Unexpected hydrogen isotope variation in oceanic pelagic seabirds

Hydrogen isotopes have significantly enhanced our understanding of the biogeography of migratory animals. The basis for this methodology lies in predictable, continental patterns of precipitation δD values that are often reflected in an organism’s tissues. δD variation is not expected for oceanic pelagic organisms whose dietary hydrogen (water and organic hydrogen in prey) is transferred up the food web from an isotopically homogeneous water source. We report a 142 ‰ range in the δD values of flight feathers from the Hawaiian petrel (Pterodroma sandwichensis), an oceanic pelagic North Pacific species, and inquire about the source of that variation. We show δD variation between and within four other oceanic pelagic species: Newell’s shearwater (Puffinus auricularis newellii), Black-footed albatross (Phoebastria nigripes), Laysan albatross (Phoebastria immutabilis) and Buller’s shearwater (Puffinus bulleri). The similarity between muscle δD values of hatch-year Hawaiian petrels and their prey suggests that trophic fractionation does not influence δD values of muscle. We hypothesize that isotopic discrimination is associated with water loss during salt excretion through salt glands. Salt load differs between seabirds that consume isosmotic squid and crustaceans and those that feed on hyposmotic teleost fish. In support of the salt gland hypothesis, we show an inverse relationship between δD and percent teleost fish in diet for three seabird species. Our results demonstrate the utility of δD in the study of oceanic consumers, while also contributing to a better understanding of δD systematics, the basis for one of the most commonly utilized isotope tools in avian ecology.     

A novel intervention combining supplementary food and infection control measures to improve birth outcomes in undernourished pregnant women in Sierra Leone: A randomized,controlled clinical effectiveness trial

BackgroundInnovations for undernourished pregnant women that improve newborn survival and anthropometry are needed to achieve the Sustainable Development Goals 1 and 3. This study tested the hypothesis that a combination of a nutritious supplementary food and several proven chemotherapeutic interventions to control common infections would increase newborn weight and length in undernourished pregnant women.Methods and findingsThis was a prospective, randomized, controlled clinical effectiveness trial of a ready-to-use supplementary food (RUSF) plus anti-infective therapies compared to standard therapy in undernourished pregnant women in rural Sierra Leone. Women with a mid-upper arm circumference (MUAC) ≤23.0 cm presenting for antenatal care at one of 43 government health clinics in Western Rural Area and Pujehun districts were eligible for participation. Standard of care included a blended corn/soy flour and intermittent preventive treatment for malaria in pregnancy (IPTp). The intervention replaced the blended flour with RUSF and added azithromycin and testing and treatment for vaginal dysbiosis. Since the study involved different foods and testing procedures for the intervention and control groups, no one except the authors conducting the data analyses were blinded. The primary outcome was birth length. Secondary outcomes included maternal weight gain, birth weight, and neonatal survival. Follow-up continued until 6 months postpartum. Modified intention to treat analyses was undertaken. Participants were enrolled and followed up from February 2017 until February 2020.Of the 1,489 women enrolled, 752 were allocated to the intervention and 737 to the standard of care. The median age of these women was 19.5 years, of which 42% were primigravid. Twenty-nine women receiving the intervention and 42 women receiving the standard of care were lost to follow-up before pregnancy outcomes were obtained. There were 687 singleton live births in the intervention group and 657 in the standard of care group. Newborns receiving the intervention were 0.3 cm longer (95% confidence interval (CI) 0.09 to 0.6; p = 0.007) and weighed 70 g more (95% CI 20 to 120; p = 0.005) than those receiving the standard of care. Those women receiving the intervention had greater weekly weight gain (mean difference 40 g; 95% CI 9.70 to 71.0, p = 0.010) than those receiving the standard of care. There were fewer neonatal deaths in the intervention (n = 13; 1.9%) than in the standard of care (n = 28; 4.3%) group (difference 2.4%; 95% CI 0.3 to 4.4), (HR 0.62 95% CI 0.41 to 0.94, p = 0.026). No differences in adverse events or symptoms between the groups was found, and no serious adverse events occurred. Key limitations of the study are lack of gestational age estimates and unblinded administration of the intervention.ConclusionsIn this study, we observed that the addition of RUSF, azithromycin, more frequent IPTp, and testing/treatment for vaginal dysbiosis in undernourished pregnant women resulted in modest improvements in anthropometric status of mother and child at birth, and a reduction in neonatal death. Implementation of this combined intervention in rural, equatorial Africa may well be an important, practical measure to reduce infant mortality in this context.Trial registrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT03079388","term_id":"NCT03079388"}}NCT03079388.

In a randomized trial, D. Taylor Hendrixson and colleagues investigate the effect of an intervention combining supplementary food and anti-infection medications on birth outcomes.     

Dexamethasone alters F-actin architecture and promotes cross-linked actin network formation in human trabecular meshwork tissue

Elevated intraocular pressure is an important risk factor for the development of glaucoma, a leading cause of irreversible blindness. This ocular hypertension is due to increased hydrodynamic resistance to the drainage of aqueous humor through specialized outflow tissues, including the trabecular meshwork (TM) and the endothelial lining of Schlemm's canal. We know that glucocorticoid therapy can cause increased outflow resistance and glaucoma in susceptible individuals, that the cytoskeleton helps regulate aqueous outflow resistance, and that glucocorticoid treatment alters the actin cytoskeleton of cultured TM cells. Our purpose was to characterize the actin cytoskeleton of cells in outflow pathway tissues in situ, to characterize changes in the cytoskeleton due to dexamethasone treatment in situ, and to compare these with changes observed in cell culture. Human ocular anterior segments were perfused with or without 10(-7) M dexamethasone, and F-actin architecture was investigated by confocal laser scanning microscopy. We found that outflow pathway cells contained stress fibers, peripheral actin staining, and occasional actin "tangles." Dexamethasone treatment caused elevated IOP in several eyes and increased overall actin staining, with more actin tangles and the formation of cross-linked actin networks (CLANs). The actin architecture in TM tissues was remarkably similar to that seen in cultured TM cells. Although CLANs have been reported previously in cultured cells, this is the first report of CLANs in tissue. These cytoskeletal changes may be associated with increased aqueous humor outflow resistance after ocular glucocorticoid treatment.     

Insulin and IGF receptors are developmentally regulated in the chick embryo eye lens

We have previously reported that insulin-like growth factor (IGF) receptors appear to predominate over insulin receptors in early stages of embryogenesis in the chick (days 2-3 whole embryo membranes). Overall, [125I]IGF I and II binding to specific receptors was maximal when the rate of brain growth is highest. In the present study we used the embryonic chick lens, a well-defined tissue composed of a single type of cell, to analyse whether changes of insulin and IGF I binding are correlated with changes in growth rate and differentiation state of the cells. We show that both insulin receptors and IGF receptors are present in the lens epithelial cells, and that each type is distinctly regulated throughout development. While there is a direct correlation between IGF-binding capability and growth rate of the cells, there is less relation to differentiation status and embryo age. Insulin receptors, by contrast, appear to be mostly related to the differentiated state of cells, decreasing sharply in fibers, irrespective of their developmental age.     

Identification of DNA sequence variation in Campylobacter jejuni strains associated with the Guillain-Barré syndrome by high-throughput AFLP analysis

Background  

Campylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry between human gangliosides and bacterial lipo-oligosaccharides (LOS). This study describes a new C. jejuni-specific high-throughput AFLP (htAFLP) approach for detection and identification of DNA polymorphism, in general, and of putative GBS/MFS-markers, in particular.     

Polymix breeding with paternity analysis in Populus: a test for differential reproductive success (DRS) among pollen donors

Polymix breeding with paternity analysis (PMX/WPA) has been proposed as an alternative to traditional full-sib breeding and testing schemes. To fully capture the benefits of PMX/WPA, differential reproductive success (DRS) of pollen parents used in the polymix must be modest. DRS was evaluated in an operational test of PMX/WPA for a hybrid poplar breeding program. A 16-parent pollen polymix (Populus nigra L.) was used to pollinate seven clones of Populus deltoides (Bartr. ex. Marshall) under greenhouse breeding conditions. Progeny were grown out briefly and randomly sampled (357) prior to out-planting in field trials. Twenty-eight simple sequence repeat (SSR) loci were evaluated and 15 were selected for genetic characterization in small populations of three Populus spp (P. nigra, P. deltoides, and P. balsamifera spp trichocarpa Torr. & Gray). Seven loci were ultimately selected for paternity analysis of progeny. The average exclusion probability of the seven loci in P. nigra was 0.604; combined, the theoretical exclusion probability was 0.9999. However, only 95% of sampled progeny were unambiguously assigned a single paternal parent. Missing data likely accounted for most of the ambiguity. DRS was statistically significant though not prohibitive for practical utility of PMX/WPA as a breeding system. Of the 112 potential crosses in this study, 92 were represented. Eight of the 16 pollen parents contributed 83% of the progeny. Good pollen vigor, as measured by germination percent, did not ensure paternal success, but poor vigor was associated with lack of paternal success. PMX/WPA appears to be logistically and economically attractive for hybrid poplar breeding and testing.