, and anesthetized cystometry to assess voiding function. Bladder contractility was assessed in ex vivo bladder bath assays, and bladders were collected for morphology and histology assessments. While voiding behavior endpoints were minimally impacted, alterations to bladder contractility dynamics were more pronounced. Adult female mice dosed with 1 mg/kg/d PCB showed an increase in urine spots 2-3 cm2 in size, increased bladder contractility in response to electrical field stimulation, and decreased bladder wall thickness compared to vehicle control. PCBs also altered contractile response to cholinergic agonist in a dose-dependent manner. Overall, these results indicate that exposure to PCBs in adult female mice is sufficient to produce changes in bladder physiology. These results also highlight the critical role of timing of exposure in influencing voiding function.

Provider Perceptions of Oxygenation Strategies for Critically Ill Trauma Patients With and Without Moderate-to-Severe Traumatic Brain Injury.

BACKGROUND: Hypoxia and hyperoxia (pulse oximetry [SpO2] > 96%) are associated with increased mortality in critically ill patients. However, provider practices regarding oxygenation in traumatic brain injury (TBI) patients are unknown. This study assesses views on oxygenation of critically ill trauma patients with and without TBI and how this varies between Neurological ICU (NeuroICU) and Surgical-Trauma ICU (STICU) providers. METHODS: This is a cross-sectional survey of Level I trauma center's NeuroICU and STICU providers. We used Likert scales, yes-no questions, and multiple-choice case-based scenarios to characterize provider views on oxygenation with descriptive statistics to characterize responses. Significant differences regarding TBI and non-TBI patients or NeuroICU and STICU providers were determined using Fisher's exact test and a P-value of .05. RESULTS: A total of 83 providers initiated the survey, and 53 providers completed it. Most providers identified a threshold SpO2 < 92% for the administration of supplemental oxygen in critically ill TBI patients. A total of 9% of providers "somewhat or completely agreed" that they were more likely to give supplemental oxygen to a critically ill trauma patient with TBI than one without TBI and the same SpO2. A total of 48% of providers selected an SpO2 < 90% as the point at which supplemental oxygen should be initiated in patients without TBI, compared to 27% of providers in patients with TBI (P < .01). This threshold for supplemental oxygen use varied by provider type for non-TBI patients, but not for TBI patients (30% NeuroICU and 69% STICU providers selected SpO2 < 90% in non-TBI, P < .05; 30% NeuroICU and 35% STICU providers selected SpO2 < 90% in TBI, P = .85). CONCLUSIONS: Critical care providers at UCHealth University of Colorado Hospital approach the oxygenation of critically ill trauma patients with and without TBI differently. Specifically, critical care respondents accepted a different lower oxygen saturation threshold for TBI and non-TBI patients. NeuroICU and STICU respondents differed in their threshold for the down-titration of supplemental oxygen. Targeted education for critical care providers may reduce these discrepancies and optimize oxygen use.

Effects of Maternal HIV Infection on Early Kaposi Sarcoma-Associated Herpesvirus Seroconversion in a Kenyan Mother-Infant Cohort.

BACKGROUND: We identified whether maternal human immunodeficiency virus (HIV) infection during pregnancy affects transplacental transfer of Kaposi sarcoma-associated herpesvirus (KSHV)-specific antibodies and subsequent infant infection. METHODS: We followed pregnant Kenyan women through delivery and their infants until age 2 years. Children were classified as HIV-exposed uninfected (HEU) or HIV-unexposed uninfected (HUU) based on maternal HIV status. Maternal venous and cord blood at delivery and child venous blood every 6 months were tested for antibodies to 20 KSHV antigens by multiplex bead-based immunoassay. Multiple comparisons were adjusted using false discovery rate (FDR). RESULTS: Maternal HIV infection was significantly associated with decreased transplacental transfer of antibodies against all KSHV antigens and lower cord blood levels for 8 antigens at FDR P < .10. Neither birth to 6-month antibody level changes nor 6-month levels differed in HEU and HUU, except for ORF50. By age 24 months, 74% of children KSHV seroconverted but HEU and HUU did not differ in time to seroconversion nor 2-year seropositivity after adjustment for child malaria infection. CONCLUSIONS: Maternal HIV infection reduced a child's initial KSHV antibody levels but did not affect age of infection. Regardless of HIV exposure in utero, KSHV seroconversion in Kenyan children occurred early; associated factors must be identified.

Polychlorinated Biphenyls (PCBs) Impact Prostatic Collagen Density and Bladder Volume in Young Adult Mice Exposed during in Utero and Lactational Development.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants linked to deleterious health outcomes, including voiding dysfunction in developmentally exposed mice. Changes in prostate volume and/or extracellular matrix composition are associated with voiding dysfunction in men and animal models. Whether PCB-induced changes in voiding function in male mice occur in part via alterations to the prostate or an alternate mechanism is unclear. Therefore, we tested whether developmental exposure to the MARBLES PCB mixture altered prostate morphology in young adult offspring. C57Bl/6J female mice were dosed daily with the MARBLES PCB mixture at 0, 0.1, 1 or 6 mg/kg/d for two weeks prior to mating and through gestation and lactation, offspring were collected at 6 weeks of age. Ventral prostate mass was decreased in the 1 mg/kg/d PCB group compared to other PCB groups. There were no PCB-induced changes in prostate smooth muscle thickness, apoptosis, proliferation, or testes mass. PCBs impacted the prostate extracellular matrix; anterior prostate collagen density was decreased in the 1 mg/kg/d PCB group compared to all other groups. Normalized bladder volume was increased in male and female offspring in the 6 mg/kg/d PCB group compared to control. No change in water consumption, bladder mass or bladder smooth muscle thickness accompanied changes in bladder volume. Urine and serum creatinine concentrations were elevated but only in male mice. Together, these results suggest that developmental exposure to PCBs can influence prostate wet weight and prostate/bladder morphology, but PCBs do not promote prostate enlargement. Whether these changes persist throughout adult life and how they contribute to voiding function in animal models and humans is of future interest.

Rain, recreation and risk: Human activity and ecological disturbance create seasonal risk landscapes for the prey of an ambush predator.

Predation risk and prey responses exhibit fluctuations in space and time. Seasonal ecological disturbances can alter landscape structure and permeability to influence predator activity and efficacy, creating predictable patterns of risk for prey (seasonal risk landscapes). This may create corresponding seasonal shifts in antipredator behaviour, mediated by species ecology and trade-offs between risk and resources. Yet, how human recreation interacts with seasonal risk landscapes and antipredator behaviour remains understudied. In South Florida, we investigated the impact of a seasonal ecological disturbance, specifically flooding, which is inversely related to human activity, on interactions between Florida panthers (Puma concolor coryi) and white-tailed deer (Odocoileus virginianus). We hypothesized that human activity and ecological disturbances would interact with panther-deer ecology, resulting in the emergence of two distinct seasonal landscapes of predation risk and the corresponding antipredator responses. We conducted camera trap surveys across southwestern Florida to collect detection data on humans, panthers and deer. We analysed the influence of human site use and flooding on deer and panther detection probability, co-occurrence and diel activity during the flooded and dry seasons. Flooding led to decreased panther detections and increased deer detections, resulting in reduced deer-panther co-occurrence during the flooded season. Panthers exhibited increased nocturnality and reduced diel activity overlap with deer in areas with higher human activity. Supporting our hypothesis, panthers' avoidance of human recreation and flooding created distinct risk schedules for deer, driving their antipredator behaviour. Deer utilized flooded areas to spatially offset predation risk during the flooded season while increasing diurnal activity in response to human recreation during the dry season. We highlight the importance of understanding how competing risks and ecological disturbances influence predator and prey behaviour, leading to the generation of seasonal risk landscapes and antipredator responses. We emphasize the role of cyclical ecological disturbances in shaping dynamic predator-prey interactions. Furthermore, we highlight how human recreation may function as a 'temporal human shield,' altering seasonal risk landscapes and antipredator responses to reduce encounter rates between predators and prey.

Advances in stem cell and other therapies for Huntington's disease: An update.

Huntington's disease (HD) is a neurodegenerative disorder caused by an autosomal dominant mutation leading to an abnormal CAG repeat expansion. The result is the synthesis of a toxic misfolded protein, called the mutant huntingtin protein (mHTT). Most current treatments are palliative, but the latest research has expanded into multiple modalities, including stem cells, gene therapy, and even the use of 3D cell structures, called organoids. Stem cell research as a treatment for HD has included the use of various types of stem cells, such as mesenchymal stem cells, neural stem cells, embryonic stem cells, and even reprogrammed stem cells called induced pluripotent stem cells. The goal has been to develop stem cell transplant grafts that will replace the existing mutated neurons, as well as release existing trophic factors for neuronal support. Additionally, research in gene modification using CRISPR-Cas9, PRIME editing, and other forms of genetic modifications are continuing to evolve. Most recently, advancements in stem cell modeling have yielded 3D stem cell tissue models, called organoids. These organoids offer the unique opportunity to transplant a structured stem cell graft which, ideally, models normal human brain tissue more accurately. This manuscript summarizes the recent research in stem cells, genetic modifications, and organoids as a potential for treatment of HD.

Evidence for Aerosol Transfer of SARS-CoV-2-Specific Humoral Immunity.

Infectious particles can be shared through aerosols and droplets formed as the result of normal respiration. Whether Abs within the nasal/oral fluids can similarly be shared between hosts has not been investigated. The circumstances of the SARS-CoV-2 pandemic facilitated a unique opportunity to fully examine this provocative idea. The data we show from human nasal swabs provides evidence for the aerosol transfer of Abs between immune and nonimmune hosts.

RPA engages telomeric G-quadruplexes more effectively than CST.

G-quadruplexes (G4s) are a set of stable secondary structures that form within guanine-rich regions of single-stranded nucleic acids that pose challenges for DNA maintenance. The G-rich DNA sequence at telomeres has a propensity to form G4s of various topologies. The human protein complexes Replication Protein A (RPA) and CTC1-STN1-TEN1 (CST) are implicated in managing G4s at telomeres, leading to DNA unfolding and allowing telomere replication to proceed. Here, we use fluorescence anisotropy equilibrium binding measurements to determine the ability of these proteins to bind various telomeric G4s. We find that the ability of CST to specifically bind G-rich ssDNA is substantially inhibited by the presence of G4s. In contrast, RPA tightly binds telomeric G4s, showing negligible changes in affinity for G4 structure compared to linear ssDNAs. Using a mutagenesis strategy, we found that RPA DNA-binding domains work together for G4 binding, and simultaneous disruption of these domains reduces the affinity of RPA for G4 ssDNA. The relative inability of CST to disrupt G4s, combined with the greater cellular abundance of RPA, suggests that RPA could act as a primary protein complex responsible for resolving G4s at telomeres.

Hyperoxia is associated with a greater risk for mortality in critically ill traumatic brain injury patients than in critically ill trauma patients without brain injury.

OBJECTIVE: The role of hyperoxia in patients with traumatic brain injury (TBI) remains controversial. The objective of this study was to determine the association between hyperoxia and mortality in critically ill TBI patients compared to critically ill trauma patients without TBI. DESIGN: Secondary analysis of a multicenter retrospective cohort study. SETTING: Three regional trauma centers in Colorado, USA, between October 1, 2015, and June 30, 2018. PATIENTS: We included 3464 critically injured adults who were admitted to an intensive care unit (ICU) within 24 h of arrival and qualified for inclusion into the state trauma registry. We analyzed all available SpO2 values during the first seven ICU days. The primary outcome was in-hospital mortality. Secondary outcomes included the proportion of time spent in hyperoxia (defined as SpO2 > 96%) and ventilator-free days. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In-hospital mortality occurred in 163 patients (10.7%) in the TBI group and 101 patients (5.2%) in the non-TBI group. After adjusting for ICU length of stay, TBI patients spent a significantly greater amount of time in hyperoxia versus non-TBI patients (p = 0.024). TBI status significantly modified the effect of hyperoxia on mortality. At each specific SpO2 level, the risk of mortality increases with increasing FiO2 for both patients with and without TBI. This trend was more pronounced at lower FiO2 and higher SpO2 values, where a greater number of patient observations were obtained. Among patients who required invasive mechanical ventilation, TBI patients required significantly more days of ventilation to day 28 than non-TBI patients. CONCLUSIONS: Critically ill trauma patients with a TBI spend a greater proportion of time in hyperoxia compared to those without a TBI. TBI status significantly modified the effect of hyperoxia on mortality. Prospective clinical trials are needed to better assess a possible causal relationship.

Repeat Ivermectin Mass Drug Administrations for Malaria Control II: Protocol for a Double-blind, Cluster-Randomized, Placebo-Controlled Trial for the Integrated Control of Malaria.

BACKGROUND: The gains made against malaria have stagnated since 2015, threatened further by increasing resistance to insecticides and antimalarials. Improvement in malaria control necessitates a multipronged strategy, which includes the development of novel tools. One such tool is mass drug administration (MDA) with endectocides, primarily ivermectin, which has shown promise in reducing malaria transmission through lethal and sublethal impacts on the mosquito vector. OBJECTIVE: The primary objective of the study is to assess the impact of repeated ivermectin MDA on malaria incidence in children aged ≤10 years. METHODS: Repeat Ivermectin MDA for Malaria Control II is a double-blind, placebo-controlled, cluster-randomized, and parallel-group trial conducted in a setting with intense seasonal malaria transmission in Southwest Burkina Faso. The study included 14 discrete villages: 7 (50%) randomized to receive standard measures (seasonal malaria chemoprevention [SMC] and bed net use for children aged 3 to 59 months) and placebo, and 7 (50%) randomized to receive standard measures and monthly ivermectin MDA at 300 µg/kg for 3 consecutive days, provided under supervision to all eligible village inhabitants, over 2 successive rainy seasons. Nonpregnant individuals >90 cm in height were eligible for ivermectin MDA, and cotreatment with ivermectin and SMC was not permitted. The primary outcome is malaria incidence in children aged ≤10 years, as assessed by active case surveillance. The secondary safety outcome of repeated ivermectin MDA was assessed through active and passive adverse event monitoring. RESULTS: The trial intervention was conducted from July to November in 2019 and 2020, with additional sampling of humans and mosquitoes occurring through February 2022 to assess postintervention changes in transmission patterns. Additional human and entomological assessments were performed over the 2 years in a subset of households from 6 cross-sectional villages. A subset of individuals underwent additional sampling in 2020 to characterize ivermectin pharmacokinetics and pharmacodynamics. Analysis and unblinding will commence once the database has been completed, cleaned, and locked. CONCLUSIONS: Our trial represents the first study to directly assess the impact of a novel approach for malaria control, ivermectin MDA as a mosquitocidal agent, layered into existing standard-of-care interventions. The study was designed to leverage the current SMC deployment infrastructure and will provide evidence regarding the additional benefit of ivermectin MDA in reducing malaria incidence in children. TRIAL REGISTRATIONS: ClinicalTrials.gov NCT03967054; https://clinicaltrials.gov/ct2/show/NCT03967054 and Pan African Clinical Trials Registry PACT201907479787308; https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=8219. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/41197.

Prey species increase activity in refugia free of terrestrial predators.

The decline of terrestrial predator populations across the globe is altering top-down pressures that drive predator-prey interactions. However, a knowledge gap remains in understanding how removing terrestrial predators affects prey behavior. Using a bifactorial playback experiment, we exposed fox squirrels to predator (red-tailed hawks, coyotes, dogs) and non-predator control (Carolina wren) calls inside terrestrial predator exclosures, accessible to avian predators, and in control areas subject to ambient predation risk. Fox squirrels increased their use of terrestrial predator exclosures, a pattern that corresponded with 3 years of camera trapping. Our findings suggest fox squirrels recognized that exclosures had predictably lower predation risk. However, exclosures had no effect on their immediate behavioral response towards any call, and fox squirrels responded most severely to hawk predator calls. This study shows that anthropogenically driven predator loss creates predictably safer areas (refugia) that prey respond to proactively with increased use. However, the persistence of a lethal avian predator is sufficient to retain a reactive antipredator response towards an immediate predation threat. Some prey may benefit from shifting predator-prey interactions by gaining refugia without sacrificing a sufficient response towards potential predators.

ED-based COVID-19 vaccination campaign finds higher vaccination rates for individuals from racial and ethnic minority groups compared with clinic setting.

BACKGROUND: Emergency department visits associated with Coronavirus Disease 2019 (COVID-19) continue to indicate racial and ethnic inequities. We describe the sociodemographic characteristics of individuals receiving COVID-19 vaccination in the emergency department and compare with an outpatient clinic population and emergency department (ED) patients who were eligible but not vaccinated. METHODS: We conducted a retrospective analysis of electronic health record data at an urban academic ED from May to July 2021. The primary aim was to characterize the ED-vaccinated population, compared with ED patients who were eligible but unvaccinated and the physically adjacent outpatient vaccination clinic population. RESULTS: A total of 627 COVID-19 vaccinations were administered in the ED. Overall, 49% of ED patients during that time had already received at least one vaccine dose prior to ED arrival. Hispanic, non-Hispanic Black patients, and patients on non-commercial insurance had higher odds of being vaccinated in the ED as compared with outpatient clinic setting. Among eligible ED patients, men and patients who were uninsured/self-pay were more likely to accept ED vaccination. CONCLUSIONS: This ED COVID-19 vaccination campaign demonstrated a higher likelihood to vaccinate individuals from racial/ethnic minority groups, those with high social vulnerability, and non-commercial insurance, when compared with a co-located outpatient vaccination clinic.

Season and prey identity mediate the effect of predators on parasites in rodents: a test of the healthy herds hypothesis.

The healthy herds hypothesis (HHH) suggests that predators decrease parasitism in their prey. Repeated tests of this hypothesis across a range of taxa and ecosystems have revealed significant variation in the effect of predators on parasites in prey. Differences in the response to predators (1) between prey taxa, (2) between seasons, and (3) before and after catastrophic disturbance are common in natural systems, but typically ignored in empirical tests of the HHH. We used a predator exclusion experiment to measure the effect of these heterogeneities on the tri-trophic interaction among predators, parasites and prey. We experimentally excluded mammalian predators from the habitats of hispid cotton rats (Sigmodon hispidus) and cotton mice (Peromyscus gossypinus) and measured the effect of exclusion on gastrointestinal parasites in these rodents. Our experiment spanned multiple seasons and before and after a prescribed burn. We found that the exclusion of the same predators had opposite effects on the parasites of small mammal prey species. Additionally, we found that the effect of mammal exclusion on parasitism differed before versus after fire disturbance. Finally, we saw that the effect of predator exclusion was highly dependent on prey capture season. Significant effects of exclusion emerged primarily in the fall and winter months. The presence of so many different effects in one relatively simple system suggests that predator effects on parasites in prey are highly context dependent.

Evolution of the Gut Microbiome in HIV-Exposed Uninfected and Unexposed Infants during the First Year of Life.

HIV-exposed uninfected infants (HEU) have abnormal immunologic functions and increased infectious morbidity in the first 6 months of life, which gradually decreases thereafter. The mechanisms underlying HEU immune dysfunctions are unknown. We hypothesized that unique characteristics of the HEU gut microbiota associated with maternal HIV status may underlie the HEU immunologic dysfunctions. We characterized the infant gut, maternal gut, and breast milk microbiomes of mother-infant pairs, including 123 with HEU and 117 with HIV-uninfected infants (HUU), from South Africa. Pan-bacterial 16S rRNA gene sequencing was performed on (i) infant stool at 6, 28, and 62 weeks; (ii) maternal stool at delivery and 62 weeks; and (iii) breast milk at 6 weeks. Infant gut alpha and beta diversities were similar between groups. Microbial composition significantly differed, including 12 genera, 5 families and 1 phylum at 6 weeks; 12 genera and 2 families at 28 weeks; and 2 genera and 2 families at 62 weeks of life. Maternal gut microbiomes significantly differed in beta diversity and microbial composition, and breast milk microbiomes differed in microbial composition only. Infant gut microbiotas extensively overlapped with maternal gut and minimally with breast milk microbiotas. Nevertheless, exclusively breastfed HEU and HUU had less divergent microbiomes than nonexclusively breastfed infants. Feeding pattern and maternal gut microbiome imprint the HEU gut microbiome. Compared to HUU, the HEU gut microbiome prominently differs in early infancy, including increased abundance of taxa previously observed to be present in excess in adults with HIV. The HEU and HUU gut microbiome compositions converge over time, mirroring the kinetics of HEU infectious morbidity risk. IMPORTANCE HIV-exposed uninfected infants (HEU) are highly vulnerable to infections in the first 6 months of life, and this vulnerability decreases to the age of 24 months. Because the microbiome plays a critical role in the education of the infant immune system, which protects them against infections, we characterized the gut microbiomes of HEU and HIV-unexposed infants (HUU) in the first year of life. The HEU and HUU gut microbiomes showed prominent differences at 6 and 28 weeks of life but converged at 62 weeks of life, mirroring the time course of the HEU excess infectious morbidity and suggesting a potential association between the infant gut microbiome structure and susceptibility to infections. Infant gut microbiotas extensively overlapped with maternal gut and minimally with breast milk microbiotas. Moreover, exclusively breastfed HEU and HUU had less divergent microbiomes at 6 and 28 weeks than nonexclusively breastfed HEU and HUU. The factors that affect the HEU gut microbiome, maternal gut microbiome and exclusive breastfeeding, may be targeted by interventions.

Developmental polychlorinated biphenyl (PCB) exposure alters voiding physiology in young adult male and female mice.

The impact of developmental exposure to environmental chemicals on lower urinary tract function is not well understood, despite the fact that these chemicals could contribute to etiologically complex lower urinary tract symptoms (LUTS). Polychlorinated biphenyls (PCBs) are environmental toxicants known to be detrimental to the central nervous system, but their impact on voiding function in mouse models is not known. Therefore, we test whether developmental exposure to PCBs is capable of altering voiding physiology in young adult mice. C57Bl/6J female mice received a daily oral dose of the MARBLES PCB mixture for two weeks prior to mating and through gestation and lactation. The mixture mimics the profile of PCBs found in a contemporary population of pregnant women. Voiding function was then tested in young adult offspring using void spot assay, uroflowmetry and anesthetized cystometry. PCB effects were sex and dose dependent. Overall, PCBs led to increases in small size urine spots in both sexes with males producing more drop-like voids and greater peak pressure during a voiding cycle while females displayed decreases in void duration and intervoid interval. Together, these results indicate that developmental exposure to PCBs are capable of altering voiding physiology in young adult mice. Further work to identify the underlying mechanisms driving these changes may help develop more effective preventative or therapeutic strategies for LUTS.

Fire as a driver and mediator of predator-prey interactions.

Both fire and predators have strong influences on the population dynamics and behaviour of animals, and the effects of predators may either be strengthened or weakened by fire. However, knowledge of how fire drives or mediates predator-prey interactions is fragmented and has not been synthesised. Here, we review and synthesise knowledge of how fire influences predator and prey behaviour and interactions. We develop a conceptual model based on predator-prey theory and empirical examples to address four key questions: (i) how and why do predators respond to fire; (ii) how and why does prey vulnerability change post-fire; (iii) what mechanisms do prey use to reduce predation risk post-fire; and (iv) what are the outcomes of predator-fire interactions for prey populations? We then discuss these findings in the context of wildlife conservation and ecosystem management before outlining priorities for future research. Fire-induced changes in vegetation structure, resource availability, and animal behaviour influence predator-prey encounter rates, the amount of time prey are vulnerable during an encounter, and the conditional probability of prey death given an encounter. How a predator responds to fire depends on fire characteristics (e.g. season, severity), their hunting behaviour (ambush or pursuit predator), movement behaviour, territoriality, and intra-guild dynamics. Prey species that rely on habitat structure for avoiding predation often experience increased predation rates and lower survival in recently burnt areas. By contrast, some prey species benefit from the opening up of habitat after fire because it makes it easier to detect predators and to modify their behaviour appropriately. Reduced prey body condition after fire can increase predation risk either through impaired ability to escape predators, or increased need to forage in risky areas due to being energetically stressed. To reduce risk of predation in the post-fire environment, prey may change their habitat use, increase sheltering behaviour, change their movement behaviour, or use camouflage through cryptic colouring and background matching. Field experiments and population viability modelling show instances where fire either amplifies or does not amplify the impacts of predators on prey populations, and vice versa. In some instances, intense and sustained post-fire predation may lead to local extinctions of prey populations. Human disruption of fire regimes is impacting faunal communities, with consequences for predator and prey behaviour and population dynamics. Key areas for future research include: capturing data continuously before, during and after fires; teasing out the relative importance of changes in visibility and shelter availability in different contexts; documenting changes in acoustic and olfactory cues for both predators and prey; addressing taxonomic and geographic biases in the literature; and predicting and testing how changes in fire-regime characteristics reshape predator-prey interactions. Understanding and managing the consequences for predator-prey communities will be critical for effective ecosystem management and species conservation in this era of global change.