Marine heatwave and reduced light scenarios cause species-specific metabolomic changes in seagrasses under ocean warming.

Climate change and extreme climatic events, such as marine heatwaves (MHWs), are threatening seagrass ecosystems. Metabolomics can be used to gain insight into early stress responses in seagrasses and help to develop targeted management and conservation measures. We used metabolomics to understand the temporal and mechanistic response of leaf metabolism in seagrasses to climate change. Two species, temperate Posidonia australis and tropical Halodule uninervis, were exposed to a combination of future warming, simulated MHW with subsequent recovery period, and light deprivation in a mesocosm experiment. The leaf metabolome of P. australis was altered under MHW exposure at ambient light while H. uninervis was unaffected. Light deprivation impacted both seagrasses, with combined effects of heat and low light causing greater alterations in leaf metabolism. There was no MHW recovery in P. australis. Conversely, the heat-resistant leaf metabolome of H. uninervis showed recovery of sugars and intermediates of the tricarboxylic acid cycle under combined heat and low light exposure, suggesting adaptive strategies to long-term light deprivation. Overall, this research highlights how metabolomics can be used to study the metabolic pathways of seagrasses, identifies early indicators of environmental stress and analyses the effects of environmental factors on plant metabolism and health.

Untargeted, High-Resolution Metabolomics in Pediatric Eosinophilic Esophagitis.

BACKGROUND/OBJECTIVES: Eosinophilic esophagitis (EoE) is an inflammatory disease of unclear etiology. The aim of this study was to use untargeted plasma metabolomics to identify metabolic pathway alterations associated with EoE to better understand the pathophysiology. METHODS: This prospective, case-control study included 72 children, aged 1-17 years, undergoing clinically indicated upper endoscopy (14 diagnosed with EoE and 58 controls). Fasting plasma samples were analyzed for metabolomics by high-resolution dual-chromatography mass spectrometry. Analysis was performed on sex-matched groups at a 2:1 ratio. Significant differences among the plasma metabolite features between children with and without EoE were determined using multivariate regression analysis and were annotated with a network-based algorithm. Subsequent pathway enrichment analysis was performed. RESULTS: Patients with EoE had a higher proportion of atopic disease (85.7% vs 50%, P = 0.019) and any allergies (100% vs 57.1%, P = 0.0005). Analysis of the dual chromatography features resulted in a total of 918 metabolites that differentiated EoE and controls. Glycerophospholipid metabolism was significantly enriched with the greatest number of differentiating metabolites and overall pathway enrichment ( P < 0.01). Multiple amino and fatty acid pathways including linoleic acid were also enriched, as well as pyridoxine metabolism ( P < 0.01). CONCLUSIONS: In this pilot study, we found differences in metabolites involved in glycerophospholipid and inflammation pathways in pediatric patients with EoE using untargeted metabolomics, as well as overlap with amino acid metabolome alterations found in atopic disease.

Single-Center Retrospective Review of the Presentation and Initial Care of Esophageal Button Battery Impactions 2007-2020.

OBJECTIVE: The aims of this study were to characterize the patient population and initial presentation and care of esophageal button battery ingestion and provide descriptive data including factors affecting accurate diagnosis, duration of battery exposure, and battery removal. METHODS: This was a retrospective cohort study from 2007 to 2020 at a single-center, large-volume, urban academic pediatric hospital system. Included participants were children 6 months to 18 years old who underwent removal of an esophageal button battery impaction at our institution. RESULTS: Our cohort comprised 63 patients; ages ranged from 7 to 87 months with a median of 27 months. Median button battery size was 2.12 cm with 59% lodged in the proximal esophagus. A prolonged impaction, greater than 12 hours, occurred in 46% of patients. Risk ratio analysis demonstrated that lack of caregiver suspicion of ingestion was associated with prolonged impaction (risk ratio, 3.39; confidence interval, 2.15-5.34). Misdiagnosis of button battery ingestion occurred in 10% of cases. The majority of patients, 87%, required transfer from a referring facility with a median total distance of 37 miles (range, 1.4-160 miles) from home to facility where battery was removed. CONCLUSION AND RELEVANCE: This study describes the initial presentation and care of a large cohort of pediatric esophageal button battery ingestion. It emphasizes the continued need for primary prevention, prompt identification, and removal of these batteries. There are many challenges in caring for these patients involving multiple pediatric disciplines, and guidelines encompassing a multidisciplinary approach would be beneficial.

Profiling the cell walls of seagrasses from A (Amphibolis) to Z (Zostera).

BACKGROUND: The polyphyletic group of seagrasses shows an evolutionary history from early monocotyledonous land plants to the marine environment. Seagrasses form important coastal ecosystems worldwide and large amounts of seagrass detritus washed on beaches might also be valuable bioeconomical resources. Despite this importance and potential, little is known about adaptation of these angiosperms to the marine environment and their cell walls. RESULTS: We investigated polysaccharide composition of nine seagrass species from the Mediterranean, Red Sea and eastern Indian Ocean. Sequential extraction revealed a similar seagrass cell wall polysaccharide composition to terrestrial angiosperms: arabinogalactans, pectins and different hemicelluloses, especially xylans and/or xyloglucans. However, the pectic fractions were characterized by the monosaccharide apiose, suggesting unusual apiogalacturonans are a common feature of seagrass cell walls. Detailed analyses of four representative species identified differences between organs and species in their constituent monosaccharide composition and lignin content and structure. Rhizomes were richer in glucosyl units compared to leaves and roots. Enhalus had high apiosyl and arabinosyl abundance, while two Australian species of Amphibolis and Posidonia, were characterized by high amounts of xylosyl residues. Interestingly, the latter two species contained appreciable amounts of lignin, especially in roots and rhizomes whereas Zostera and Enhalus were lignin-free. Lignin structure in Amphibolis was characterized by a higher syringyl content compared to that of Posidonia. CONCLUSIONS: Our investigations give a first comprehensive overview on cell wall composition across seagrass families, which will help understanding adaptation to a marine environment in the evolutionary context and evaluating the potential of seagrass in biorefinery incentives.

Extensive polyploid clonality was a successful strategy for seagrass to expand into a newly submerged environment.

Polyploidy has the potential to allow organisms to outcompete their diploid progenitor(s) and occupy new environments. Shark Bay, Western Australia, is a World Heritage Area dominated by temperate seagrass meadows including Poseidon's ribbon weed, Posidonia australis. This seagrass is at the northern extent of its natural geographic range and experiences extremes in temperature and salinity. Our genomic and cytogenetic assessments of 10 meadows identified geographically restricted, diploid clones (2n = 20) in a single location, and a single widespread, high-heterozygosity, polyploid clone (2n = 40) in all other locations. The polyploid clone spanned at least 180 km, making it the largest known example of a clone in any environment on earth. Whole-genome duplication through polyploidy, combined with clonality, may have provided the mechanism for P. australis to expand into new habitats and adapt to new environments that became increasingly stressful for its diploid progenitor(s). The new polyploid clone probably formed in shallow waters after the inundation of Shark Bay less than 8500 years ago and subsequently expanded via vegetative growth into newly submerged habitats.

Comparing Eosinophilic Esophagitis in a Black and Non-Black Pediatric Cohort.

OBJECTIVES: To compare presenting symptoms, comorbidities, disease, and treatment characteristics of a black pediatric eosinophilic esophagitis (EoE) group to a non-black pediatric EoE group. METHODS: A retrospective chart review consisting of pediatric patients diagnosed with EoE between the years of 2010 and 2018 at a single urban pediatric hospital system comprising 143 black pediatric patients compared with 142 non-black pediatric patients with similar distribution of age and sex. RESULTS: Both groups were majority male, and the median age of diagnosis between the black and non-black group was 5.1 and 6.7 years old, respectively. Comorbidities more commonly seen in the black group included food allergies, atopic dermatitis, asthma, and allergic rhinitis. Black patients were more likely to present with failure to thrive (FTT)/poor growth, whereas non-black patients were more likely to present with abdominal pain. There was no statistically significant difference between the groups in achieving remission using current therapies. The black group had higher rates of nonadherence to medical therapies. CONCLUSIONS: This is the largest study to date comparing a black versus non-black pediatric EoE population. The black population had more atopic comorbidities and FTT at presentation and had significantly more issues with nonadherence. This new knowledge describing EoE in a minority population will hopefully improve awareness, diagnosis, and management of EoE in this population.

Evolving Clinical Care in Esophageal Button Batteries: Impact of Expert-Opinion Guideline Adoption and Continued Gaps in Care.

BACKGROUND/OBJECTIVES: Esophageal button battery impactions (BBI) in children pose a significant danger to children. Although there are expert-opinion guidelines to help manage this population, few studies detail the impact of guidelines on the clinical care of these patients. With this study, we aimed to describe the care of these patients before and following adoption of guidelines at a single center. METHODS: Retrospective cohort study of patients with esophageal BBI at a single center, large volume, urban academic pediatric hospital system before adoption of expert-opinion guidelines (2007-2017) and following adoption (2018-2020). RESULTS: Cohort was comprised of 31 patients before adoption and 32 patients following adoption of guidelines. Patient characteristics did not differ between groups. After 2018, significantly more patients received acetic acid irrigation, initial cross-sectional imaging, and serial cross-sectional imaging. There was also an increase in intensive care unit (ICU) stays, number of intubations, nil per os time, and hospital length of stay. There was no difference in patient outcomes. CONCLUSION: This study describes a large cohort of pediatric esophageal BBI before and following adoption of guidelines. Findings detail increased adherence to guidelines resulting in more cross-sectional imaging which led to ICU stays, longer length of stays, and more nil per os time. This study emphasizes the need for multi-disciplinary guidelines as well as further multi-institutional study.

Management of esophageal button battery ingestions: resource utilization and outcomes.

PURPOSE: Institutions are adopting the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) guidelines for pediatric esophageal button battery ingestion (EBBI). Our objective was to evaluate the guidelines' impact on in-hospital resource utilization and short-term clinical outcomes in hemodynamically stable patients after endoscopic battery removal. METHODS: A single-center retrospective review of all EBBI admissions from 2010 to 2020. Patients were divided into two groups based on adoption of national guidelines: pre-guideline (2010-2015) and post-guideline (2016-2020). RESULTS: Sixty-five patients were studied (pre-guideline n = 23; post-guideline n = 42). Compared with pre-guideline, post-guideline use of magnetic resonance imaging (MRI) increased (2/23 [8.7%]; 30/42 [71.4%]; p < 0.001). Post-guideline increases resulted for median days (IQR) receiving antibiotics (0 [0, 4]; 6 [3, 8]; p = 0.01), total pediatric intensive care unit admission (0 [0, 1]; 3 [0, 6]; p < 0.001), and total hospital length of stay (5 [2, 11]; 11.5 [4, 17]; p = 0.02). Two patients in the post-guideline group had delayed presentations despite normal imaging: one with TEF and one with aorto-esophageal fistula. All survived to discharge. CONCLUSION: In EBBI cases managed using the consensus based NASPHAGN guidelines, we report increased resource utilization without improved patient outcomes. Further research should evaluate post-guideline costs and resource utilization.

Impact of Antiretroviral Therapy Duration on HIV-1 Infection of T Cells within Anatomic Sites.

Understanding the impact of antiretroviral therapy (ART) duration on HIV-infected cells is critical for developing successful curative strategies. To address this issue, we conducted a cross-sectional/inter-participant genetic characterization of HIV-1 RNA from pre- and on-therapy plasmas and HIV-1 DNA from CD4+ T cell subsets derived from peripheral blood (PB), lymph node (LN), and gut tissues of 26 participants after 3 to 17.8 years of ART. Our studies revealed in four acute/early participants who had paired PB and LN samples a substantial reduction in the proportion of HIV-infected cells per year on therapy within the LN. Extrapolation to all 12 acute/early participants estimated a much smaller reduction in the proportion of HIV-1-infected cells within LNs per year on therapy that was similar to that in the participants treated during chronic infection. LN-derived effector memory T (TEM) cells contained HIV-1 DNA that was genetically identical to viral sequences derived from pre- and on-therapy plasma samples. The proportion of identical HIV-1 DNA sequences increased within PB-derived TEM cells. However, the infection frequency of TEM cells in PB was stable, indicating that cellular proliferation that compensates for T cell loss over time contributes to HIV-1 persistence. This study suggests that ART reduces HIV-infected T cells and that clonal expansion of HIV-infected cells maintains viral persistence. Importantly, LN-derived TEM cells are a probable source of HIV-1 genomes capable of producing infectious HIV-1 and should be targeted by future curative strategies.IMPORTANCE HIV-1 persists as an integrated genome in CD4+ memory T cells during effective therapy, and cessation of current treatments results in resumption of viral replication. To date, the impact of antiretroviral therapy duration on HIV-infected CD4+ T cells and the mechanisms of viral persistence in different anatomic sites is not clearly elucidated. In the current study, we found that treatment duration was associated with a reduction in HIV-infected T cells. Our genetic analyses revealed that CD4+ effector memory T (TEM) cells derived from the lymph node appeared to contain provirus that was genetically identical to plasma-derived virions. Moreover, we found that cellular proliferation counterbalanced the decay of HIV-infected cells throughout therapy. The contribution of cellular proliferation to viral persistence is particularly significant in TEM cells. Our study emphasizes the importance of HIV-1 intervention and provides new insights into the location of memory T cells infected with HIV-1 DNA, which is capable of contributing to viremia.

Physical activity assessment among men undergoing genetic counseling for inherited prostate cancer: a teachable moment for improved survivorship.

BACKGROUND: Genetic counseling (GC) presents an opportunity to address modifiable cancer risk factors, such as obesity, which is impacted by non-adherence to physical activity (PA) guidelines. Adherence to PA guidelines has not been assessed among men undergoing GC for prostate cancer (PCA). We conducted a targeted analysis of men undergoing PCA GC to assess adherence to PA recommendations. METHODS: Using a cross-sectional design, a total of 158 men from the Genetic Evaluation of Men (GEM) study at two academic cancer centers with a diagnosis or at risk for PCA completed a structured lifestyle survey, including questions about the number of days and intensity of PA over the past year. One-sample t tests assessed adherence of participants to PA recommendations. Chi-square analyses compared differences in PA adherence by PCA status, aggressiveness, family history, and body mass index. Logistic regression analyses identified predictors of PA adherence. RESULTS: High proportions of GEM participants were overweight (44.9%) or obese (38.0%, p = 0.002). Men with PCA engaged in less moderate (p = 0.019) and vigorous (p = 0.005) aerobic activity than men without PCA. Higher education was predictive of adherence to light (p = 0.008), moderate (p = 0.019), and vigorous (p = 0.002) intensity PA. Older age (p = 0.015) and higher education (p = 0.001) were predictive of adherence to strength-based recommendations. CONCLUSIONS: High proportions of men receiving PCA GC were overweight/obese and lacked adherence to PA recommendations. GC represents a teachable moment to address PA to reduce cancer risk and promote cancer survivorship.

Human Immunodeficiency Virus (HIV)-Infected CCR6+ Rectal CD4+ T Cells and HIV Persistence On Antiretroviral Therapy.

BACKGROUND: Identifying where human immunodeficiency virus (HIV) persists in people living with HIV and receiving antiretroviral therapy is critical to develop cure strategies. We assessed the relationship of HIV persistence to expression of chemokine receptors and their chemokines in blood (n = 48) and in rectal (n = 20) and lymph node (LN; n = 8) tissue collected from people living with HIV who were receiving suppressive antiretroviral therapy. METHODS: Cell-associated integrated HIV DNA, unspliced HIV RNA, and chemokine messenger RNA were quantified by quantitative polymerase chain reaction. Chemokine receptor expression on CD4+ T cells was determined using flow cytometry. RESULTS: Integrated HIV DNA levels in CD4+ T cells, CCR6+CXCR3+ memory CD4+ T-cell frequency, and CCL20 expression (ligand for CCR6) were highest in rectal tissue, where HIV-infected CCR6+ T cells accounted for nearly all infected cells (median, 89.7%). Conversely in LN tissue, CCR6+ T cells were infrequent, and there was a statistically significant association of cell-associated HIV DNA and RNA with CCL19, CCL21, and CXCL13 chemokines. CONCLUSIONS: HIV-infected CCR6+ CD4+ T cells accounted for the majority of infected cells in rectal tissue. The different relationships between HIV persistence and T-cell subsets and chemokines in rectal and LN tissue suggest that different tissue-specific strategies may be required to eliminate HIV persistence and that assessment of biomarkers for HIV persistence may not be generalizable between blood and other tissues.

Serial MRI Findings After Endoscopic Removal of Button Battery From the Esophagus.

OBJECTIVE. The purpose of this study was to evaluate findings at serial MRI after endoscopic removal of a button battery from the esophagus in a series of pediatric patients. MATERIALS AND METHODS. Serial MRI examinations after removal of a button battery from the esophagus were reviewed retrospectively for the presence of mediastinal edema; imaging characteristics of the aorta and arteries; imaging characteristics of the trachea; and imaging characteristics of the esophageal wall at the level of injury. RESULTS. A total of 48 MRI examinations were performed on 19 patients, 89% (17/19) in the first 48 hours after battery removal. Serial MRI was performed for 84% (16/19) of patients. Initial MRI showed extensive mediastinal edema in all 17 patients who underwent MRI in the first 48 hours. Edema directly abutted major arteries in all 17 patients and abutted the airway in all 10 patients with proximal esophageal injury. Arterial vascular changes were seen in 30% (3/10) of patients with proximal esophageal injury and 57% (4/7) of patients with mid or distalesophageal injury. Airway changes were seen in 80% (8/10) of patients with proximal esophageal injury. Serial MRI showed improvement of airway changes in all patients and improvement in vessel wall changes in all but one (25%, 1/4) of the patients who had mid or distal esophageal injury. Four patients (21% [4/19]) had contained esophageal leak on esophagrams. No patients in our series developed a tracheoesophageal or vascular-enteric fistula. CONCLUSION. Our case series provides important information on natural history of MRI findings in children after endoscopic removal of a button battery from the esophagus. Further studies are needed to determine the imaging findings most sensitive and specific for severe complications, such as tracheoesophageal fistula and vascular-enteric fistula.

Correction: Effects of Combined CCR5/Integrase Inhibitors-Based Regimen on Mucosal Immunity in HIV-Infected Patients Naïve to Antiretroviral Therapy: A Pilot Randomized Trial.

[This corrects the article DOI: 10.1371/journal.ppat.1005381.].

Wide outcrossing provides functional connectivity for new and old Banksia populations within a fragmented landscape.

Habitat fragmentation affects landscape connectivity, the extent of which is influenced by the movement capacity of the vectors of seed and pollen dispersal for plants. Negative impacts of reduced connectivity can include reduced fecundity, increased inbreeding, genetic erosion and decreased long-term viability. These are issues for not only old (remnant) populations, but also new (restored) populations. We assessed reproductive and connective functionality within and among remnant and restored populations of a common tree, Banksia menziesii R.Br. (Proteaceae), in a fragmented urban landscape, utilising a genetic and graph theoretical approach. Adult trees and seed cohorts from five remnants and two restored populations were genotyped using microsatellite markers. Genetic variation and pollen dispersal were assessed using direct (paternity assignment) and indirect (pollination graphs and mating system characterisation) methods. Restored populations had greater allelic diversity (Ar = 8.08; 8.34) than remnant populations (Ar range = 6.49-7.41). Genetic differentiation was greater between restored and adjacent remnants (FST = 0.03 and 0.10) than all other pairwise comparisons of remnant populations (mean FST = 0.01 ± 0.01; n = 16 P = 0.001). All populations displayed low correlated paternity (rp = 0.06-0.16) with wide-ranging realised pollen dispersal distances (< 1.7 km) and well-connected pollen networks. Here, we demonstrate reproductive and connective functionality of old and new populations of B. menziesii within a fragmented landscape. Due to long-distance pollination events, the physical size of these sites underestimates their effective population size. Thus, they are functionally equivalent to large populations, integrated into a larger landscape matrix.

CD4+ T Cells Expressing PD-1, TIGIT and LAG-3 Contribute to HIV Persistence during ART.

HIV persists in a small pool of latently infected cells despite antiretroviral therapy (ART). Identifying cellular markers expressed at the surface of these cells may lead to novel therapeutic strategies to reduce the size of the HIV reservoir. We hypothesized that CD4+ T cells expressing immune checkpoint molecules would be enriched in HIV-infected cells in individuals receiving suppressive ART. Expression levels of 7 immune checkpoint molecules (PD-1, CTLA-4, LAG-3, TIGIT, TIM-3, CD160 and 2B4) as well as 4 markers of HIV persistence (integrated and total HIV DNA, 2-LTR circles and cell-associated unspliced HIV RNA) were measured in PBMCs from 48 virally suppressed individuals. Using negative binomial regression models, we identified PD-1, TIGIT and LAG-3 as immune checkpoint molecules positively associated with the frequency of CD4+ T cells harboring integrated HIV DNA. The frequency of CD4+ T cells co-expressing PD-1, TIGIT and LAG-3 independently predicted the frequency of cells harboring integrated HIV DNA. Quantification of HIV genomes in highly purified cell subsets from blood further revealed that expressions of PD-1, TIGIT and LAG-3 were associated with HIV-infected cells in distinct memory CD4+ T cell subsets. CD4+ T cells co-expressing the three markers were highly enriched for integrated viral genomes (median of 8.2 fold compared to total CD4+ T cells). Importantly, most cells carrying inducible HIV genomes expressed at least one of these markers (median contribution of cells expressing LAG-3, PD-1 or TIGIT to the inducible reservoir = 76%). Our data provide evidence that CD4+ T cells expressing PD-1, TIGIT and LAG-3 alone or in combination are enriched for persistent HIV during ART and suggest that immune checkpoint blockers directed against these receptors may represent valuable tools to target latently infected cells in virally suppressed individuals.

Effects of Combined CCR5/Integrase Inhibitors-Based Regimen on Mucosal Immunity in HIV-Infected Patients Naïve to Antiretroviral Therapy: A Pilot Randomized Trial.

Whether initiation of antiretroviral therapy (ART) regimens aimed at achieving greater concentrations within gut associated lymphoid tissue (GALT) impacts the level of mucosal immune reconstitution, inflammatory markers and the viral reservoir remains unknown. We included 12 HIV- controls and 32 ART-naïve HIV patients who were randomized to efavirenz, maraviroc or maraviroc+raltegravir, each with fixed-dose tenofovir disoproxil fumarate/emtricitabine. Rectal and duodenal biopsies were obtained at baseline and at 9 months of ART. We performed a comprehensive assay of T-cell subsets by flow cytometry, T-cell density in intestinal biopsies, plasma and tissue concentrations of antiretroviral drugs by high-performance liquid chromatography/mass spectroscopy, and plasma interleukin-6 (IL-6), lipoteichoic acid (LTA), soluble CD14 (sCD14) and zonulin-1 each measured by ELISA. Total cell-associated HIV DNA was measured in PBMC and rectal and duodenal mononuclear cells. Twenty-six HIV-infected patients completed the follow-up. In the duodenum, the quadruple regimen resulted in greater CD8+ T-cell density decline, greater normalization of mucosal CCR5+CD4+ T-cells and increase of the naïve/memory CD8+ T-cell ratio, and a greater decline of sCD14 levels and duodenal HIV DNA levels (P = 0.004 and P = 0.067, respectively), with no changes in HIV RNA in plasma or tissue. Maraviroc showed the highest drug distribution to the gut tissue, and duodenal concentrations correlated well with other T-cell markers in duodenum, i.e., the CD4/CD8 ratio, %CD4+ and %CD8+ HLA-DR+CD38+ T-cells. Maraviroc use elicited greater activation of the mucosal naïve CD8+ T-cell subset, ameliorated the distribution of the CD8+ T-cell maturational subsets and induced higher improvement of zonulin-1 levels. These data suggest that combined CCR5 and integrase inhibitor based combination therapy in ART treatment naïve patients might more effectively reconstitute duodenal immunity, decrease inflammatory markers and impact on HIV persistence by cell-dependent mechanisms, and show unique effects of MVC in duodenal immunity driven by higher drug tissue penetration and possibly by class-dependent effects.

Seeds in motion: Genetic assignment and hydrodynamic models demonstrate concordant patterns of seagrass dispersal.

Movement is fundamental to the ecology and evolutionary dynamics within species. Understanding movement through seed dispersal in the marine environment can be difficult due to the high spatial and temporal variability of ocean currents. We employed a mutually enriching approach of population genetic assignment procedures and dispersal predictions from a hydrodynamic model to overcome this difficulty and quantify the movement of dispersing floating fruit of the temperate seagrass Posidonia australis Hook.f. across coastal waters in south-western Australia. Dispersing fruit cohorts were collected from the water surface over two consecutive years, and seeds were genotyped using microsatellite DNA markers. Likelihood-based genetic assignment tests were used to infer the meadow of origin for seed cohorts and individuals. A three-dimensional hydrodynamic model was coupled with a particle transport model to simulate the movement of fruit at the water surface. Floating fruit cohorts were mainly assigned genetically to the nearest meadow, but significant genetic differentiation between cohort and most likely meadow of origin suggested a mixed origin. This was confirmed by genetic assignment of individual seeds from the same cohort to multiple meadows. The hydrodynamic model predicted 60% of fruit dispersed within 20 km, but that fruit was physically capable of dispersing beyond the study region. Concordance between these two independent measures of dispersal provides insight into the role of physical transport for long distance dispersal of fruit and the consequences for spatial genetic structuring of seagrass meadows.

Epigenetic mechanisms, T-cell activation, and CCR5 genetics interact to regulate T-cell expression of CCR5, the major HIV-1 coreceptor.

T-cell expression levels of CC chemokine receptor 5 (CCR5) are a critical determinant of HIV/AIDS susceptibility, and manifest wide variations (i) between T-cell subsets and among individuals and (ii) in T-cell activation-induced increases in expression levels. We demonstrate that a unifying mechanism for this variation is differences in constitutive and T-cell activation-induced DNA methylation status of CCR5 cis-regulatory regions (cis-regions). Commencing at an evolutionarily conserved CpG (CpG -41), CCR5 cis-regions manifest lower vs. higher methylation in T cells with higher vs. lower CCR5 levels (memory vs. naïve T cells) and in memory T cells with higher vs. lower CCR5 levels. HIV-related and in vitro induced T-cell activation is associated with demethylation of these cis-regions. CCR5 haplotypes associated with increased vs. decreased gene/surface expression levels and HIV/AIDS susceptibility magnify vs. dampen T-cell activation-associated demethylation. Methylation status of CCR5 intron 2 explains a larger proportion of the variation in CCR5 levels than genotype or T-cell activation. The ancestral, protective CCR5-HHA haplotype bears a polymorphism at CpG -41 that is (i) specific to southern Africa, (ii) abrogates binding of the transcription factor CREB1 to this cis-region, and (iii) exhibits a trend for overrepresentation in persons with reduced susceptibility to HIV and disease progression. Genotypes lacking the CCR5-Δ32 mutation but with hypermethylated cis-regions have CCR5 levels similar to genotypes heterozygous for CCR5-Δ32. In HIV-infected individuals, CCR5 cis-regions remain demethylated, despite restoration of CD4+ counts (≥800 cells per mm(3)) with antiretroviral therapy. Thus, methylation content of CCR5 cis-regions is a central epigenetic determinant of T-cell CCR5 levels, and possibly HIV-related outcomes.

Human Immunodeficiency Virus Persistence and T-Cell Activation in Blood, Rectal, and Lymph Node Tissue in Human Immunodeficiency Virus-Infected Individuals Receiving Suppressive Antiretroviral Therapy.

Background: Immune activation and inflammation remain elevated in human immunodeficiency virus (HIV)-infected individuals receiving antiretroviral therapy (ART) and may contribute to HIV persistence. Methods: Using flow cytometry expression of CD38, HLA-DR and PD-1 were measured in blood (n = 48), lymph node (LN; n = 9), and rectal tissue (n = 17) from virally suppressed individuals. Total and integrated HIV DNA, 2-LTR circles, and cell-associated unspliced HIV RNA were quantified. Results: CD4+ T cells from rectal tissue had a higher frequency of integrated HIV DNA compared with blood (4.26 fold-change in DNA; 95% confidence interval [CI] = 2.61-7.00; P < .001) and LN (2.32 fold-change in DNA; 95% CI = 1.22-4.41; P = .01). In rectal tissue, there were positive associations between integrated HIV DNA with PD-1+ CD4+ T-cells (1.44 fold-change in integrated HIV DNA per 10-unit increase in PD-1+ CD4+ T cells; 95% CI = 1.01-2.05; P = .045) and CD38+HLA-DR+ CD8+ T cells (1.40 fold-change in integrated HIV DNA per 1-unit increase in CD38+HLA-DR+ CD8+ T cells; 95% CI = 1.05-1.86; P = .02). Both associations were independent of current and nadir CD4+ T-cell counts. Conclusions: During ART, rectal tissue is an important reservoir for HIV persistence with a high frequency of activated CD4+ and CD8+ T cells. PD-1 may represent a marker of HIV persistence in rectal tissue.

Chronic stress is associated with reduced circulating hematopoietic progenitor cell number: A maternal caregiving model.

BACKGROUND: Chronic psychological stress is a risk factor for cardiovascular disease and mortality. Circulating hematopoietic progenitor cells (CPCs) maintain vascular homeostasis, correlate with preclinical atherosclerosis, and prospectively predict cardiovascular events. We hypothesize that (1) chronic caregiving stress is related to reduced CPC number, and (2) this may be explained in part by negative interactions within the family. METHODS: We investigated levels of stress and CPCs in 68 healthy mothers - 31 of these had children with an autism spectrum disorder (M-ASD) and 37 had neurotypical children (M-NT). Participants provided fasting blood samples, and CD45+CD34+KDR+ and CD45+CD133+KDR+ CPCs were assayed by flow cytometry. We averaged the blom-transformed scores of both CPCs to create one index. Participants completed the perceived stress scale (PSS), the inventory for depressive symptoms (IDS), and reported on daily interactions with their children and partners, averaged over 7 nights. RESULTS: M-ASD exhibited lower CPCs than M-NT (Cohen's d=0.83; p⩽0.01), controlling for age, BMI, and physical activity. Across the whole sample, positive interactions were related to higher CPCs, and negative interactions to lower CPCs (allp's<0.05). The adverse effects of group on CPCs were significantly mediated through negative interactions with the child (indirect ß=-0.24, p⩽0.01). In the full model, greater age (ß=-0.19, p=0.04), BMI (ß=-0.18, p=0.04), and negative interactions with the child (ß=-0.33, p<0.01) were independently associated with lower CPCs. M-ASD had a less healthy lipid profile (total cholesterol/HDL), which in turn, was associated with lower CPCs. CONCLUSIONS: Chronic stress adversely impacts CPC number, an early-stage biomarker that predicts subclinical atherosclerosis and future CVD events, independent of traditional cardiovascular risk factors and inflammatory factors. Among maternal caregivers, child-related interpersonal stress appears to be a key psychological predictor of stress-related CVD risk.