A high-resolution record of early Paleozoic climate

The spatial coverage and temporal resolution of the Early Paleozoic paleoclimate record are limited, primarily due to the paucity of well-preserved skeletal material commonly used for oxygen-isotope paleothermometry. Bulk-rock δ¹⁸O datasets can provide broader coverage and higher resolution, but are prone to burial alteration. We assess the diagenetic character of two thick Cambro–Ordovician carbonate platforms with minimal to moderate burial by pairing clumped and bulk isotope analyses of micritic carbonates. Despite resetting of the clumped-isotope thermometer at both sites, our samples indicate relatively little change to their bulk δ¹⁸O due to low fluid exchange. Consequently, both sequences preserve temporal trends in δ¹⁸O. Motivated by this result, we compile a global suite of bulk rock δ¹⁸O data, stacking overlapping regional records to minimize diagenetic influences on overall trends. We find good agreement of bulk rock δ¹⁸O with brachiopod and conodont δ¹⁸O trends through time. Given evidence that the δ¹⁸O value of seawater has not evolved substantially through the Phanerozoic, we interpret this record as primarily reflecting changes in tropical, nearshore seawater temperatures and only moderately modified by diagenesis. Focusing on the samples with the most enriched, and thus likely least-altered, δ¹⁸O values, we reconstruct Late Cambrian warming, Early Ordovician extreme warmth, and cooling around the Early–Middle Ordovician boundary. Our record is consistent with models linking the Great Ordovician Biodiversification Event to cooling of previously very warm tropical oceans. In addition, our high-temporal-resolution record suggests previously unresolved transient warming and climate instability potentially associated with Late Ordovician tectonic events

Pyrite-walled tube structures in a Mesoproterozoic sediment-hosted metal sulfide deposit

Unusual decimeter-scale structures occur in the sediment-hosted Black Butte Copper Mine Project deposit within lower Mesoproterozoic strata of the Belt Supergroup, Montana. These low domal and stratiform lenses are made up of millimeter-scale, hollow or mineral-filled tubes bounded by pyrite walls. X-ray micro−computed tomography (micro-CT) shows that the tube structures are similar to the porous fabric of modern diffuse hydrothermal vents, and they do not resemble textures associated with the mineralization of known microbial communities. We determined the sulfur isotopic composition of sulfide minerals with in situ secondary ion mass spectrometry (SIMS) and of texture-specific sulfate phases with multicollector−inductively coupled plasma−mass spectrometry (MC-ICP-MS). The sedimentological setting, ore paragenesis, sulfur isotope systematics, and porosity structure of these porous precipitates constrain the site of their formation to above the sediment-water interface where metalliferous hydrothermal fluids vented into the overlying water column. These data constrain the geochemistry of the Mesoproterozoic sediment-water interface and the site of deposition for copper-cobalt-silver mineralization. Metals in the hydrothermal fluids titrated sulfide in seawater to create tortuous fluid-flow conduits. Pyrite that precipitated at the vent sites exhibits large sulfur isotope fractionation (>50‰), which indicates a close association between the vents and sulfate-reducing microbiota. In the subsurface, base metal sulfides precipitated from sulfide formed during the reduction of early diagenetic barite, also ultimately derived from seawater. This model suggests dynamic bottom-water redox conditions at the vent site driven by the interplay between sulfate-reducing organisms and metalliferous fluid effluence

Multi-ancestry GWAS reveals excitotoxicity associated with outcome after ischaemic stroke

During the first hours after stroke onset, neurological deficits can be highly unstable: some patients rapidly improve, while others deteriorate. This early neurological instability has a major impact on long-term outcome. Here, we aimed to determine the genetic architecture of early neurological instability measured by the difference between the National Institutes of Health Stroke Scale (NIHSS) within 6 h of stroke onset and NIHSS at 24 h. A total of 5876 individuals from seven countries (Spain, Finland, Poland, USA, Costa Rica, Mexico and Korea) were studied using a multi-ancestry meta-analyses. We found that 8.7% of NIHSS at 24 h of variance was explained by common genetic variations, and also that early neurological instability has a different genetic architecture from that of stroke risk. Eight loci (1p21.1, 1q42.2, 2p25.1, 2q31.2, 2q33.3, 5q33.2, 7p21.2 and 13q31.1) were genome-wide significant and explained 1.8% of the variability suggesting that additional variants influence early change in neurological deficits. We used functional genomics and bioinformatic annotation to identify the genes driving the association from each locus. Expression quantitative trait loci mapping and summary data-based Mendelian randomization indicate that ADAM23 (log Bayes factor = 5.41) was driving the association for 2q33.3. Gene-based analyses suggested that GRIA1 (log Bayes factor = 5.19), which is predominantly expressed in the brain, is the gene driving the association for the 5q33.2 locus. These analyses also nominated GNPAT (log Bayes factor = 7.64) ABCB5 (log Bayes factor = 5.97) for the 1p21.1 and 7p21.1 loci. Human brain single-nuclei RNA-sequencing indicates that the gene expression of ADAM23 and GRIA1 is enriched in neurons. ADAM23, a presynaptic protein and GRIA1, a protein subunit of the AMPA receptor, are part of a synaptic protein complex that modulates neuronal excitability. These data provide the first genetic evidence in humans that excitotoxicity may contribute to early neurological instability after acute ischaemic stroke. Ibanez et al. perform a multi-ancestry meta-analysis to investigate the genetic architecture of early stroke outcomes. Two of the eight genome-wide significant loci identified-ADAM23 and GRIA1-are involved in synaptic excitability, suggesting that excitotoxicity contributes to neurological instability after ischaemic stroke.Peer reviewe

ARIA 2016 : Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease.Peer reviewe

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Gut Microbiota, and Management of American Bison (Bison bison) in Conservation and Commercial Herds of the Great Plains

Because American bison (Bison bison) are important to both conservation and ranching, I inquired as to the diet and gut microbiota of these animals, and the implications of these factors for sound management. I found that bison in Kansas browsed more in spring and fall, and consumed more forbs during summer, but graminoids formed a consistently low proportion of the diet. In Colorado, the bison diet was dominated by graminoids, followed by forbs, then browse. This pattern remained consistent for 18 months, despite a brief increase in forbs and decrease in graminoids when the herd’s pasture was enlarged. Comparisons among sites from May-August showed significant differences, with bison in Montana and Kansas consuming more forbs and browse than those in Colorado during certain months. Thus, the diet of bison was temporospatially variable and sometimes deviated significantly from grazing, possibly due to 1) plants that are high in protein and low in toxins; 2) large body size dictating less forage selectivity; 3) a lack migration; and 4) broad niche breadth. The present study suggests that bison may benefit from access to forbs and browse in addition to grasses. I also compared gut microbiota along the digestive tract between grass-finished and grain-finished bison. Location had the greatest effect, with sections of the foregut, the hindgut, and to a lesser degree the midgut being statistically similar. I also found a significant effect of diet on gut microbiota throughout the digestive tract, with the grain-finished bison exhibiting higher relative abundances of the bacterial phyla Firmicutes and Proteobacteria. Finally, my analysis of the natural and human history of the Great Plains shows that bison and other animals, as well as new energy sources, have the potential to foster both ecological and economic sustainability in the region to a greater degree than the system currently in place

A high-resolution record of early Paleozoic climate

The spatial coverage and temporal resolution of the Early Paleozoic paleoclimate record are limited, primarily due to the paucity of well-preserved skeletal material commonly used for oxygen-isotope paleothermometry. Bulk-rock δ¹⁸O datasets can provide broader coverage and higher resolution, but are prone to burial alteration. We assess the diagenetic character of two thick Cambro-Ordovician carbonate platforms with minimal to moderate burial by pairing clumped and bulk isotope analyses of micritic carbonates. Despite resetting of the clumped-isotope thermometer at both sites, our samples indicate relatively little change to their bulk δ¹⁸O due to low fluid exchange. Consequently, both sequences preserve temporal trends in δ¹⁸O. Motivated by this result, we compile a global suite of bulk rock δ¹⁸O data, stacking overlapping regional records to minimize diagenetic influences on overall trends. We find good agreement of bulk rock δ¹⁸O with brachiopod and conodont δ¹⁸O trends through time. Given evidence that the δ¹⁸O value of seawater has not evolved substantially through the Phanerozoic, we interpret this record as primarily reflecting changes in tropical, nearshore seawater temperatures and only moderately modified by diagenesis. Focusing on the samples with the most enriched, and thus likely least-altered, δ¹⁸O values, we reconstruct Late Cambrian warming, Early Ordovician extreme warmth, and cooling around the Early-Middle Ordovician boundary. Our record is consistent with models linking the Great Ordovician Biodiversification Event to cooling of previously very warm tropical oceans. In addition, our high-temporal-resolution record suggests previously unresolved transient warming and climate instability potentially associated with Late Ordovician tectonic events

Primary microfossiliferous chert in the Aptian Barra Velha Formation

The Barra Velha Formation and other Aptian pre‐salt deposits record the history of the proto‐Atlantic basin and the rifting of Gondwana. Studies have sought to characterize the depositional environment of the basin with a focus on carbonate fabrics and magnesium silicate clays. However, the water chemistry and fluid sources in the basin, the silica cycle, and how the basin evolved over time are not fully constrained. Additionally, current understanding of the microbiota that inhabited this basin is incomplete because microfossils have rarely been identified in pre‐salt deposits, especially on the Brazilian margin. This study describes authigenic chert in the Barra Velha Formation that preserves distinct, organic‐rich structures and textures. The petrographic relationships between the chert and carbonate suggest that both formed as authigenic phases, but their formation was temporally decoupled. These relationships and δ30Si and δ18O data suggest that chert post‐dates the formation and subsequent dissolution of the carbonates, and may have formed from a different fluid. By characterizing the chert–carbonate paragenesis and mechanism of chert formation, this study provides new insights into the fluid sources and complexity of the basin. Together, the results of this research suggest that the chert precipitated as primary, authigenic phases after karstification of the carbonate from a newly introduced, low temperature, freshwater fluid that was chemically distinct from the lake water. The chert preserves organic matter that is compositionally and texturally distinct from the void‐filling bitumen associated with the classically studied carbonate facies. Based on the composition and morphologies of organic structures, this is likely primary organic matter and a morphologically diverse microfossil assemblage preserved in place at the time of chert formation. Thus, this early chert provides new insights into the water chemistry, fluid sources and silica cycle in the basin, and represents a unique taphonomic window that helps us characterize the pre‐salt basin microbiota