Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation.

Changes in the Atlantic Meridional Overturning Circulation, which have the potential to drive societally-important climate impacts, have traditionally been linked to the strength of deep water formation in the subpolar North Atlantic. Yet there is neither clear observational evidence nor agreement among models about how changes in deep water formation influence overturning. Here, we use data from a trans-basin mooring array (OSNAP-Overturning in the Subpolar North Atlantic Program) to show that winter convection during 2014-2018 in the interior basin had minimal impact on density changes in the deep western boundary currents in the subpolar basins. Contrary to previous modeling studies, we find no discernable relationship between western boundary changes and subpolar overturning variability over the observational time scales. Our results require a reconsideration of the notion of deep western boundary changes representing overturning characteristics, with implications for constraining the source of overturning variability within and downstream of the subpolar region.

Non-Bee Insects as Visitors and Pollinators of Crops: Biology, Ecology, and Management.

Insects other than bees (i.e., non-bees) have been acknowledged as important crop pollinators, but our understanding of which crop plants they visit and how effective they are as crop pollinators is limited. To compare visitation and efficiency of crop-pollinating bees and non-bees at a global scale, we review the literature published from 1950 to 2018 concerning the visitors and pollinators of 105 global food crops that are known to benefit from animal pollinators. Of the 105 animal-pollinated crops, a significant proportion are visited by both bee and non-bee taxa (n = 82; 77%), with a total gross domestic product (GDP) value of US$780.8 billion. For crops with a narrower range of visitors, those that favor non-bees (n = 8) have a value of US$1.2 billion, compared to those that favor bees (n = 15), with a value of US$19.0 billion. Limited pollinator efficiency data were available for one or more taxa in only half of the crops (n = 61; 58%). Among the non-bees, some families were recorded visiting a wide range of crops (>12), including six families of flies (Syrphidae, Calliphoridae, Muscidae, Sarcophagidae, Tachinidae, and Bombyliidae), two beetle families (Coccinelidae and Nitidulidae), ants (Formicidae), wasps (Vespidae), and four families of moths and butterflies (Hesperiidae, Lycaenidae, Nymphalidae, and Pieridae). Among the non-bees, taxa within the dipteran families Syrphidae and Calliphoridae were the most common visitors to the most crops, but this may be an artifact of the limited data available. The diversity of species and life histories in these groups of lesser-known pollinators indicates that diet, larval requirements, and other reproductive needs will require alternative habitat management practices to bees.

Pollination and resource limitation as interacting constraints on almond fruit set.

Pollination and resource availability are factors determining reproductive success of plants, and in agriculture these factors influence yield of fruit-bearing crops. Our understanding of the importance of crop pollination is fast improving, but less is known about how the interaction between pollination and resources constrains fruit production. We conducted an experiment with almond trees (Prunus dulcis) to examine how the number of flowers, light availability and competition for resources affected nut (fruit) production on individual spurs (fruit-bearing structures) exposed to open-pollination or hand-pollination. We found a positive relationship between flower number and nut number on spurs with up to four flowers, but no further benefit after four flowers, suggesting a resource threshold expressed by individual spurs. Spurs with few flowers increased the conversion rate of flowers to nuts when supplemented with hand-pollination, but spurs with more flowers were more likely to achieve the threshold number of nuts even under open-pollination. Our experiment included a further treatment involving spraying whole trees with pollen. This treatment reduced nut production by spurs with many flowers and high light availability, suggesting competition is experienced by well-resourced spurs when resources need to be shared among developing nuts across the whole tree. Our study supports the hypothesis that excess flower production in fruit trees increases the potential for fruit production when pollinator and resource availability is variable (bet-hedging). Spurs with more flowers typically produce more nuts (within a limited range), but only if both resources and pollen supply increase with flower number. For almond growers, a focus on maintaining high flower numbers, especially in high light regions of the canopy, is the foundation for high levels of production. Strategies to lift flower number and light are complicated by trade-offs inherent in tree architecture and orchard design. However, fruit set would be lifted above that achieved by current practice by an increase in the pollination rate of flowers.

A sea change in our view of overturning in the subpolar North Atlantic.

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

Subpolar North Atlantic Overturning and Gyre-Scale Circulation in the Summers of 2014 and 2016.

The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the global climate system through its transport of heat and freshwater. The subpolar North Atlantic (SPNA) is a region where the AMOC is actively developed and shaped though mixing and water mass transformation and where large amounts of heat are released to the atmosphere. Two hydrographic transbasin sections in the summers of 2014 and 2016 provide highly spatially resolved views of the SPNA velocity and property fields on a line from Canada to Greenland to Scotland. Estimates of the AMOC, isopycnal (gyre-scale) transport, and heat and freshwater transport are derived from the observations. The overturning circulation, the maximum in northward transport integrated from the surface to seafloor and computed in density space, has a high range, with 20.6 ± 4.7 Sv in June-July 2014 and 10.6 ± 4.3 Sv in May-August 2016. In contrast, the isopycnal (gyre-scale) circulation was lowest in summer 2014: 41.3 ± 8.2 Sv compared to 58.6 ± 7.4 Sv in 2016. The heat transport (0.39 ± 0.08 PW in summer 2014, positive is northward) was highest for the section with the highest AMOC, and the freshwater transport was largest in summer 2016 when the isopycnal circulation was high (-0.25 ± 0.08 Sv). Up to 65% of the heat and freshwater transport was carried by the isopycnal circulation, with isopycnal property transport highest in the western Labrador Sea and the eastern basins (Iceland Basin to Scotland).

Evaluation of a real-time PCR assay for rectal screening of OXA-48-producing Enterobacteriaceae in a general intensive care unit of an endemic hospital.

Carbapenemase-producing Enterobacteriaceae are increasing worldwide. Rectal screening for these bacteria can inform the management of infected and colonized patients, especially those admitted to intensive care units (ICUs). A laboratory developed, qualitative duplex real-time polymerase chain reaction assay for rapid detection of OXA-48-like and VIM producing Enterobacteriaceae, performed on rectal swabs, was designed and evaluated in an intensive care unit with endemic presence of OXA-48. During analytical assay validation, no cross-reactivity was observed and 100% sensitivity and specificity were obtained for both blaOXA-48-like and blaVIM in all spiked clinical samples. During the clinical part of the study, the global sensitivity and specificity of the real-time PCR assay for OXA-48 detection were 95.7% and 100% (P=0.1250), respectively, in comparison with culture; no VIM-producing Enterobacteriaceae were detected. Clinical features of patients in the ICU who were colonized or infected with OXA-48 producing Enterobacteriaceae, including outcome, were analyzed. Most had severe underlying conditions, and had risk factors for colonization with carbapenemase-producing Enterobacteriaceae before or during ICU admission, such as receiving previous antimicrobial therapy, prior healthcare exposure (including long-term care), chronic disease, immunosuppression and/or the presence of an intravascular catheter and/or mechanical ventilation device. The described real-time PCR assay is fast (~2-3hours, if DNA extraction is included), simple to perform and results are easy to interpret, features which make it applicable in the routine of clinical microbiology laboratories. Implementation in endemic hospitals could contribute to early detection of patients colonized by OXA-48 producing Enterobacteriaceae and prevention of their spread.

Relationship between prenatal growth, postnatal growth and childhood obesity: a review.

Evidence is accumulating that obesity risks become established early in life. The goal of this systematic review is to assess whether there is evidence that rapid postnatal growth holds different implications for childhood obesity risks for children who experienced different patterns of prenatal growth. We conducted systematic database searches in PubMed and Embase in October 2014 for studies assessing the implications of prenatal and postnatal growth for childhood obesity. The 18 studies meeting inclusion criteria indicated that risks of obesity increased with birthweight; risks of obesity also increased with rapid postnatal growth for children across the birthweight distribution. Fifteen studies indicated that rapid postnatal growth is linearly associated with obesity for children and adolescents of all sizes at birth, with no interaction effect. Three studies reported interaction effects with postnatal growth, conferring additional increased risk of obesity among children and adolescents who were small at birth. Both prenatal and postnatal growth are important risk factors for obesity, and their combined effects should be analyzed further to understand how obesity risks develop early in life.

Before-school and after-school childcare and children's risk of obesity.

BACKGROUND: In the USA, half of children are regularly cared for before or after school by someone other than a parent. OBJECTIVE: Describe the relationship between childcare arrangements and obesity among school-aged children. METHODS: Data are from the fifth-grade wave of the Early Childhood Longitudinal Study - Kindergarten Cohort 1998-1999, a nationally representative study of US children who were in kindergarten in 1998-1999 or first grade in 1999, collected in spring 2004 (analytic sample = 9617). We estimated survey-adjusted logistic regression models to examine the association between childcare arrangements before and after school and obesity. RESULTS: The prevalence of obesity was highest among fifth graders who received care from multiple sources and lowest among children who received care from adults not related to them in either the child's or the caregiver's home [29.9%, 95% confidence interval {CI}: 18.7%, 44.3%; and 17.3%, 95% CI: 12.1%, 24.0%]. Childcare arrangement was not an independent risk factor for obesity for most children. However, Hispanic children who were cared for by a person who was not a relative had significantly higher odds of obesity compared with non-Hispanics in similar care arrangements (odds ratio: 5.11, 95% CI: 2.00, 13.06). CONCLUSION: Type of childcare before or after school was not an independent risk factor for obesity in most fifth graders, but implications of childcare for Hispanic children should be explored further.

Ureaplasma parvum causes hyperammonemia in a pharmacologically immunocompromised murine model.

A relationship between hyperammonemia and Ureaplasma infection has been shown in lung transplant recipients. We have demonstrated that Ureaplasma urealyticum causes hyperammonemia in a novel immunocompromised murine model. Herein, we determined whether Ureaplasma parvum can do the same. Male C3H mice were given mycophenolate mofetil, tacrolimus, and prednisone for 7 days, and then challenged with U. parvum intratracheally (IT) and/or intraperitoneally (IP), while continuing immunosuppression over 6 days. Plasma ammonia concentrations were determined and compared using Wilcoxon rank-sum tests. Plasma ammonia concentrations of immunosuppressed mice challenged IT/IP with spent broth (median, 188 µmol/L; range, 102-340 µmol/L) were similar to those of normal (median, 226 µmol/L; range, 154-284 µmol/L, p > 0.05), uninfected immunosuppressed (median, 231 µmol/L; range, 122-340 µmol/L, p > 0.05), and U. parvum IT/IP challenged immunocompetent (median, 226 µmol/L; range, 130-330 µmol/L, p > 0.05) mice. Immunosuppressed mice challenged with U. parvum IT/IP (median 343 µmol/L; range 136-1,000 µmol/L) or IP (median 307 µmol/L; range 132-692 µmol/L) had higher plasma ammonia concentrations than those challenged IT/IP with spent broth (p < 0.001). U. parvum can cause hyperammonemia in pharmacologically immunocompromised mice.

Does morphology predict trophic position and habitat use of ant species and assemblages?

A functional traits-based theory of organismal communities is critical for understanding the principles underlying community assembly, and predicting responses to environmental change. This is particularly true for terrestrial arthropods, of which only 20% are described. Using epigaeic ant assemblages, we asked: (1) can we use morphological variation among species to predict trophic position or preferred microhabitat; (2) does the strength of morphological associations suggest recent trait divergence; (3) do environmental variables at site scale predict trait sets for whole assemblages? We pitfall-trapped ants from a revegetation chronosequence and measured their morphology, trophic position [using C:N stoichiometry and stable isotope ratios (δ)] and characteristics of microhabitat and macrohabitat. We found strong associations between high trophic position (low C:N and high δ(15)N) in body tissue and morphological traits: predators were larger, had more laterally positioned eyes, more physical protection and tended to be monomorphic. In addition, morphological traits were associated with certain microhabitat features, e.g. smaller heads were associated with the bare ground microhabitat. Trait-microhabitat relationships were more pronounced when phylogenetic adjustments were used, indicating a strong influence of recent trait divergences. At the assemblage level, our fourth corner analysis revealed associations between the prevalence of traits and macrohabitat, although these associations were not the same as those based on microhabitat associations. This study shows direct links between species-level traits and both diet and habitat preference. Trait-based prediction of ecological roles and community structure is thus achievable when integrating stoichiometry, morphology and phylogeny, but scale is an important consideration in such predictions.

Inhibition controls for qualitative real-time PCR assays: are they necessary for all specimen matrices?

A retrospective analysis of 386,706 specimens representing a variety of matrix types used in qualitative real-time PCR assays determined the overall inhibition rate to be 0.87% when the inhibition control was added preextraction to 5,613 specimens and 0.01% when the inhibition control was added postextraction but preamplification in 381,093 specimens. Inhibition rates of ≤ 1% were found for all specimen matrix types except urine and formalin-fixed, paraffin-embedded tissue.

The weight of US residence among immigrants: a systematic review.

As the number of immigrants in the USA continues to rise, it becomes increasingly important to understand how their health differs from native-born individuals. Obesity is a public health concern and a component of health that may differ and change in important ways in immigrants. This research synthesizes the current literature on the relationship between immigrant duration of residence in the USA and body weight. Five databases from the health and social sciences were searched for all pertinent publications. Fifteen articles met inclusion criteria, 14 of which reported a significant, positive relationship between body mass index and duration of residence in the USA (all P-values <0.10). Two studies reported a threshold effect of weight gain after 10 years of US residence, and another study reported that body mass index peaks after 21 years of duration for men and after 15 years for women. The results of this review suggest that weight gain prevention programmes would be beneficial for many immigrants within the first decade of residence in the USA. Prevention efforts may be more successful if nativity and acculturation are considered in addition to race/ethnicity. Future research is needed to identify the specific mechanisms through which living in the USA may adversely affect health outcomes.

Herbivory differentially affects male and female reproductive traits of Cucumis sativus.

Herbivory is an important selection pressure in the life history of plants. Most studies use seed or fruit production as an indication of plant fitness, but the impact of herbivory on male reproductive success is usually ignored. It is possible that plants compensate for resources lost to herbivory by shifting the allocation from seed production to pollen production and export, or vice versa. This study examined the impact of herbivory by Helix aspersa on both male and female reproductive traits of a monoecious plant, Cucumis sativus. The effects of herbivory on the relative allocation to male and female flowers were assessed through measurements of the number and size of flowers of both sexes, and the amount of pollinator visitation. We performed two glasshouse experiments; the first looked at the impact of three levels of pre-flowering herbivory, and the second looked at four levels of herbivory after the plants had started to flower. We found that herbivory during the flowering phase led to a significant increase in the number of plants without male flowers. As a consequence there was significantly less pollen export from this population, as estimated by movement of a pollen analog. The size of female flowers was reduced by severe herbivory, but there was no affect on pollen receipt by the female flowers of damaged plants. The decrease in allocation to male function after severe herbivory may be adaptive when male reproductive success is very unpredictable.

Cloning of human junctional adhesion molecule 3 (JAM3) and its identification as the JAM2 counter-receptor.

We have identified a third member of the junctional adhesion molecule (JAM) family. At the protein level JAM3 displays 36 and 32% identity to JAM2 and JAM1, respectively. The coding region is distributed over 9 exons and maps to chromosome 11q25. The gene shows widespread tissue expression with higher levels apparent in the kidney, brain, and placenta. At the cellular level we show expression of JAM3 transcript within endothelial cells. Our major finding is that JAM3 and JAM2 are binding partners. Thus, JAM3 ectodomain binds firmly to JAM2-Fc. This heterotypic interaction is maintained when JAM3-Fc is used to capture Chinese hamster ovary cells expressing full-length JAM2. In static adhesion assays we show that JAM3 is unable to bind to leukocyte cell lines. This is consistent with the lack of JAM2 expression. However, using JAM2-Fc pull-down experiments in combination with polyclonal anti-JAM3 serum, we demonstrate that JAM3 is the previously uncharacterized 43-kDa counter-receptor that mediates JAM2 adhesion to T cells. Most significantly we demonstrate up-regulation of JAM3 protein on peripheral blood lymphocytes following activation. Finally we show the utility of JAM3 ectodomain as an inhibitor of JAM2 adhesion.

Motor nerve topology reflects myocyte morphology in hamster retractor and epitrochlearis muscles.

Neuromuscular activation is a primary determinant of metabolic demand and oxygen transport. The m. retractor and m. epitrochlearis are model systems for studying metabolic control and oxygen transport; however, the organization of muscle fibers and motor nerves in these muscles is unknown. We tested whether the topology of motor innervation was related to the morphology of muscle fibers in m. retractor and m. epitrochlearis of male hamsters ( approximately 100 g). Respective muscles averaged 47 and 12 mm in length 100 and 35 mg in mass. Staining for acetylcholinesterase revealed neuromuscular junctions arranged in clusters throughout m. retractor and as a central band across m. epitrochlearis, suggesting differences in fiber morphology. For both muscles, complete cross-sections contained approximately 1,700 fibers. Fiber cross-sectional areas were distributed nearly normal in m. epitrochlearis (mean = 1,559 +/- 17 microm(2)) and skewed left (P < 0.05) in m. retractor (mean = 973 +/- 15 microm(2)). Single fiber length (Lf) spanned muscle length (Lm) in m. epitrochlearis, while fibers tapered to terminate within m. retractor (Lf/Lm = 0.43 +/- 0. 02). With myelin staining, a single branch of ulnar nerve projected axons across the midregion of m. epitrochlearis. For m. retractor, the spinal accessory nerve branched to give rise to proximal and distal regions of innervation, with intermingling of axons between nerve branches. Nerve bundle cross-sections stained for acetylcholinesterase indicate that each motor axon projects to an average of 65 muscle fibers in m. epitrochlearis and 100 in m. retractor. Differences in fiber morphology, innervation topology, and neuromuscular organization may contribute to the heterogeneity of metabolic demand and oxygen supply in skeletal muscle.

A novel protein with homology to the junctional adhesion molecule. Characterization of leukocyte interactions.

We have cloned a novel cDNA belonging to the Ig superfamily that shows 44% similarity to the junctional adhesion molecule (JAM) and maps to chromosome 21q21.2. The open reading frame of JAM2 predicts a 34-kDa type I integral membrane protein that features two Ig-like folds and three N-linked glycosylation sites in the extracellular domain. A single protein kinase C phosphorylation consensus site and a PDZ-binding motif are present in the short intracellular tail. Heterologous expression of JAM2 in Chinese hamster ovary cells defined a 48-kDa protein that localizes predominantly to the intercellular borders. Northern blot analysis showed that JAM2 is preferentially expressed in the heart. JAM2 homotypic interactions were demonstrated by the ability of JAM2-Fc to capture JAM2-expressing Chinese hamster ovary cells. We further showed that JAM2, but not JAM1, is capable of adhering to the HSB and HPB-ALL lymphocyte cell lines. Neutralizing mouse anti-JAM2 polyclonal antibodies provided evidence against homotypic interactions in this assay. Biotinylation of HSB cell membranes revealed a 43-kDa counter-receptor that precipitates specifically with JAM2-Fc. These characteristics of JAM2 led us to hypothesize a role for this novel protein in adhesion events associated with cardiac inflammatory conditions.

Depressed pollination in habitat fragments causes low fruit set.

In central New South Wales, Australia, flowers of Acacia brachybotrya and Eremophila glabra plants growing in linear vegetation remnants received less pollen than conspecifics in nearby reserves. Pollen supplementation increased fruit production by both species, indicating pollen limitation of fruit set. Together these observations explain why fruit production by these species was depressed in linear-strip populations relative to nearby reserves. This study confirms that habitat fragmentation can lead to decline in pollination and subsequent fruit set in wild plant populations. Disrupted pollination interactions of the kind documented in this study may offer a substantial challenge to the conservation of biodiversity in fragmented landscapes.

Characterization of vascular endothelial cell growth factor interactions with the kinase insert domain-containing receptor tyrosine kinase. A real time kinetic study.

The kinase insert domain-containing receptor (KDR) tyrosine kinase mediates calcium mobilization in endothelial cells and plays a key role during physiological and pathological angiogenesis. To provide a detailed understanding of how KDR is activated, we analyzed the kinetics of ligand-receptor interaction using BIAcore. Both predimerized (KDR-Fc) and monomeric (KDR-cbu) receptors were examined with vascular endothelial cell growth factor (VEGF) homodimers and VEGF/placental growth factor (PlGF) heterodimers. VEGF binds to KDR-Fc with ka = 3.6 +/- 0.07e6, kd = 1.34 +/- 0.19e-4, and KD = 37.1 +/- 4.9 pM. These values are similar to those displayed by monomeric KDR where ka = 5.23 +/- 1.4e6, kd = 2.74 +/- 0.76e-4, and KD = 51.7 +/- 5.8 pM were apparent. In contrast, VEGF/PlGF bound to KDR-Fc with ka = 7.3 +/- 1.6e4, kd = 4.4 +/- 1. 2e-4, and KD = 6 +/- 1.2 nM. Thus, the heterodimer displays a 160-fold reduced KD for binding to predimerized KDR, which is mainly a consequence of a 50-fold reduction in ka. We were unable to detect association between VEGF/PlGF and monomeric KDR. However, nanomolar concentrations of VEGF/PlGF were able to elicit weak calcium mobilization in endothelial cells. This latter observation may indicate partial predimerization of KDR on the cell surface or facilitation of binding due to accessory receptors.

KDR activation is crucial for VEGF165-mediated Ca2+ mobilization in human umbilical vein endothelial cells.

We have prepared a polyclonal mouse antibody directed against the first three immunoglobulin-like domains of the kinase insert domain-containing receptor (KDR) tyrosine kinase. It possesses the ability to inhibit binding of the 165-amino acid splice variant of vascular endothelial cell growth factor (VEGF165) to recombinant KDR in vitro as well as to reduce VEGF165 binding to human umbilical vein endothelial cells (HUVEC). These results confirm that the first three immunoglobulin-like domains of KDR are involved in VEGF165 interactions. The anti-KDR antibody is able to completely block VEGF165-mediated intracellular Ca2+ mobilization in HUVEC. Therefore, it appears that binding of VEGF165 to the fms-like tyrosine kinase (Flt-1) in these cells does not translate into a Ca2+ response. This is further exemplified by the lack of response to placental growth factor (PlGF), an Flt-1-specific ligand. Additionally, PlGF is unable to potentiate the effects of submaximal concentrations of VEGF165. Surprisingly, the VEGF-PlGF heterodimer was also very inefficient at eliciting a Ca2+ signaling event in HUVEC. We conclude that KDR activation is crucial for mobilization of intracellular Ca2+ in HUVEC in response to VEGF165.