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  • Nature Publishing Group  (363,432)
  • Public Library of Science (PLoS)
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  • 1
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    Public Library of Science (PLoS)
    In:  EPIC3PLOS ONE, Public Library of Science (PLoS), 18(8), pp. e0290437-e0290437, ISSN: 1932-6203
    Publication Date: 2023-08-31
    Description: Due to its involvement in numerous feedbacks, sea ice plays a crucial role not only for polar climate but also at global scale. We analyse state-of-the-art observed, reconstructed, and modelled sea-ice concentration (SIC) together with sea surface temperature (SST) to disentangle the influence of different forcing factors on the variability of these coupled fields. Canonical Correlation Analysis provides distinct pairs of coupled Arctic SIC–Atlantic SST variability which are linked to prominent oceanic and atmospheric modes of variability over the period 1854–2017. The first pair captures the behaviour of the Atlantic meridional overturning circulation (AMOC) while the third and can be associated with the North Atlantic Oscillation (NAO) in a physically consistent manner. The dominant global SIC–Atlantic SST coupled mode highlights the contrast between the responses of Arctic and Antarctic sea ice to changes in AMOC over the 1959–2021 period. Model results indicate that coupled SST–SIC patterns can be associated with changes in ocean circulation. We conclude that a correct representation of AMOC-induced coupled SST–SIC variability in climate models is essential to understand the past, present and future sea-ice evolution.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 2
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    Public Library of Science (PLoS)
    In:  EPIC3PLOS ONE, Public Library of Science (PLoS), 18(7), pp. e0286036-e0286036, ISSN: 1932-6203
    Publication Date: 2023-08-01
    Description: Euphausia superba is a key species of the Southern Ocean, impacted by climate change and human exploitation. Understanding how these changes affect the distribution and abundance of krill is crucial for generating projections of change for Southern Ocean ecosystems. Krill growth is an important indicator of habitat suitability and a series of models have been developed and used to examine krill growth potential at different spatial and temporal scales. The available models have been developed using a range of empirical and mechanistic approaches, providing alternative perspectives and comparative analyses of the key processes influencing krill growth. Here we undertake an intercomparison of a suite of the available models to understand their sensitivities to major driving variables. This illustrates that the results are strongly determined by the model structure and technical characteristics, and the data on which they were developed and validated. Our results emphasize the importance of assessing the constraints and requirements of individual krill growth models to ensure their appropriate application. The study also demonstrates the value of the development of alternative modelling approaches to identify key processes affecting the dynamics of krill. Of critical importance for modelling the growth of krill is appropriately assessing and accounting for differences in estimates of food availability resulting from alternative methods of observation. We suggest that an intercomparison approach is particularly valuable in the development and application of models for the assessment of krill growth potential at circumpolar scales and for future projections. As another result of the intercomparison, the implementations of the models used in this study are now publicly available for future use and analyses.
    Repository Name: EPIC Alfred Wegener Institut
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  • 3
    Publication Date: 2024-02-28
    Description: The superfamily Orthalicoidea comprises approximately 2,000 species of terrestrial gastropods, mostly concentrated in the Neotropics but also present in southern Africa and Oceania. We provide a multi-marker molecular phylogeny of this superfamily, reassessing its \nfamily- and genus-level classification. We exclude two families from the group, Odontostomidae and Vidaliellidae, transferring them to Rhytidoidea based on their phylogenetic relationships as recovered herein. Two new families are recognized herein as members of \nOrthalicoidea, Tomogeridae and Cyclodontinidae fam. nov. The family Megaspiridae and \nthe subfamily Prestonellinae are paraphyletic but are retained herein for taxonomic stability. \nThe subfamily Placostylinae is synonymized with Bothriembryontinae. The new genera \nAlterorhinus gen. nov. and Sanniostracus gen. nov. containing some Brazilian species are \ndescribed here to better reflect the phylogeny. The fossil record and paleobiogeographic \nhistory of the group is explored under the new phylogenetic framework.
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
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  • 4
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    Public Library of Science (PLoS)
    In:  PLOS Computational Biology vol. 19 no. 10, pp. e1011541-e1011541
    Publication Date: 2024-03-12
    Description: Insect population numbers and biodiversity have been rapidly declining with time, and monitoring \nthese trends has become increasingly important for conservation measures to be \neffectively implemented. But monitoring methods are often invasive, time and resource \nintense, and prone to various biases. Many insect species produce characteristic sounds \nthat can easily be detected and recorded without large cost or effort. Using deep learning \nmethods, insect sounds from field recordings could be automatically detected and classified \nto monitor biodiversity and species distribution ranges. We implement this using recently \npublished datasets of insect sounds (up to 66 species of Orthoptera and Cicadidae) and \nmachine learning methods and evaluate their potential for acoustic insect monitoring. We \ncompare the performance of the conventional spectrogram-based audio representation \nagainst LEAF, a new adaptive and waveform-based frontend. LEAF achieved better classification \nperformance than the mel-spectrogram frontend by adapting its feature extraction \nparameters during training. This result is encouraging for future implementations of deep \nlearning technology for automatic insect sound recognition, especially as larger datasets \nbecome available.
    Repository Name: National Museum of Natural History, Netherlands
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  • 5
    Publication Date: 2024-04-09
    Description: Biodiversity loss is a major global challenge and minimizing extinction rates is the goal of several multilateral environmental agreements. Policy decisions require comprehensive, spatially explicit information on species’ distributions and threats. We present an analysis of the conservation status of 14,669 European terrestrial, freshwater and marine species (ca. 10% of the continental fauna and flora), including all vertebrates and selected groups of invertebrates and plants. Our results reveal that 19% of European species are threatened with extinction, with higher extinction risks for plants (27%) and invertebrates (24%) compared to vertebrates (18%). These numbers exceed recent IPBES (Intergovernmental Platform on Biodiversity and Ecosystem Services) assumptions of extinction risk. Changes in agricultural practices and associated habitat loss, overharvesting, pollution and development are major threats to biodiversity. Maintaining and restoring sustainable land and water use practices is crucial to minimize future biodiversity declines.
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
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  • 6
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    Nature Publishing Group
    In:  EPIC3Nature Climate Change, Nature Publishing Group, 12(3), pp. 249-255
    Publication Date: 2022-06-20
    Repository Name: EPIC Alfred Wegener Institut
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  • 7
    Publication Date: 2022-08-11
    Description: The methanogenic degradation of oil hydrocarbons can proceed through syntrophic partnerships of hydrocarbon-degrading bacteria and methanogenic archaea1,2,3. However, recent culture-independent studies have suggested that the archaeon ‘Candidatus Methanoliparum’ alone can combine the degradation of long-chain alkanes with methanogenesis4,5. Here we cultured Ca. Methanoliparum from a subsurface oil reservoir. Molecular analyses revealed that Ca. Methanoliparum contains and overexpresses genes encoding alkyl-coenzyme M reductases and methyl-coenzyme M reductases, the marker genes for archaeal multicarbon alkane and methane metabolism. Incubation experiments with different substrates and mass spectrometric detection of coenzyme-M-bound intermediates confirm that Ca. Methanoliparum thrives not only on a variety of long-chain alkanes, but also on n-alkylcyclohexanes and n-alkylbenzenes with long n-alkyl (C≥13) moieties. By contrast, short-chain alkanes (such as ethane to octane) or aromatics with short alkyl chains (C≤12) were not consumed. The wide distribution of Ca. Methanoliparum4,5,6 in oil-rich environments indicates that this alkylotrophic methanogen may have a crucial role in the transformation of hydrocarbons into methane.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 8
    Publication Date: 2023-06-21
    Description: Multiomics approaches need to be applied in the central Arctic Ocean to benchmark biodiversity change and to identify novel species and their genes. As part of MOSAiC, EcoOmics will therefore be essential for conservation and sustainable bioprospecting in one of the least explored ecosystems on Earth.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 9
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    Public Library of Science (PLoS)
    In:  EPIC3PLOS ONE, Public Library of Science (PLoS), 17(9), pp. e0273623-e0273623, ISSN: 1932-6203
    Publication Date: 2023-10-23
    Description: While the output of a team is evident, the productivity of each team member is typically not readily identifiable. In this paper we consider the problem of measuring the productivity of team members. We propose a new concept of coworker productivity, which we refer to as eigenvalue productivity (EVP). We demonstrate the existence and uniqueness of our concept and show that it possesses several desirable properties. Also, we suggest a procedure for specifying the required productivity matrix of a team, and illustrate the operational practicability of EVP by means of three examples representing different types of available data.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 10
    Publication Date: 2022-10-31
    Description: The statistical properties of seismicity are known to be affected by several factors such as the rheological parameters of rocks. We analysed the earthquake double-couple as a function of the faulting type. Here we show that it impacts the moment tensors of earthquakes: thrust- faulting events are characterized by higher double-couple components with respect to strike- slip- and normal-faulting earthquakes. Our results are coherent with the stress dependence of the scaling exponent of the Gutenberg-Richter law, which is anticorrelated to the double- couple. We suggest that the structural and tectonic control of seismicity may have its origin in the complexity of the seismogenic source marked by the width of the cataclastic damage zone and by the slip of different fault planes during the same seismic event; the sharper and concentrated the slip as along faults, the higher the double-couple. This phenomenon may introduce bias in magnitude estimation, with possible impact on seismic forecasting.
    Description: Published
    Description: 258
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: double couple ; damage zone ; different fault type ; seismicity ; tectonics ; fault type ; seismicity ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2021-02-03
    Description: The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today; in the Atlantic basin, deep waters of Southern Ocean origin increased in volume while above them the core of the North Atlantic Deep Water (NADW) shoaled. An absence of evidence on the origin of this phenomenon means that the sequence of events leading to global glacial conditions remains unclear. Here we present multi-proxy evidence showing that northward shifts in Antarctic iceberg melt in the Indian–Atlantic Southern Ocean (0–50°E) systematically preceded deep-water mass reorganizations by one to two thousand years during Pleistocene-era glaciations. With the aid of iceberg-trajectory model experiments, we demonstrate that such a shift in iceberg trajectories during glacial periods can result in a considerable redistribution of freshwater in the Southern Ocean. We suggest that this, in concert with increased sea-ice cover, enabled positive buoyancy anomalies to ‘escape’ into the upper limb of the AMOC, providing a teleconnection between surface Southern Ocean conditions and the formation of NADW. The magnitude and pacing of this mechanism evolved substantially across the mid-Pleistocene transition, and the coeval increase in magnitude of the ‘southern escape’ and deep circulation perturbations implicate this mechanism as a key feedback in the transition to the ‘100-kyr world’, in which glacial–interglacial cycles occur at roughly 100,000-year periods.
    Repository Name: EPIC Alfred Wegener Institut
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  • 12
    Publication Date: 2021-10-20
    Description: Coastal sands are biocatalytic filters for dissolved and particulate organic matter of marine and terrestrial origin, thus, acting as centers of organic matter transformation. At high temporal resolution, we accessed the variability of benthic bacterial communities over two annual cycles at Helgoland (North Sea), and compared it with seasonality of communities in Isfjorden (Svalbard, 78°N) sediments, where primary production does not occur during winter. Benthic community structure remained stable in both, temperate and polar sediments on the level of cell counts and 16S rRNA-based taxonomy. Actinobacteriota of uncultured Actinomarinales and Microtrichales were a major group, with 8 ± 1% of total reads (Helgoland) and 31 ± 6% (Svalbard). Their high activity (frequency of dividing cells 28%) and in situ cell numbers of 〉10% of total microbes in Svalbard sediments, suggest Actinomarinales and Microtrichales as key heterotrophs for carbon mineralization. Even though Helgoland and Svalbard sampling sites showed no phytodetritus-driven changes of the benthic bacterial community structure, they harbored significantly different communities (p 〈 0.0001, r = 0.963). The temporal stability of benthic bacterial communities is in stark contrast to the dynamic succession typical of coastal waters, suggesting that pelagic and benthic bacterial communities respond to phytoplankton productivity very differently.
    Repository Name: EPIC Alfred Wegener Institut
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  • 13
    Publication Date: 2022-08-15
    Description: Anaerobic oxidation of ammonium (anammox) in oxygen minimum zones (OMZs) is a major pathway of oceanic nitrogen loss. Ammonium released from sinking particles has been suggested to fuel this process. During cruises to the Peruvian OMZ in April–June 2017 we found that anammox rates are strongly correlated with the volume of small particles (128–512 µm), even though anammox bacteria were not directly associated with particles. This suggests that the relationship between anammox rates and particles is related to the ammonium released from particles by remineralization. To investigate this, ammonium release from particles was modelled and theoretical encounters of free-living anammox bacteria with ammonium in the particle boundary layer were calculated. These results indicated that small sinking particles could be responsible for ~75% of ammonium release in anoxic waters and that free-living anammox bacteria frequently encounter ammonium in the vicinity of smaller particles. This indicates a so far underestimated role of abundant, slow-sinking small particles in controlling oceanic nutrient budgets, and furthermore implies that observations of the volume of small particles could be used to estimate N-loss across large areas.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 14
    Publication Date: 2020-04-14
    Description: The Asian monsoon (AM) played an important role in the dynastic history of China, yet it remains unknown whether AM-mediated shifts in Chinese societies affect earth surface processes to the point of exceeding natural variability. Here, we present a dust storm intensity record dating back to the first unified dynasty of China (the Qin Dynasty, 221–207 B.C.E.). Marked increases in dust storm activity coincided with unified dynasties with large populations during strong AM periods. By contrast, reduced dust storm activity corresponded to decreased population sizes and periods of civil unrest, which was co-eval with a weakened AM. The strengthened AM may have facilitated the development of Chinese civilizations, destabilizing the topsoil and thereby increasing the dust storm frequency. Beginning at least 2000 years ago, human activities might have started to overtake natural climatic variability as the dominant controls of dust storm activity in eastern China.
    Repository Name: EPIC Alfred Wegener Institut
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  • 15
    Publication Date: 2020-11-12
    Description: Antarctic krill, Euphausia superba, supports a valuable commercial fishery in the Southwest Atlantic, which holds the highest krill densities and is warming rapidly. The krill catch is increasing, is concentrated in a small area, and has shifted seasonally from summer to autumn/winter. The fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources, with the main goal of safeguarding the large populations of krill-dependent predators. Here we show that, because of the restricted distribution of successfully spawning krill and high inter-annual variability in their biomass, the risk of direct fishery impacts on the krill stock itself might be higher than previously thought. We show how management benefits could be achieved by incorporating uncertainty surrounding key aspects of krill ecology into management decisions, and how knowledge can be improved in these key areas. This improved information may be supplied, in part, by the fishery itself.
    Repository Name: EPIC Alfred Wegener Institut
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  • 16
    Publication Date: 2022-06-20
    Description: Between 2003-2016, the Greenland ice sheet (GrIS) was one of the largest contributors to sea level rise, as it lost about 255 Gt of ice per year. This mass loss slowed in 2017 and 2018 to about 100 Gt yr−1. Here we examine further changes in rate of GrIS mass loss, by analyzing data from the GRACE-FO (Gravity Recovery and Climate Experiment – Follow On) satellite mission, launched in May 2018. Using simulations with regional climate models we show that the mass losses observed in 2017 and 2018 by the GRACE and GRACE-FO missions are lower than in any other two year period between 2003 and 2019, the combined period of the two missions. We find that this reduced ice loss results from two anomalous cold summers in western Greenland, compounded by snow-rich autumn and winter conditions in the east. For 2019, GRACE-FO reveals a return to high melt rates leading to a mass loss of 223 ± 12 Gt month−1 during the month of July alone, and a record annual mass loss of 532 ± 58 Gt yr−1.
    Repository Name: EPIC Alfred Wegener Institut
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  • 17
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    Public Library of Science (PLoS)
    In:  EPIC3PLOS ONE, Public Library of Science (PLoS), 15(8), pp. e0237704-e0237704, ISSN: 1932-6203
    Publication Date: 2023-06-21
    Description: Since plastics degrade very slowly, they remain in the environment on much longer timescales than most natural organic substrates and provide a novel habitat for colonization by bacterial communities. The spectrum of relationships between plastics and bacteria, however, is little understood. The first objective of this study was to examine plastics as substrates for communities of Bacteria in estuarine surface waters. We used next-generation sequencing of the 16S rRNA gene to characterize communities from plastics collected in the field, and over the course of two colonization experiments, from biofilms that developed on plastic (low-density polyethylene, high-density polyethylene, polypropylene, polycarbonate, polystyrene) and glass substrates placed in the environment. Both field sampling and colonization experiments were conducted in estuarine tributaries of the lower Chesapeake Bay. As a second objective, we concomitantly analyzed biofilms on plastic substrates to ascertain the presence and abundance of Vibrio spp. bacteria, then isolated three human pathogens, V. cholerae, V. parahaemolyticus, and V. vulnificus, and determined their antibiotic-resistant profiles. In both components of this study, we compared our results with analyses conducted on paired samples of estuarine water. This research adds to a nascent literature that suggests environmental factors govern the development of bacterial communities on plastics, more so than the characteristics of the plastic substrates themselves. In addition, this study is the first to culture three pathogenic vibrios from plastics in estuaries, reinforcing and expanding upon earlier reports of plastic pollution as a habitat for Vibrio species. The antibiotic resistance detected among the isolates, coupled with the longevity of plastics in the aqueous environment, suggests biofilms on plastics have potential to persist and serve as focal points of potential pathogens and horizontal gene transfer.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 18
    Publication Date: 2021-01-12
    Description: Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across permafrost regions for the period since the International Polar Year (2007–2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous permafrost zone increased by 0.39 ± 0.15 °C. Over the same period, discontinuous permafrost warmed by 0.20 ± 0.10 °C. Permafrost in mountains warmed by 0.19 ± 0.05 °C and in Antarctica by 0.37 ± 0.10 °C. Globally, permafrost temperature increased by 0.29 ± 0.12 °C. The observed trend follows the Arctic amplification of air temperature increase in the Northern Hemisphere. In the discontinuous zone, however, ground warming occurred due to increased snow thickness while air temperature remained statistically unchanged.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
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  • 19
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    Nature Publishing Group
    In:  EPIC3Scientific Reports, Nature Publishing Group, 9(7962), ISSN: 2045-2322
    Publication Date: 2019-06-11
    Description: Arctic warming was more pronounced than warming in midlatitudes in the last decades making this region a hotspot of climate change. Associated with this, a rapid decline of sea-ice extent and a decrease of its thickness has been observed. Sea-ice retreat allows for an increased transport of heat and momentum from the ocean up to the tropo- and stratosphere by enhanced upward propagation of planetary-scale atmospheric waves. In the upper atmosphere, these waves deposit the momentum transported, disturbing the stratospheric polar vortex, which can lead to a breakdown of this circulation with the potential to also significantly impact the troposphere in mid- to late-winter and early spring. Therefore, an accurate representation of stratospheric processes in climate models is necessary to improve the understanding of the impact of retreating sea ice on the atmospheric circulation. By modeling the atmospheric response to a prescribed decline in Arctic sea ice, we show that including interactive stratospheric ozone chemistry in atmospheric model calculations leads to an improvement in tropo-stratospheric interactions compared to simulations without interactive chemistry. This suggests that stratospheric ozone chemistry is important for the understanding of sea ice related impacts on atmospheric dynamics.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
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  • 20
    Publication Date: 2019-07-15
    Description: The oxygen isotope composition of speleothems is a widely used proxy for past climate change. Robust use of this proxy depends on understanding the relationship between precipitation and cave drip water δ18O. Here, we present the first global analysis, based on data from 163 drip sites, from 39 caves on five continents, showing that drip water δ18O is most similar to the amount-weighted precipitation δ18O where mean annual temperature (MAT) is 〈 10 °C. By contrast, for seasonal climates with MAT 〉 10 °C and 〈 16 °C, drip water δ18O records the recharge-weighted δ18O. This implies that the δ18O of speleothems (formed in near isotopic equilibrium) are most likely to directly reflect meteoric precipitation in cool climates only. In warmer and drier environments, speleothems will have a seasonal bias toward the precipitation δ18O of recharge periods and, in some cases, the extent of evaporative fractionation of stored karst water.
    Repository Name: EPIC Alfred Wegener Institut
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  • 21
    Publication Date: 2020-01-21
    Description: Stable water isotopes are employed as hydrological tracers to quantify the diverse implications of atmospheric moisture for climate. They are widely used as proxies for studying past climate changes, e.g., in isotope records from ice cores and speleothems. Here, we present a new isotopic dataset of both near-surface vapour and ocean surface water from the North Pole to Antarctica, continuously measured from a research vessel throughout the Atlantic and Arctic Oceans during a period of two years. Our observations contribute to a better understanding and modelling of water isotopic composition. The observations reveal that the vapour deuterium excess within the atmospheric boundary layer is not modulated by wind speed, contrary to the commonly used theory, but controlled by relative humidity and sea surface temperature only. In sea ice covered regions, the sublimation of deposited snow on sea ice is a key process controlling the local water vapour isotopic composition.
    Repository Name: EPIC Alfred Wegener Institut
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  • 22
    Publication Date: 2022-06-20
    Description: Time-resolved satellite gravimetry has revolutionized understanding of mass transport in the Earth system. Since 2002, the Gravity Recovery and Climate Experiment (GRACE) has enabled monitoring of the terrestrial water cycle, ice sheet and glacier mass balance, sea level change and ocean bottom pressure variations, as well as understanding responses to changes in the global climate system. Initially a pioneering experiment of geodesy, the time-variable observations have matured into reliable mass transport products, allowing assessment and forecast of a number of important climate trends, and improvements in service applications such as the United States Drought Monitor. With the successful launch of the GRACE Follow-On mission, a multi-decadal record of mass variability in the Earth system is within reach.
    Repository Name: EPIC Alfred Wegener Institut
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  • 23
    Publication Date: 2022-01-31
    Description: Aquatic ecosystems worldwide continue to experience unprecedented warming and ecological change. Warming increases metabolic rates of animals, plants, and microbes, accelerating their use of energy and materials, their population growth, and interaction rates. At a much larger biological scale, warming accelerates ecosystem-level processes, elevating fluxes of carbon and oxygen between biota and the atmosphere. Although these general effects of temperature at finer and broader biological scales are widely observed, they can lead to contradictory predictions for how warming affects the structure and function of ecological communities at the intermediate scale of biological organization. We experimentally tested the hypothesis that the presence of predators and their associated species interactions modify the temperature dependence of net ecosystem oxygen production and respiration. We tracked a series of independent freshwater ecosystems (370 L) over 9 weeks, and we found that at higher temperatures, cascading effects of predators on zooplankton prey and algae were stronger than at lower temperatures. When grazing was weak or absent, standing phytoplankton biomass declined by 85%–95% (〈1-fold) over the temperature gradient (19–30 °C), and by 3-fold when grazers were present and lacked predators. These temperature-dependent species interactions and consequent community biomass shifts occurred without signs of species loss or community collapse, and only modestly affected the temperature dependence of net ecosystem oxygen fluxes. The exponential increases in net ecosystem oxygen production and consumption were relatively insensitive to differences in trophic interactions among ecosystems. Furthermore, monotonic declines in phytoplankton standing stock suggested no threshold effects of warming across systems. We conclude that local changes in community structure, including temperature-dependent trophic cascades, may be compatible with prevailing and predictable effects of temperature on ecosystem functions related to fundamental effects of temperature on metabolism.
    Type: Article , PeerReviewed
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  • 24
    Publication Date: 2023-03-09
    Description: Almost all animals and plants are inhabited by diverse communities of microorganisms, the microbiota, thereby forming an integrated entity, the metaorganism. Natural selection should favor hosts that shape the community composition of these microbes to promote a beneficial host-microbe symbiosis. Indeed, animal hosts often pose selective environments, which only a subset of the environmentally available microbes are able to colonize. How these microbes assemble after colonization to form the complex microbiota is less clear. Neutral models are based on the assumption that the alternatives in microbiota community composition are selectively equivalent and thus entirely shaped by random population dynamics and dispersal. Here, we use the neutral model as a null hypothesis to assess microbiata composition in host organisms, which does not rely on invoking any adaptive processes underlying microbial community assembly. We show that the overall microbiota community structure from a wide range of host organisms, in particular including previously understudied invertebrates, is in many cases consistent with neutral expectations. Our approach allows to identify individual microbes that are deviating from the neutral expectation and are therefore interesting candidates for further study. Moreover, using simulated communities, we demonstrate that transient community states may play a role in the deviations from the neutral expectation. Our findings highlight that the consideration of neutral processes and temporal changes in community composition are critical for an in-depth understanding of microbiota-host interactions.
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  • 25
    Publication Date: 2018-09-20
    Description: Understanding how the Antarctic ice sheet will respond to global warming relies on knowledge of how it has behaved in the past. The use of numerical models, the only means to quantitatively predict the future, is hindered by limitations to topographic data both now and in the past, and in knowledge of how subsurface oceanic, glaciological and hydrological processes interact. Incorporating the variety and interplay of such processes, operating at multiple spatio-temporal scales, is critical to modeling the Antarctic’s system evolution and requires direct observations in challenging locations. As these processes do not observe disciplinary boundaries neither should our future research.
    Repository Name: EPIC Alfred Wegener Institut
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  • 26
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    Nature Publishing Group
    In:  EPIC3Nature Communication, Nature Publishing Group, 9(3178), ISSN: 2041-1723
    Publication Date: 2019-02-13
    Description: Natural dissolved organic matter (DOM) comprises a broad range of dissolved organic molecules in aquatic systems and is among the most complex molecular mixtures known. Here we show, by comparing detailed structural fingerprints of individual molecular formulae in DOM from a set of four marine and one freshwater environments, that a major component of DOM is molecularly indistinguishable in these diverse samples. Molecular conformity was not only apparent by the co-occurrence of thousands of identical molecular formulae, but also by identical structural features of those isomers that collectively represent a molecular formula. The presence of a large pool of compounds with identical structural features in DOM is likely the result of a cascade of degradation processes or common synthetic pathways that ultimately lead to the formation of a universal background, regardless of origin and history of the organic material. This novel insight impacts our understanding of long-term turnover of DOM as the underlying mechanisms are possibly universal.
    Repository Name: EPIC Alfred Wegener Institut
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  • 27
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    Nature Publishing Group
    In:  EPIC3Nature Protocols, Nature Publishing Group, 13(6), pp. 1310-1330, ISSN: 1754-2189
    Publication Date: 2020-02-23
    Description: Traditionally, the description of microorganisms starts with their isolation from an environmental sample. Many environmentally relevant anaerobic microorganisms grow very slowly, and often they rely on syntrophic interactions with other microorganisms. This impedes their isolation and characterization by classic microbiological techniques. We developed and applied an approach for the successive enrichment of syntrophic hydrocarbon-degrading microorganisms from environmental samples. We collected samples from microbial mat-covered hydrothermally heated hydrocarbon-rich sediments of the Guaymas Basin and mixed them with synthetic mineral medium to obtain sediment slurries. Supplementation with defined substrates (i.e., methane or butane), incubation at specific temperatures, and a regular maintenance procedure that included the measurement of metabolic products and stepwise dilutions enabled us to establish highly active, virtually sediment-free enrichment cultures of actively hydrocarbon-degrading communities in a 6-months to several-years' effort. Using methane as sole electron donor shifted the originally highly diverse microbial communities toward defined mixed cultures dominated by syntrophic consortia consisting of anaerobic methane-oxidizing archaea (ANME) and different sulfate-reducing bacteria. Cultivation with butane at 50 °C yielded consortia of archaea belonging to Candidatus Syntrophoarchaeum and Candidatus Desulfofervidus auxilii partner bacteria. This protocol also describes sampling for further molecular characterization of enrichment cultures by fluorescence in situ hybridization (FISH), and transcriptomics and metabolite analyses, which can provide insights into the functioning of hydrocarbon metabolism in archaea and resolve important mechanisms that enable electron transfer to their sulfate-reducing partner bacteria.
    Repository Name: EPIC Alfred Wegener Institut
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    Publication Date: 2020-02-12
    Description: The construction of high capacity data sharing networks to support increasing government and commercial data exchange has highlighted a key roadblock: the content of existing Internet-connected information remains siloed due to a multiplicity of local languages and data dictionaries. This lack of a digital lingua franca is obvious in the domain of human food as materials travel from their wild or farm origin, through processing and distribution chains, to consumers. Well defined, hierarchical vocabulary, connected with logical relationships—in other words, an ontology—is urgently needed to help tackle data harmonization problems that span the domains of food security, safety, quality, production, distribution, and consumer health and convenience. FoodOn (http://foodon.org) is a consortium-driven project to build a comprehensive and easily accessible global farm-to-fork ontology about food, that accurately and consistently describes foods commonly known in cultures from around the world. FoodOn addresses food product terminology gaps and supports food traceability. Focusing on human and domesticated animal food description, FoodOn contains animal and plant food sources, food categories and products, and other facets like preservation processes, contact surfaces, and packaging. Much of FoodOn’s vocabulary comes from transforming LanguaL, a mature and popular food indexing thesaurus, into a World Wide Web Consortium (W3C) OWL Web Ontology Language-formatted vocabulary that provides system interoperability, quality control, and software-driven intelligence. FoodOn compliments other technologies facilitating food traceability, which is becoming critical in this age of increasing globalization of food networks.
    Repository Name: EPIC Alfred Wegener Institut
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 1287, doi:10.1038/s41467-018-03468-6.
    Description: Warm subtropical-origin Atlantic water flows northward across the Greenland-Scotland Ridge into the Nordic Seas, where it relinquishes heat to the atmosphere and gradually transforms into dense Atlantic-origin water. Returning southward along east Greenland, this water mass is situated beneath a layer of cold, fresh surface water and sea ice. Here we show, using measurements from autonomous ocean gliders, that the Atlantic-origin water was re-ventilated while transiting the western Iceland Sea during winter. This re-ventilation is a recent phenomenon made possible by the retreat of the ice edge toward Greenland. The fresh surface layer that characterises this region in summer is diverted onto the Greenland shelf by enhanced onshore Ekman transport induced by stronger northerly winds in fall and winter. Severe heat loss from the ocean offshore of the ice edge subsequently triggers convection, which further transforms the Atlantic-origin water. This re-ventilation is a counterintuitive occurrence in a warming climate, and highlights the difficulties inherent in predicting the behaviour of the complex coupled climate system.
    Description: Support for this work was provided by the Norwegian Research Council under Grant agreement no. 231647 (L.H. and K.V.), the Bergen Research Foundation under Grant BFS2016REK01 (K.V.), and the Centre for Climate Dynamics at the Bjerknes Centre through the FRESHWATER project (K.V.). Additional funding was provided by the Swiss National Science Foundation grants P2EZP2162267 and P300P2174307 (L.P.), the National Science Foundation grant OCE-1558742 (M.A.S.), the Norway Fulbright Foundation (K.V.), the Canada Fulbright Foundation (G.W.K.M.), and the Natural Sciences and Engineering Research Council of Canada (G.W.K.M.).
    Repository Name: Woods Hole Open Access Server
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 4917, doi:10.1038/s41598-018-23167-y.
    Description: Intertidal inhabitants are exposed to the 24-hour solar day, and the 12.4 hour rising and falling of the tides. One or both of these cycles govern intertidal organisms’ behaviour and physiology, yet little is known about the molecular clockworks of tidal rhythmicity. Here, we show that the limpet Cellana rota exhibits robust tidally rhythmic behaviour and gene expression. We assembled a de-novo transcriptome, identifying novel tidal, along with known circadian clock genes. Surprisingly, most of the putative circadian clock genes, lack a typical rhythmicity. We identified numerous tidally rhythmic genes and pathways commonly associated with the circadian clock. We show that not only is the behaviour of an intertidal organism in tune with the tides, but so too are many of its genes and pathways. These findings highlight the plasticity of biological timekeeping in nature, strengthening the growing notion that the role of ‘canonical’ circadian clock genes may be more fluid than previously thought, as exhibited in an organism which has evolved in an environment where tidal oscillations are the dominant driving force.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 8128, doi:10.1038/s41598-018-26484-4.
    Description: The kakapo is a critically endangered, herbivorous parrot endemic to New Zealand. The kakapo hindgut hosts a dense microbial community of low taxonomic diversity, typically dominated by Escherichia fergusonii, and has proven to be a remarkably stable ecosystem, displaying little variation in core membership over years of study. To elucidate mechanisms underlying this robustness, we performed 16S rRNA gene-based co-occurrence network analysis to identify potential interactions between E. fergusonii and the wider bacterial community. Genomic and metagenomic sequencing were employed to facilitate interpretation of potential interactions observed in the network. E. fergusonii maintained very few correlations with other members of the microbiota, and isolates possessed genes for the generation of energy from a wide range of carbohydrate sources, including plant fibres such as cellulose. We surmise that this dominant microorganism is abundant not due to ecological interaction with other members of the microbiota, but its ability to metabolise a wide range of nutrients in the gut. This research represents the first concerted effort to understand the functional roles of the kakapo microbiota, and leverages metagenomic data to contextualise co-occurrence patterns. By combining these two techniques we provide a means for studying the diversity-stability hypothesis in the context of bacterial ecosystems.
    Description: This work was supported by funding from the Department of Conservation (DOC) as well as a University of Auckland Faculty Research Development Fund grant (9841 3626187) to MWT, and a University of Auckland Doctoral Scholarship to DWW.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 7363, doi:10.1038/s41598-018-25565-8.
    Description: Satellite-tracking of mature white sharks (Carcharodon carcharias) has revealed open-ocean movements spanning months and covering tens of thousands of kilometers. But how are the energetic demands of these active apex predators met as they leave coastal areas with relatively high prey abundance to swim across the open ocean through waters often characterized as biological deserts? Here we investigate mesoscale oceanographic variability encountered by two white sharks as they moved through the Gulf Stream region and Sargasso Sea in the North Atlantic Ocean. In the vicinity of the Gulf Stream, the two mature female white sharks exhibited extensive use of the interiors of clockwise-rotating anticyclonic eddies, characterized by positive (warm) temperature anomalies. One tagged white shark was also equipped with an archival tag that indicated this individual made frequent dives to nearly 1,000 m in anticyclones, where it was presumably foraging on mesopelagic prey. We propose that warm temperature anomalies in anticyclones make prey more accessible and energetically profitable to adult white sharks in the Gulf Stream region by reducing the physiological costs of thermoregulation in cold water. The results presented here provide valuable new insight into open ocean habitat use by mature, female white sharks that may be applicable to other large pelagic predators.
    Description: This work was supported by the WHOI Ocean Life Institute and awards from NASA and NSF.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2398, doi:10.1038/s41467-018-04809-1.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 10610, doi:10.1038/s41598-018-28871-3.
    Description: Foraminifera in sediments exposed to gas-hydrate dissociation are not expected to have cellular adaptations that facilitate inhabitation of chemosynthesis-based ecosystems because, to date, there are no known endemic seep foraminifera. To establish if foraminifera inhabit sediments impacted by gas-hydrate dissociation, we examined the cellular ultrastructure of Melonis barleeanus (Williamson, 1858) from the Vestnesa gas hydrate province (Arctic Ocean, west of Svalbard at ~79 °N; ~1200-m depth; n = 4). From sediments with gas hydrate indicators, living M. barleeanus had unusual pore plugs composed of a thick, fibrous meshwork; mitochondria were concentrated at the cell periphery, under pore plugs. While there was no evidence of endosymbioses with prokaryotes, most M. barleeanus specimens were associated with what appear to be Type I methanotrophic bacteria. One foraminifer had a particularly large bolus of these microbes concentrated near its aperture. This is the first documented instance of bona fide living M. barleeanus in gas-hydrate sediments and first documentation of a foraminifer living in close association with putative methanotrophs. Our observations have implications to paleoclimate records utilizing this foundational foraminiferal species.
    Description: JMB was funded by a WHOI Independent Study Award (Mellon Grant), with partial support from NSF grant OCE-1634469. GP and CAGE 15-2 cruise were supported by the Research Council of Norway through CAGE Center for Excellence in Arctic Gas Hydrate Environment and Climate project 223259 and NORCRUST (project number 255150).
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2809, doi:10.1038/s41467-018-05253-x.
    Description: Voltage-sensing (VSD) and cyclic nucleotide-binding domains (CNBD) gate ion channels for rapid electrical signaling. By contrast, solute carriers (SLCs) that passively redistribute substrates are gated by their substrates themselves. Here, we study the orphan sperm-specific solute carriers SLC9C1 that feature a unique tripartite structure: an exchanger domain, a VSD, and a CNBD. Voltage-clamp fluorimetry shows that SLC9C1 is a genuine Na+/H+ exchanger gated by voltage. The cellular messenger cAMP shifts the voltage range of activation. Mutations in the transport domain, the VSD, or the CNBD strongly affect Na+/H+ exchange, voltage gating, or cAMP sensitivity, respectively. Our results establish SLC9C1 as a phylogenetic chimaera that combines the ion-exchange mechanism of solute carriers with the gating mechanism of ion channels. Classic SLCs slowly readjust changes in the intra- and extracellular milieu, whereas voltage gating endows the Na+/H+ exchanger with the ability to produce a rapid pH response that enables downstream signaling events.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 14955, doi:10.1038/s41598-018-33021-w.
    Description: Glomeruli are the functional units of olfactory information processing but little remains known about their individual unit function. This is due to their widespread activation by odor stimuli. We expressed channelrhodopsin-2 in a single olfactory sensory neuron type, and used laser stimulation and simultaneous in vivo calcium imaging to study the responses of a single glomerulus to optogenetic stimulation. Calcium signals in the neuropil of this glomerulus were representative of the sensory input and nearly identical if evoked by intensity-matched odor and laser stimuli. However, significantly fewer glomerular layer interneurons and olfactory bulb output neurons (mitral cells) responded to optogenetic versus odor stimuli, resulting in a small and spatially compact optogenetic glomerular unit response. Temporal features of laser stimuli were represented with high fidelity in the neuropil of the glomerulus and the mitral cells, but not in interneurons. Increases in laser stimulus intensity were encoded by larger signal amplitudes in all compartments of the glomerulus, and by the recruitment of additional interneurons and mitral cells. No spatial expansion of the glomerular unit response was observed in response to stronger input stimuli. Our data are among the first descriptions of input-output transformations in a selectively activated olfactory glomerulus.
    Description: Funded by the World Class Institute/National Research Foundation of Korea (KRF: WCI 2009-003) and NIH: DC005259 and NS099691 grants.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 15517, doi:10.1038/s41598-018-33610-9.
    Description: Subduction zones impose an important control on the geochemical cycling between the surficial and internal reservoirs of the Earth. Sulphur and carbon are transferred into Earth’s mantle by subduction of pelagic sediments and altered oceanic lithosphere. Release of oxidizing sulphate- and carbonate-bearing fluids modifies the redox state of the mantle and the chemical budget of subduction zones. Yet, the mechanisms of sulphur and carbon cycling within subduction zones are still unclear, in part because data are typically derived from arc volcanoes where fluid compositions are modified during transport through the mantle wedge. We determined the bulk rock elemental, and sulphur and carbon isotope compositions of exhumed ultramafic and metabasic rocks from Syros, Greece. Comparison of isotopic data with major and trace element compositions indicates seawater alteration and chemical exchange with sediment-derived fluids within the subduction zone channel. We show that small bodies of detached slab material are subject to metasomatic processes during exhumation, in contrast to large sequences of obducted ophiolitic sections that retain their seafloor alteration signatures. In particular, fluids circulating along the plate interface can cause sulphur mobilization during several stages of exhumation within high-pressure rocks. This takes place more pervasively in serpentinites compared to mafic rocks.
    Description: This project was supported by NSF-EAR grant 1324566 to E.M.S. and B.C.G., and NSF EAR award 1250470 to M.J.C. We acknowledge support by the German Research Foundation and the Open Access Publication Fund of the Freie Universität Berlin.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 3077, doi:10.1038/s41467-018-05574-x.
    Description: Paleoclimate reconstructions are only as good as their chronology. In particular, different chronological assumptions for marine sediment cores can lead to different reconstructions of ocean ventilation age and atmosphere−ocean carbon exchange history. Here we build the first high-resolution chronology that is free of the dating uncertainties common in marine sediment records, based on radiocarbon dating twigs found with computed tomography scans in two cores from the Eastern Equatorial Pacific (EEP). With this accurate chronology, we show that the ventilation ages of the EEP thermocline and intermediate waters were similar to today during the Last Glacial Maximum and deglaciation, in contradiction with previous studies. Our results suggest that the glacial respired carbon pool in the EEP was not significantly older than today, and that the deglacial strengthening of the equatorial Pacific carbon source was probably driven by low-latitude processes rather than an increased subsurface supply of upwelled carbon from high-latitude oceans.
    Description: The lab work at NOSAMS was supported by Ocean Ventures Fund from WHOI and an NOSAMS graduate internship granted to N.Z
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  • 39
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 15219, doi:10.1038/s41598-018-33283-4.
    Description: This Article corrects an error in Equation 1
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  • 40
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 15740, doi:10.1038/s41598-018-33640-3.
    Description: Hurricanes passing over the ocean can mix the water column down to great depths and resuspend massive volumes of sediments on the continental shelves. Consequently, organic carbon and reduced inorganic compounds associated with these sediments can be resuspended from anaerobic portions of the seabed and re-exposed to dissolved oxygen (DO) in the water column. This process can drive DO consumption as sediments become oxidized. Previous studies have investigated the effect of hurricanes on DO in different coastal regions of the world, highlighting the alleviation of hypoxic conditions by extreme winds, which drive vertical mixing and re-aeration of the water column. However, the effect of hurricane-induced resuspended sediments on DO has been neglected. Here, using a diverse suite of datasets for the northern Gulf of Mexico, we find that in the few days after a hurricane passage, decomposition of resuspended shelf sediments consumes up to a fifth of the DO added to the bottom of the water column during vertical mixing. Despite uncertainty in this value, we highlight the potential significance of this mechanism for DO dynamics. Overall, sediment resuspension likely occurs over all continental shelves affected by tropical cyclones, potentially impacting global cycles of marine DO and carbon.
    Description: Support for J. Moriarty was provided by the USGS Mendenhall Program.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2864, doi:10.1038/s41467-018-05313-2.
    Description: The mechanisms of transfer of crustal material from the subducting slab to the overlying mantle wedge are still debated. Mélange rocks, formed by mixing of sediments, oceanic crust, and ultramafics along the slab-mantle interface, are predicted to ascend as diapirs from the slab-top and transfer their compositional signatures to the source region of arc magmas. However, the compositions of melts that result from the interaction of mélanges with a peridotite wedge remain unknown. Here we present experimental evidence that melting of peridotite hybridized by mélanges produces melts that carry the major and trace element abundances observed in natural arc magmas. We propose that differences in nature and relative contributions of mélanges hybridizing the mantle produce a range of primary arc magmas, from tholeiitic to calc-alkaline. Thus, assimilation of mélanges into the wedge may play a key role in transferring subduction signatures from the slab to the source of arc magmas.
    Description: This project was supported by the WHOI Ocean Exploration Institute (OEI) 27071178 to V.L.R.; Previous related projects were supported by NSF EAR-1348063 and WHOI OEI to H.R.M.
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Cell Death and Disease 9 (2018): 663, doi:10.1038/s41419-018-0704-9.
    Description: The poor regenerative capacity of descending neurons is one of the main causes of the lack of recovery after spinal cord injury (SCI). Thus, it is of crucial importance to find ways to promote axonal regeneration. In addition, the prevention of retrograde degeneration leading to the atrophy/death of descending neurons is an obvious prerequisite to activate axonal regeneration. Lampreys show an amazing regenerative capacity after SCI. Recent histological work in lampreys suggested that GABA, which is massively released after a SCI, could promote the survival of descending neurons. Here, we aimed to study if GABA, acting through GABAB receptors, promotes the survival and axonal regeneration of descending neurons of larval sea lampreys after a complete SCI. First, we used in situ hybridization to confirm that identifiable descending neurons of late-stage larvae express the gabab1 subunit of the GABAB receptor. We also observed an acute increase in the expression of this subunit in descending neurons after SCI, which further supported the possible role of GABA and GABAB receptors in promoting the survival and regeneration of these neurons. So, we performed gain and loss of function experiments to confirm this hypothesis. Treatments with GABA and baclofen (GABAB agonist) significantly reduced caspase activation in descending neurons 2 weeks after a complete SCI. Long-term treatments with GABOB (a GABA analogue) and baclofen significantly promoted axonal regeneration of descending neurons after SCI. These data indicate that GABAergic signalling through GABAB receptors promotes the survival and regeneration of descending neurons after SCI. Finally, we used morpholinos against the gabab1 subunit to knockdown the expression of the GABAB receptor in descending neurons. Long-term morpholino treatments caused a significant inhibition of axonal regeneration. This shows that endogenous GABA promotes axonal regeneration after a complete SCI in lampreys by activating GABAB receptors.
    Description: Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund 2007–2013 (Grant number: BFU2014-56300-P) and Xunta de Galicia (Grant number: GPC2014/030). D.R.-S. was supported by a fellowship from EMBO (Ref.: 7010) to carry out a short-term stay at the laboratory of JRM. A.B.-I. was supported by a grant from the Xunta de Galicia (Grant number: 2016-PG008) and a grant from the crowdfunding platform Precipita (FECYT; Spanish Ministry of Economy and Competitiveness; grant number 2017-CP081).
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  • 43
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 2431, doi:10.1038/s41467-018-04421-3.
    Description: Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS.
    Description: This research was supported by the NSF Antarctic program through Award #1341630.
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  • 44
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 11997, doi:10.1038/s41598-018-30091-8.
    Description: The abundance of organic carbon (OC) in vegetation and soils (~2,600 PgC) compared to carbon in the atmosphere (~830 PgC) highlights the importance of terrestrial OC in global carbon budgets. The residence time of OC in continental reservoirs, which sets the rates of carbon exchange between land and atmosphere, represents a key uncertainty in global carbon cycle dynamics. Retention of terrestrial OC can also distort bulk OC- and biomarker-based paleorecords, yet continental storage timescales remain poorly quantified. Using “bomb” radiocarbon (14C) from thermonuclear weapons testing as a tracer, we model leaf-wax fatty acid and bulk OC 14C signatures in a river-proximal marine sediment core from the Bay of Bengal in order to constrain OC storage timescales within the Ganges-Brahmaputra (G-B) watershed. Our model shows that 79–83% of the leaf-waxes in this core were stored in continental reservoirs for an average of 1,000–1,200 calendar years, while the remainder was stored for an average of 15 years. This age structure distorts high-resolution organic paleorecords across geologically rapid events, highlighting that compound-specific proxy approaches must consider storage timescales. Furthermore, these results show that future environmental change could destabilize large stores of old - yet reactive - OC currently stored in tropical basins.
    Description: We acknowledge funding support from the Agouron Institute Postdoctoral Fellowship (K.L.F), the US National Science Foundation (Awards: OCE-1333387 and OCE-13333826), the Investment in Science Fund given primarily by WHOI Trustee and Corporation Members, and the Swiss National Science Foundation (Award: 200020_163162).
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  • 45
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 13478, doi:10.1038/s41598-018-31175-1.
    Description: Agricultural intensification offers potential to grow more food while reducing the conversion of native ecosystems to croplands. However, intensification also risks environmental degradation through emissions of the greenhouse gas nitrous oxide (N2O) and nitrate leaching to ground and surface waters. Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N2O emissions, and N leaching in an Amazon soybean-maize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil. Application of N fertilizer above 80 kg N ha−1 yr−1 increased maize yield and N2O emissions only slightly. Unlike experiences in temperate regions, leached nitrate accumulated in deep soils with increased fertilizer and conversion to cropping at N fertilization rates 〉80 kg N ha−1, which exceeded maize demand. This raises new questions about the capacity of tropical agricultural soils to store nitrogen, which may determine when and how much nitrogen impacts surface waters.
    Description: This project was supported by grants from NSF (DEB-1257944, DEB-1257391, DEB1457017, EF-1541770, EF-1655432, EF-1519342, IOS-1660034, IOS-1457662, and EAR-1739724) to M. Macedo, C. Neill, and M.T. Coe.
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  • 46
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 10140, doi:10.1038/s41598-018-28455-1.
    Description: Haynesina germanica, an ubiquitous benthic foraminifer in intertidal mudflats, has the remarkable ability to isolate, sequester, and use chloroplasts from microalgae. The photosynthetic functionality of these kleptoplasts has been demonstrated by measuring photosystem II quantum efficiency and O2 production rates, but the precise role of the kleptoplasts in foraminiferal metabolism is poorly understood. Thus, the mechanism and dynamics of C and N assimilation and translocation from the kleptoplasts to the foraminiferal host requires study. The objective of this study was to investigate, using correlated TEM and NanoSIMS imaging, the assimilation of inorganic C and N (here ammonium, NH4+) in individuals of a kleptoplastic benthic foraminiferal species. H. germanica specimens were incubated for 20 h in artificial seawater enriched with H13CO3− and 15NH4+ during a light/dark cycle. All specimens (n = 12) incorporated 13C into their endoplasm stored primarily in the form of lipid droplets. A control incubation in darkness resulted in no 13C-uptake, strongly suggesting that photosynthesis is the process dominating inorganic C assimilation. Ammonium assimilation was observed both with and without light, with diffuse 15N-enrichment throughout the cytoplasm and distinct 15N-hotspots in fibrillar vesicles, electron-opaque bodies, tubulin paracrystals, bacterial associates, and, rarely and at moderate levels, in kleptoplasts. The latter observation might indicate that the kleptoplasts are involved in N assimilation. However, the higher N assimilation observed in the foraminiferal endoplasm incubated without light suggests that another cytoplasmic pathway is dominant, at least in darkness. This study clearly shows the advantage provided by the kleptoplasts as an additional source of carbon and provides observations of ammonium uptake by the foraminiferal cell.
    Description: This work was supported by the Swiss National Science Foundation (grant no. 200021_149333) and was part of the CNRS EC2CO-Lefe project ForChlo. It was also supported by the Region Pays de la Loire (Post-doc position of TJ, on FRESCO project) as well as the WHOI Robert W. Morse Chair for Excellence in Oceanography and The Investment in Science Fund at WHOI.
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  • 47
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 13556, doi:10.1038/s41598-018-31710-0.
    Description: In mammals, a complex array of oral sensors assess the taste, temperature and haptic properties of food. Although the representation of taste has been extensively studied in the gustatory cortex, it is unclear how the somatosensory cortex encodes information about the properties of oral stimuli. Moreover, it is poorly understood how different oral sensory modalities are integrated and how sensory responses are translated into oral motor actions. To investigate whether oral somatosensory cortex processes food-related sensations and movements, we performed in vivo whole-cell recordings and motor mapping experiments in rats. Neurons in oral somatosensory cortex showed robust post-synaptic and sparse action potential responses to air puffs. Membrane potential showed that cold water evoked larger responses than room temperature or hot water. Most neurons showed no clear tuning of responses to bitter, sweet and neutral gustatory stimuli. Finally, motor mapping experiments with histological verification revealed an initiation of movements related to food consumption behavior, such as jaw opening and tongue protrusions. We conclude that somatosensory cortex: (i) provides a representation of the temperature of oral stimuli, (ii) does not systematically encode taste information and (iii) influences orofacial movements related to food consummatory behavior.
    Description: This work was supported by the Marine Biological Laboratory, Humboldt Universität zu Berlin and Neurocure.
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  • 48
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 3500, doi:10.1038/s41467-018-05804-2.
    Description: Subduction zone magmas are more oxidised on eruption than those at mid-ocean ridges. This is attributed either to oxidising components, derived from subducted lithosphere (slab) and added to the mantle wedge, or to oxidation processes occurring during magma ascent via differentiation. Here we provide direct evidence for contributions of oxidising slab agents to melts trapped in the sub-arc mantle. Measurements of sulfur (S) valence state in sub-arc mantle peridotites identify sulfate, both as crystalline anhydrite (CaSO4) and dissolved SO42− in spinel-hosted glass (formerly melt) inclusions. Copper-rich sulfide precipitates in the inclusions and increased Fe3+/∑Fe in spinel record a S6+–Fe2+ redox coupling during melt percolation through the sub-arc mantle. Sulfate-rich glass inclusions exhibit high U/Th, Pb/Ce, Sr/Nd and δ34S (+ 7 to + 11‰), indicating the involvement of dehydration products of serpentinised slab rocks in their parental melt sources. These observations provide a link between liberated slab components and oxidised arc magmas.
    Description: We acknowledge financial support by the Australian Research Council (DE120100513 and DP120104240) and the ESRF for beam time (EC1061 and ES238).
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  • 49
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 9478, doi:10.1038/s41598-018-26948-7.
    Description: Tidal wetlands produce long-term soil organic carbon (C) stocks. Thus for carbon accounting purposes, we need accurate and precise information on the magnitude and spatial distribution of those stocks. We assembled and analyzed an unprecedented soil core dataset, and tested three strategies for mapping carbon stocks: applying the average value from the synthesis to mapped tidal wetlands, applying models fit using empirical data and applied using soil, vegetation and salinity maps, and relying on independently generated soil carbon maps. Soil carbon stocks were far lower on average and varied less spatially and with depth than stocks calculated from available soils maps. Further, variation in carbon density was not well-predicted based on climate, salinity, vegetation, or soil classes. Instead, the assembled dataset showed that carbon density across the conterminous united states (CONUS) was normally distributed, with a predictable range of observations. We identified the simplest strategy, applying mean carbon density (27.0 kg C m−3), as the best performing strategy, and conservatively estimated that the top meter of CONUS tidal wetland soil contains 0.72 petagrams C. This strategy could provide standardization in CONUS tidal carbon accounting until such a time as modeling and mapping advancements can quantitatively improve accuracy and precision.
    Description: Synthesis efforts were funded by NASA Carbon Monitoring System (CMS; NNH14AY67I), USGS LandCarbon and the Smithsonian Institution. J.R.H. was additionally supported by the NSF-funded Coastal Carbon Research Coordination Network while completing this manuscript (DEB-1655622). J.M.S. coring efforts were funded by NSF (EAR-1204079). B.P.H. coring efforts were funded by Earth Observatory (Publication Number 197).
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  • 50
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Communications Biology 1 (2018): 177, doi:10.1038/s42003-018-0183-7.
    Description: The oceans are warming and coral reefs are bleaching with increased frequency and severity, fueling concerns for their survival through this century. Yet in the central equatorial Pacific, some of the world’s most productive reefs regularly experience extreme heat associated with El Niño. Here we use skeletal signatures preserved in long-lived corals on Jarvis Island to evaluate the coral community response to multiple successive heatwaves since 1960. By tracking skeletal stress band formation through the 2015-16 El Nino, which killed 95% of Jarvis corals, we validate their utility as proxies of bleaching severity and show that 2015-16 was not the first catastrophic bleaching event on Jarvis. Since 1960, eight severe (〉30% bleaching) and two moderate (〈30% bleaching) events occurred, each coinciding with El Niño. While the frequency and severity of bleaching on Jarvis did not increase over this time period, 2015–16 was unprecedented in magnitude. The trajectory of recovery of this historically resilient ecosystem will provide critical insights into the potential for coral reef resilience in a warming world.
    Description: Funding for this study was provided by National Science Foundation awards OCE 1537338, OCE 1605365, and OCE 1031971 to A.L.C., and the Robertson Foundation to A.L.C., National Science Foundation Graduate Research Fellowships to T.M.D. and A.E.A., and a National Defense Science and Engineering Graduate Fellowship to H.E.R.
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  • 51
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 17437, doi:10.1038/s41598-018-35309-3.
    Description: During recent years, rapid seasonal growth of macroalgae covered extensive areas within the Yellow Sea, developing the world’s most spatially extensive “green tide”. The remarkably fast accumulation of macroalgal biomass is the joint result of high nitrogen supplies in Yellow Sea waters, plus ability of the macroalgae to optionally use C4 photosynthetic pathways that facilitate rapid growth. Stable isotopic evidence shows that the high nitrogen supply is derived from anthropogenic sources, conveyed from watersheds via river discharges, and by direct atmospheric deposition. Wastewater and manures supply about half the nitrogen used by the macroalgae, fertiliser and atmospheric deposition each furnish about a quarter of the nitrogen in macroalgae. The massive green tides affecting the Yellow Sea are likely to increase, with significant current and future environmental and human consequences. Addressing these changing trajectories will demand concerted investment in new basic and applied research as the basis for developing management policies.
    Description: This work was supported by the State Key Project of Research and Development Plan (2016YFC1402106).
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  • 52
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 5179, doi:10.1038/s41467-018-07346-z.
    Description: Sunlight is the dominant control on phytoplankton biosynthetic activity, and darkness deprives them of their primary external energy source. Changes in the biochemical composition of phytoplankton communities over diel light cycles and attendant consequences for carbon and energy flux in environments remain poorly elucidated. Here we use lipidomic data from the North Pacific subtropical gyre to show that biosynthesis of energy-rich triacylglycerols (TAGs) by eukaryotic nanophytoplankton during the day and their subsequent consumption at night drives a large and previously uncharacterized daily carbon cycle. Diel oscillations in TAG concentration comprise 23 ± 11% of primary production by eukaryotic nanophytoplankton representing a global flux of about 2.4 Pg C yr−1. Metatranscriptomic analyses of genes required for TAG biosynthesis indicate that haptophytes and dinoflagellates are active members in TAG production. Estimates suggest that these organisms could contain as much as 40% more calories at sunset than at sunrise due to TAG production.
    Description: This work was supported by a grant from the Simons Foundation, and is a contribution of the Simons Collaboration on Ocean Processes and Ecology (SCOPE award # 329108, B.A.S.V.M.). K.W.B. was further supported by the Postdoctoral Scholarship Program at Woods Hole Oceanographic Institution & U.S. Geological Survey.
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  • 53
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 4702, doi:10.1038/s41467-018-07076-2.
    Description: The orbital-scale timing of South Asian monsoon (SAM) precipitation is poorly understood. Here we present new SST and seawater δ18O (δ18Osw) records from the Bay of Bengal, the core convective region of the South Asian monsoon, over the past 1 million years. Our records reveal that SAM precipitation peaked in the precession band ~9 kyrs after Northern Hemisphere summer insolation maxima, in phase with records of SAM winds in the Arabian Sea and eastern Indian Ocean. Precession-band variance, however, accounts for ~30% of the total variance of SAM precipitation while it was either absent or dominant in records of the East Asian monsoon (EAM). This and the observation that SAM precipitation was phase locked with obliquity minima and was sensitive to Southern Hemisphere warming provides clear evidence that SAM and EAM precipitation responded differently to orbital forcing and highlights the importance of internal processes forcing monsoon variability.
    Description: This study was partly funded by the German Science Foundation, DFG, IODP Priority Program (grant HA 5751/3-1).
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  • 54
    Publication Date: 2019-10-24
    Description: Conduit geometry affects magma ascent dynamics and, consequently, the style and evolution of volcanic eruptions. However, despite geological evidences support the occurrence of conduit widening during most volcanic eruptions, the factors controlling conduit enlargement are still unclear, and the effects of syn-eruptive variations of conduit geometry have not been investigated in depth yet. Based on numerical modeling and the application of appropriate stability criteria, we found out a strong relationship between magma rheology and conduit stability, with significant effects on eruptive dynamics. Indeed, in order to be stable, conduits feeding dacitic/rhyolitic eruptions need larger diameters respect to their phonolitic/trachytic counterparts, resulting in the higher eruption rates commonly observed in dacitic/rhyolitic explosive events. Thus, in addition to magma source conditions and viscosity-dependent efficiency for outgassing, we suggest that typical eruption rates for different magma types are also controlled by conduit stability. Results are consistent with a compilation of volcanological data and selected case studies. As stability conditions are not uniform along the conduit, widening is expected to vary in depth, and three axisymmetric geometries with depth-dependent radii were investigated. They are able to produce major modifications in eruptive parameters, suggesting that eruptive dynamics is influenced by syn-eruptive changes in conduit geometry.
    Description: Published
    Description: 4125
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: Volcanology ; Magma Ascent ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 55
    Publication Date: 2022-08-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 4494, doi:10.1038/s41598-018-22758-z.
    Description: Six velocity sections straddling Cape Hatteras show a deep counterflow rounding the Cape wedged beneath the poleward flowing Gulf Stream and the continental slope. This counterflow is likely the upper part of the equatorward-flowing Deep Western Boundary Current (DWBC). Hydrographic data suggest that the equatorward flow sampled by the shipboard 38 kHz ADCP comprises the Upper Labrador Sea Water (ULSW) layer and top of the Classical Labrador Sea Water (CLSW) layer. Continuous DWBC flow around the Cape implied by the closely-spaced velocity sections here is also corroborated by the trajectory of an Argo float. These findings contrast with previous studies based on floats and tracers in which the lightest DWBC constituents did not follow the boundary to cross under the Gulf Stream at Cape Hatteras but were diverted into the interior as the DWBC encountered the Gulf Stream in the crossover region. Additionally, our six quasi-synoptic velocity sections confirm that the Gulf Stream intensified markedly at that time as it approached the separation point and flowed into deeper waters. Downstream increases were observed not only in the poleward transport across the sections but also in the current’s maximum speed.
    Description: This research was supported by NSF through OCE-1558521 and OCE-1332667 and by a grant from North Carolina to the Renewable Ocean Energy Program.
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  • 56
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 660, doi:10.1038/s41467-018-02984-9.
    Description: Efforts to estimate the physical and economic impacts of future climate change face substantial challenges. To enrich the currently popular approaches to impact analysis—which involve evaluation of a damage function or multi-model comparisons based on a limited number of standardized scenarios—we propose integrating a geospatially resolved physical representation of impacts into a coupled human-Earth system modeling framework. Large internationally coordinated exercises cannot easily respond to new policy targets and the implementation of standard scenarios across models, institutions and research communities can yield inconsistent estimates. Here, we argue for a shift toward the use of a self-consistent integrated modeling framework to assess climate impacts, and discuss ways the integrated assessment modeling community can move in this direction. We then demonstrate the capabilities of such a modeling framework by conducting a multi-sectoral assessment of climate impacts under a range of consistent and integrated economic and climate scenarios that are responsive to new policies and business expectations.
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  • 57
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 3926, doi:10.1038/s41598-018-22313-w.
    Description: Despite concerted international effort to track and interpret shifts in the abundance and distribution of Adélie penguins, large populations continue to be identified. Here we report on a major hotspot of Adélie penguin abundance identified in the Danger Islands off the northern tip of the Antarctic Peninsula (AP). We present the first complete census of Pygoscelis spp. penguins in the Danger Islands, estimated from a multi-modal survey consisting of direct ground counts and computer-automated counts of unmanned aerial vehicle (UAV) imagery. Our survey reveals that the Danger Islands host 751,527 pairs of Adélie penguins, more than the rest of AP region combined, and include the third and fourth largest Adélie penguin colonies in the world. Our results validate the use of Landsat medium-resolution satellite imagery for the detection of new or unknown penguin colonies and highlight the utility of combining satellite imagery with ground and UAV surveys. The Danger Islands appear to have avoided recent declines documented on the Western AP and, because they are large and likely to remain an important hotspot for avian abundance under projected climate change, deserve special consideration in the negotiation and design of Marine Protected Areas in the region.
    Description: We gratefully acknowledge the financial support of the Dalio Foundation, Inc. through the Dalio Explore Fund, which provided all the financing for the Danger Island Expedition. We would like to thank additional support for analysis from the National Science Foundation (NSF PLR&GSS 1255058 - H.J.L. and P.M.; NSF PLR 1443585 – M.J.P.) and the National Aeronautical and Space Administration (NNX14AC32G; H.J.L. and M.S.). Geospatial support for the analysis of high resolution satellite imagery provided by the Polar Geospatial Center under NSF PLR awards 1043681 & 1559691.
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  • 58
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 7 (2017): 115, doi:10.1038/s41598-017-00091-1.
    Description: Mutations in Fused in Sarcoma/Translocated in Liposarcoma (FUS) cause familial forms of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by progressive axonal degeneration mainly affecting motor neurons. Evidence from transgenic mouse models suggests mutant forms of FUS exert an unknown gain-of-toxic function in motor neurons, but mechanisms underlying this effect remain unknown. Towards this end, we studied the effect of wild type FUS (FUS WT) and three ALS-linked variants (G230C, R521G and R495X) on fast axonal transport (FAT), a cellular process critical for appropriate maintenance of axonal connectivity. All ALS-FUS variants impaired anterograde and retrograde FAT in squid axoplasm, whereas FUS WT had no effect. Misfolding of mutant FUS is implicated in this process, as the molecular chaperone Hsp110 mitigated these toxic effects. Interestingly, mutant FUS-induced impairment of FAT in squid axoplasm and of axonal outgrowth in mammalian primary motor neurons involved aberrant activation of the p38 MAPK pathway, as also reported for ALS-linked forms of Cu, Zn superoxide dismutase (SOD1). Accordingly, increased levels of active p38 MAPK were detected in post-mortem human ALS-FUS brain tissues. These data provide evidence for a novel gain-of-toxic function for ALS-linked FUS involving p38 MAPK activation.
    Description: We are grateful for funding from NIH/NINDS (R01 NS078145, R01 NS090352, and R21 NS091860 to D.A.B., R01 NS066942A and R21 NS096642 to G.M., R01NS023868 and R01NS041170 to S.T.B.), the ALS Therapy Alliance/CVS Pharmacy (to D.A.B. and G.M.) and the ALS Association (to C.F. and J.M.).
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  • 59
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 1124, doi:10.1038/s41467-018-03134-x.
    Description: The ocean’s role in global climate change largely depends on its heat transport. Therefore, understanding the oceanic meridional heat transport (MHT) variability is a fundamental issue. Prevailing observational and modeling evidence suggests that MHT variability is primarily determined by the large-scale ocean circulation. Here, using new in situ observations in the eastern subpolar North Atlantic Ocean and an eddy-resolving numerical model, we show that energetic mesoscale eddies with horizontal scales of about 10–100 km profoundly modulate MHT variability on time scales from intra-seasonal to interannual. Our results reveal that the velocity changes due to mesoscale processes produce substantial variability for the MHT regionally (within sub-basins) and the subpolar North Atlantic as a whole. The findings have important implications for understanding the mechanisms for poleward heat transport variability in the subpolar North Atlantic Ocean, a key region for heat and carbon sequestration, ice–ocean interaction, and biological productivity.
    Description: J.Z. was financially supported by the Postdoctoral Scholar Program at WHOI, with funding provided by the Ocean and Climate Change Institute. This work was also supported by the US National Science Foundation (OCE-1258823 and OCE-1634886), as well as by China’s national key research and development projects (2016YFA0601803), the National Natural Science Foundation of China (41521091 and U1606402), the Qingdao National Laboratory for Marine Science and Technology (2015ASKJ01), and the Fundamental Research Funds for the Central Universities (201424001 and 201362048).
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  • 60
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 742, doi:10.1038/s41598-017-18757-1.
    Description: In mammals, spinal cord injury (SCI) leads to dramatic losses in neurons and synaptic connections, and consequently function. Unlike mammals, lampreys are vertebrates that undergo spontaneous regeneration and achieve functional recovery after SCI. Therefore our goal was to determine the complete transcriptional responses that occur after SCI in lampreys and to identify deeply conserved pathways that promote regeneration. We performed RNA-Seq on lamprey spinal cord and brain throughout the course of functional recovery. We describe complex transcriptional responses in the injured spinal cord, and somewhat surprisingly, also in the brain. Transcriptional responses to SCI in lampreys included transcription factor networks that promote peripheral nerve regeneration in mammals such as Atf3 and Jun. Furthermore, a number of highly conserved axon guidance, extracellular matrix, and proliferation genes were also differentially expressed after SCI in lampreys. Strikingly, ~3% of differentially expressed transcripts belonged to the Wnt pathways. These included members of the Wnt and Frizzled gene families, and genes involved in downstream signaling. Pharmacological inhibition of Wnt signaling inhibited functional recovery, confirming a critical role for this pathway. These data indicate that molecular signals present in mammals are also involved in regeneration in lampreys, supporting translational relevance of the model.
    Description: We gratefully acknowledge support from the National Institutes of Health (R03NS078519 to OB; R01GM104123 to JJS; R01NS078165 to JRM), The Feinstein Institute for Medical Research and The Marine Biological Laboratory, including the Charles Evans Foundation Research Award, the Albert and Ellen Grass Foundation Faculty Research Award, and The Eugene and Millicent Bell Fellowship Fund in Tissue Engineering.
    Keywords: Computational biology and bioinformatics ; Gene expression ; Spinal cord injury
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  • 61
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 266, doi:10.1038/s41467-017-02571-4.
    Description: Because microbial plankton in the ocean comprise diverse bacteria, algae, and protists that are subject to environmental forcing on multiple spatial and temporal scales, a fundamental open question is to what extent these organisms form ecologically cohesive communities. Here we show that although all taxa undergo large, near daily fluctuations in abundance, microbial plankton are organized into clearly defined communities whose turnover is rapid and sharp. We analyze a time series of 93 consecutive days of coastal plankton using a technique that allows inference of communities as modular units of interacting taxa by determining positive and negative correlations at different temporal frequencies. This approach shows both coordinated population expansions that demarcate community boundaries and high frequency of positive and negative associations among populations within communities. Our analysis thus highlights that the environmental variability of the coastal ocean is mirrored in sharp transitions of defined but ephemeral communities of organisms.
    Description: This work was supported by grants from the U.S. National Science Foundation (OCE-1441943) to M.F.P. and the U.S. Department of Energy (DE-SC0008743) to M.F.P. and E.J.A. A.M.M.-P. was partially supported by the Ramon Areces foundation through a postdoctoral fellowship. D.J.M. was supported by the U.S. National Science Foundation (OCE-1314642) and National Institute of Environmental Health Sciences (1P01ES021923-01) through the Woods Hole Center for Oceans and Human Health.
    Keywords: Marine biology ; Microbial ecology
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  • 62
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 121, doi:10.1038/s41467-017-02504-1.
    Description: Sediments in deep ocean trenches may contain crucial information on past earthquake history and constitute important sites of carbon burial. Here we present 14C data on bulk organic carbon (OC) and its thermal decomposition fractions produced by ramped pyrolysis/oxidation for a core retrieved from the 〉7.5 km-deep Japan Trench. High-resolution 14C measurements, coupled with distinctive thermogram characteristics of OC, reveal hemipelagic sedimentation interrupted by episodic deposition of pre-aged OC in the trench. Low δ13C values and diverse 14C ages of thermal fractions imply that the latter material originates from the adjacent margin, and the co-occurrence of pre-aged OC with intervals corresponding to known earthquake events implies tectonically triggered, gravity-flow-driven supply. We show that 14C ages of thermal fractions can yield valuable chronological constraints on sedimentary sequences. Our findings shed new light on links between tectonically driven sedimentological processes and marine carbon cycling, with implications for carbon dynamics in hadal environments.
    Description: This study is supported by Doc.Mobility Fellowship (P1EZP2_159064) (R.B.) from the Swiss National Science Foundation (SNSF). This work is also supported by SNF “CAPS-LOCK” project 200021_140850 (T.I.E.), by SNSF grant (133481) (M.S.), and Austrian Science Foundation (P 29678-N28) (M.S.).
    Keywords: Carbon cycle ; Sedimentology
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  • 63
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 4547, doi:10.1038/s41598-018-22732-9.
    Description: The assembly of membranous extensions such as microvilli and cilia in polarized cells is a tightly regulated, yet poorly understood, process. Peptidylglycine α-amidating monooxygenase (PAM), a membrane enzyme essential for the synthesis of amidated bioactive peptides, was recently identified in motile and non-motile (primary) cilia and has an essential role in ciliogenesis in Chlamydomonas, Schmidtea and mouse. In mammalian cells, changes in PAM levels alter secretion and organization of the actin cytoskeleton. Here we show that lack of Pam in zebrafish recapitulates the lethal edematous phenotype observed in Pam−/− mice and reveals additional defects. The pam−/− zebrafish embryos display an initial striking loss of microvilli and subsequently impaired ciliogenesis in the pronephros. In multiciliated mouse tracheal epithelial cells, vesicular PAM staining colocalizes with apical actin, below the microvilli. In PAM-deficient Chlamydomonas, the actin cytoskeleton is dramatically reorganized, and expression of an actin paralogue is upregulated. Biochemical assays reveal that the cytosolic PAM C-terminal domain interacts directly with filamentous actin but does not alter the rate of actin polymerization or disassembly. Our results point to a critical role for PAM in organizing the actin cytoskeleton during development, which could in turn impact both microvillus formation and ciliogenesis.
    Description: This study was supported by grants DK032949 (to BAE and REM), DK044464 (to JDG) and GM051293 (to SMK) from the National Institutes of Health.
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  • 64
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 12 (2018): 1-16, doi:10.1038/ismej.2017.187.
    Description: The rock-hosted subseafloor crustal aquifer harbors a reservoir of microbial life that may influence global marine biogeochemical cycles. Here we utilized metagenomic libraries of crustal fluid samples from North Pond, located on the flanks of the Mid-Atlantic Ridge, a site with cold, oxic subseafloor fluid circulation within the upper basement to query microbial diversity. Twenty-one samples were collected during a 2-year period to examine potential microbial metabolism and community dynamics. We observed minor changes in the geochemical signatures over the 2 years, yet the microbial community present in the crustal fluids underwent large shifts in the dominant taxonomic groups. An analysis of 195 metagenome-assembled genomes (MAGs) were generated from the data set and revealed a connection between litho- and autotrophic processes, linking carbon fixation to the oxidation of sulfide, sulfur, thiosulfate, hydrogen, and ferrous iron in members of the Proteobacteria, specifically the Alpha-, Gamma- and Zetaproteobacteria, the Epsilonbacteraeota and the Planctomycetes. Despite oxic conditions, analysis of the MAGs indicated that members of the microbial community were poised to exploit hypoxic or anoxic conditions through the use of microaerobic cytochromes, such as cbb3- and bd-type cytochromes, and alternative electron acceptors, like nitrate and sulfate. Temporal and spatial trends from the MAGs revealed a high degree of functional redundancy that did not correlate with the shifting microbial community membership, suggesting functional stability in mediating subseafloor biogeochemical cycles. Collectively, the repeated sampling at multiple sites, together with the successful binning of hundreds of genomes, provides an unprecedented data set for investigation of microbial communities in the cold, oxic crustal aquifer.
    Description: This work was supported by NSF OCE1062006 to JAH and NSF OCE1061827 to BTG. The Gordon and Betty Moore Foundation sponsored most of the observatory components at North Pond through grant GBMF1609. The Center for Dark Energy Biosphere Investigations (C-DEBI) (OCE-0939564), a National Science Foundation-funded Science and Technology Centers of Excellence also supported the participation of CGW, JAH and BJT.
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  • 65
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 209, doi:10.1038/s41467-017-02105-y.
    Description: Correction to: Nature Communications 8:172 https://doi.org/10.1038/s41467-017-00197-0; Article published online: 2 August 2017
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  • 66
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 305, doi:10.1038/s41467-017-02701-y.
    Description: Correction to: Nature Communications https://doi.org/10.1038/s41467-017-01229-5, Article published online 07 November 2017
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  • 67
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 12 (2018): 237–252, doi:10.1038/ismej.2017.165.
    Description: Temperate coastal marine environments are replete with complex biotic and abiotic interactions that are amplified during spring and summer phytoplankton blooms. During these events, heterotrophic bacterioplankton respond to successional releases of dissolved organic matter as algal cells are lysed. Annual seasonal shifts in the community composition of free-living bacterioplankton follow broadly predictable patterns, but whether similar communities respond each year to bloom disturbance events remains unknown owing to a lack of data sets, employing high-frequency sampling over multiple years. We capture the fine-scale microdiversity of these events with weekly sampling using a high-resolution method to discriminate 16S ribosomal RNA gene amplicons that are 〉99% identical. Furthermore, we used 2 complete years of data to facilitate identification of recurrent sub-networks of co-varying microbes. We demonstrate that despite inter-annual variation in phytoplankton blooms and despite the dynamism of a coastal–oceanic transition zone, patterns of microdiversity are recurrent during both bloom and non-bloom conditions. Sub-networks of co-occurring microbes identified reveal that correlation structures between community members appear quite stable in a seasonally driven response to oligotrophic and eutrophic conditions.
    Description: PLB is supported by the European Research Council Advanced Investigator grant ABYSS 294757 to Antje Boetius. AF-G is supported by the European Union’s Horizon 2020 research and innovation program (Blue Growth: Unlocking the potential of Seas and Oceans) under grant agreement no. (634486) (project acronym INMARE). This study was funded by the Max Planck Society. Further support by the Department of Energy Joint Genome Institute (CSP COGITO) and DFG (FOR2406) is acknowledged by HT (TE 813/2-1) and RA (Am 73/9-1).
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  • 68
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    In: PLoS ONE
    Publication Date: 2018-12-14
    Description: by Cedric Alaux, Samuel Soubeyrand, Alberto Prado, Mathilde Peruzzi, Alban Maisonnasse, Julien Vallon, Julie Hernandez, Pascal Jourdan, Yves Le Conte Honeybee colonies are increasingly exposed to environmental stress factors, which can lead to their decline or failure. However, there are major gaps in stressor risk assessment due to the difficulty of assessing the honeybee colony state and detecting abnormal events. Since stress factors usually induce a demographic disturbance in the colony (e.g. loss of foragers, early transition from nurse to forager state), we suggest that disturbances could be revealed indirectly by measuring the age- and task-related physiological state of bees, which can be referred to as biological age (an indicator of the changes in physiological state that occur throughout an individual lifespan). We therefore estimated the biological age of bees from the relationship between age and biomarkers of task specialization (vitellogenin and the adipokinetic hormone receptor). This relationship was determined from a calibrated sample set of known-age bees and mathematically modelled for biological age prediction. Then, we determined throughout the foraging season the evolution of the biological age of bees from colonies with low (conventional apiary) or high Varroa destructor infestation rates (organic apiary). We found that the biological age of bees from the conventional apiary progressively decreased from the spring (17 days) to the fall (6 days). However, in colonies from the organic apiary, the population aged from spring (13 days) to summer (18.5 days) and then rejuvenated in the fall (13 days) after Varroa treatment. Biological age was positively correlated with the amount of brood (open and closed cells) in the apiary with low Varroa pressure, and negatively correlated with Varroa infestation level in the apiary with high Varroa pressure. Altogether, these results show that the estimation of biological age is a useful and effective method for assessing colony demographic state and likely detrimental effects of stress factors.
    Electronic ISSN: 1932-6203
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  • 69
    Publication Date: 2018-12-14
    Description: by Maganizo B. Chagomerana, William C. Miller, Jennifer H. Tang, Irving F. Hoffman, Bryna J. Harrington, Bethany DiPrete, Shaphil Wallie, Allan Jumbe, Laura Limarzi, Mina C. Hosseinipour Background In Malawi’s PMTCT Option B+ program, HIV-infected pregnant women who are already receiving ART are continued on their current therapy regimen without testing for treatment failure at the first antenatal care (ANC) visit. HIV RNA screening at ANC may identify women with treatment failure and ensure that viral suppression is maintained throughout the pregnancy. Methods We conducted a cross-sectional study of HIV-infected pregnant women who had been receiving ART for at least 6 months at the first ANC visit under the PMTCT Option B+ program at Bwaila Hospital in Lilongwe, Malawi from June 2015 to December 2017. Poisson regression models with robust variance were used to investigate the predictors of ART treatment failure defined as viral load ≥1000 copies/ml. Results The median age of 864 women tested for ART failure was 31.1 years (interquartile range: 26.9–34.5). The prevalence of treatment failure was 7.6% (95% confidence interval (CI): 6.0–9.6). CD4 cell count (adjusted prevalence ratio (aPR) = 0.57; 95% CI: 0.50–0.65) was strongly associated with treatment failure. Conclusion The low prevalence of treatment failure among women presenting for their first ANC in urban Malawi demonstrates success of Option B+ in maintaining viral suppression and suggests progress towards the last 90% of the UNAIDS 90-90-90 targets. Women failing on ART should be identified early for adherence counseling and may require switching to an alternative ART regimen.
    Electronic ISSN: 1932-6203
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  • 70
    Publication Date: 2018-12-14
    Description: by Rie Matsushima-Nishiwaki, Noriko Yamada, Kouki Fukuchi, Osamu Kozawa A bioactive lipid, sphingosine 1-phosphate (S1P), acts extracellularly as a potent mediator, and is implicated in the progression of various cancers including hepatocellular carcinoma (HCC). S1P exerts its functions by binding to five types of specific receptors, S1P receptor 1 (S1PR1), S1PR2, S1PR3, S1PR4 and S1PR5 on the plasma membrane. However, the exact roles of S1P and each S1PR in HCC cells remain to be clarified. In the present study, we investigated the effect of S1P on the hepatocyte growth factor (HGF)-induced migration of human HCC-derived HuH7 cells, and the involvement of each S1PR. S1P dose-dependently reduced the HGF-induced migration of HuH7 cells. We found that all S1PRs exist in the HuH7 cells. Among each selective agonist for five S1PRs, CYM5520, a selective S1PR2 agonist, significantly suppressed the HGF-induced HuH7 cell migration whereas selective agonists for S1PR1, S1PR3, S1PR4 or S1PR5 failed to affect the migration. The reduction of the HGF-induced migration by S1P was markedly reversed by treatment of JTE013, a selective antagonist for S1PR2, and S1PR2- siRNA. These results strongly suggest that S1P reduces the HGF-induced HCC cell migration via S1PR2. Our findings may provide a novel potential of S1PR2 to therapeutic strategy for metastasis of HCC.
    Electronic ISSN: 1932-6203
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  • 71
    Publication Date: 2018-12-14
    Description: by Mircea Zloteanu, Nigel Harvey, David Tuckett, Giacomo Livan The Sharing Economy (SE) is a growing ecosystem focusing on peer-to-peer enterprise. In the SE the information available to assist individuals (users) in making decisions focuses predominantly on community-generated trust and reputation information. However, how such information impacts user judgement is still being understood. To explore such effects, we constructed an artificial SE accommodation platform where we varied the elements related to hosts’ digital identity, measuring users’ perceptions and decisions to interact. Across three studies, we find that trust and reputation information increases not only the users’ perceived trustworthiness, credibility, and sociability of hosts, but also the propensity to rent a private room in their home. This effect is seen when providing users both with complete profiles and profiles with partial user-selected information. Closer investigations reveal that three elements relating to the host’s digital identity are sufficient to produce such positive perceptions and increased rental decisions, regardless of which three elements are presented. Our findings have relevant implications for human judgment and privacy in the SE, and question its current culture of ever increasing information-sharing.
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  • 72
    Publication Date: 2018-12-14
    Description: by Tucker Maxson, Candace D. Blancett, Amanda S. Graham, Christopher P. Stefan, Timothy D. Minogue Development and implementation of rapid antimicrobial susceptibility testing is critical for guiding patient care and improving clinical outcomes, especially in cases of sepsis. One approach to reduce the time-to-answer for antimicrobial susceptibility is monitoring the inhibition of DNA production, as differences in DNA concentrations are more quickly impacted compared to optical density changes in traditional antimicrobial susceptibility testing. Here, we use real-time PCR to rapidly determine antimicrobial susceptibility after short incubations with antibiotic. Application of this assay to a collection of 144 isolates in mock blood culture, covering medically relevant pathogens displaying high rates of resistance, provided susceptibility data in under 4 hours. This assay provided categorical agreement with a reference method in 96.3% of cases across all species. Sequencing of a subset of PCR amplicons showed accurate genus level identification. Overall, implementation of this method could provide accurate susceptibility results with a reduced time-to-answer for a number of medically relevant bacteria commonly isolated from blood culture.
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  • 73
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    In: PLoS ONE
    Publication Date: 2018-12-14
    Description: by Ágota Nagy, Levente Kovács, Zoltán Lipinszki, Margit Pál, Péter Deák In most Eukaryotes, ubiquitin either exists as free monoubiquitin or as a molecule that is covalently linked to other proteins. These two forms cycle between each other and due to the concerted antagonistic activity of ubiquitylating and deubiquitylating enzymes, an intracellular ubiquitin equilibrium is maintained that is essential for normal biological function. However, measuring the level and ratio of these forms of ubiquitin has been difficult and time consuming. In this paper, we have adapted a simple immunoblotting technique to monitor ubiquitin content and equilibrium dynamics in different developmental stages and tissues of Drosophila . Our data show that the level of total ubiquitin is distinct in different developmental stages, lowest at the larval-pupal transition and in three days old adult males, and highest in first instar larvae. Interestingly, the ratio of free mono-ubiquitin remains within 30–50% range of the total throughout larval development, but peaks to 70–80% at the larval-pupal and the pupal-adult transitions. It stays within the 70–80% range in adults. In developmentally and physiologically active tissues, the ratio of free ubiquitin is similarly high, most likely reflecting a high demand for ubiquitin availability. We also used this method to demonstrate the disruption of the finely tuned ubiquitin equilibrium by the abolition of proteasome function or the housekeeping deubiquitylase, Usp5. Our data support the notion that the ubiquitin equilibrium is regulated by tissue- and developmental stage-specific mechanisms.
    Electronic ISSN: 1932-6203
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  • 74
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    In: PLoS ONE
    Publication Date: 2018-12-14
    Description: by Huirong Cheng, Pei Hu, Weihua Wen, Ling Liu Three arsenic species in urine are measured using an atomic absorption spectrophotometer. RT-PCR is performed to detect the expression levels of AS3MT, 3 miRNAs, and 17 relative mRNAs in 43 workers producing arsenic trioxide, 36 workers who stopped exposure to arsenic for 85 days, and 24 individuals as the control group. The concentrations of urinary arsenic are very high in workers. A negative correlation between AS3MT and MiR-5 48c-3p is found. There exist significant changes for most selected miRNAs and mRNAs in workers. There are no significant differences between workers who stopped exposure to arsenic and the control group for most miRNAs and mRNAs, but the MiR-5 48c-3p levels show significant changes. Similar positive correlations between the expression of AS3MT and all selected mRNAs are found. Negative correlations between the expression of MiR-5 48c-3p and many relative mRNAs are found as well. AS3MT and MiR-5 48c-3p may regulate arsenic methylation jointly, which when involved in a group of relative mRNAs may play roles in arsenic metabolism and epigenetic changes caused by this metabolism.
    Electronic ISSN: 1932-6203
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  • 75
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    Publication Date: 2018-12-14
    Description: by Stefanie Hoehl, Gabriela Markova Infants’ cognitive development and learning rely profoundly on their interactions with other people. In the first year, infants become increasingly sensitive to others’ gaze and use it to focus their own attention on relevant visual input. However, infants are not passive observers in early social interactions, and these exchanges are characterized by high levels of contingency and reciprocity. Wass and colleagues offer first insights into the neurobehavioral dynamics of caregiver–infant interactions, demonstrating that caregivers’ scalp-recorded theta band activity responds to their infant’s changes in attention, and parental brain activation is associated with infants’ sustenance of attention. This research opens up entirely new ways of exploring caregiver–infant interactions and to understand early social attention as a reciprocal and dynamic process.
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  • 76
    Publication Date: 2018-12-14
    Description: by Xinyi Liu, Diane L. Lister, Zhijun Zhao, Cameron A. Petrie, Xiongsheng Zeng, Penelope J. Jones, Richard A. Staff, Anil K. Pokharia, Jennifer Bates, Ravindra N. Singh, Steven A. Weber, Giedre Motuzaite Matuzeviciute, Guanghui Dong, Haiming Li, Hongliang Lü, Hongen Jiang, Jianxin Wang, Jian Ma, Duo Tian, Guiyun Jin, Liping Zhou, Xiaohong Wu, Martin K. Jones
    Electronic ISSN: 1932-6203
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  • 77
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    Publication Date: 2018-12-14
    Description: by Itamar Daniel Landau, Haim Sompolinsky We present a simple model for coherent, spatially correlated chaos in a recurrent neural network. Networks of randomly connected neurons exhibit chaotic fluctuations and have been studied as a model for capturing the temporal variability of cortical activity. The dynamics generated by such networks, however, are spatially uncorrelated and do not generate coherent fluctuations, which are commonly observed across spatial scales of the neocortex. In our model we introduce a structured component of connectivity, in addition to random connections, which effectively embeds a feedforward structure via unidirectional coupling between a pair of orthogonal modes. Local fluctuations driven by the random connectivity are summed by an output mode and drive coherent activity along an input mode. The orthogonality between input and output mode preserves chaotic fluctuations by preventing feedback loops. In the regime of weak structured connectivity we apply a perturbative approach to solve the dynamic mean-field equations, showing that in this regime coherent fluctuations are driven passively by the chaos of local residual fluctuations. When we introduce a row balance constraint on the random connectivity, stronger structured connectivity puts the network in a distinct dynamical regime of self-tuned coherent chaos. In this regime the coherent component of the dynamics self-adjusts intermittently to yield periods of slow, highly coherent chaos. The dynamics display longer time-scales and switching-like activity. We show how in this regime the dynamics depend qualitatively on the particular realization of the connectivity matrix: a complex leading eigenvalue can yield coherent oscillatory chaos while a real leading eigenvalue can yield chaos with broken symmetry. The level of coherence grows with increasing strength of structured connectivity until the dynamics are almost entirely constrained to a single spatial mode. We examine the effects of network-size scaling and show that these results are not finite-size effects. Finally, we show that in the regime of weak structured connectivity, coherent chaos emerges also for a generalized structured connectivity with multiple input-output modes.
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  • 78
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    Publication Date: 2018-12-14
    Description: by Maria E. Sousa, Michael H. Farkas
    Print ISSN: 1553-7390
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  • 79
    Publication Date: 2018-12-14
    Description: by Jonas R. Kunst, Esther N. Phillibert It is well-established that experiences of discrimination influence immigrants’ acculturation. Yet, whereas a large body of research has demonstrated the role of discrimination by members of the dominant societal group, surprisingly little is known about how being discriminated by members of one’s own group relates to the way immigrants acculturate. With a sample of 162 African first- and second-generation immigrants living in Norway, the present research investigated the relationship between both types of discrimination, acculturation and psychological well-being. It did so, focusing on discrimination based on one’s skin tone, a type of discrimination Africans can experience from White as well as African individuals. Results showed that skin-tone discrimination by Whites was associated with a lower host culture orientation. By contrast, skin-tone discrimination by Africans was associated with a lower heritage culture orientation. Mediation analyses showed that the positive relationship of skin-tone discrimination by Whites and Africans with life satisfaction was mediated by a lower host and heritage culture orientation respectively. This indirect relationship did not reach significance with self-esteem as dependent variable. Participants’ actual skin tone was unrelated to experiences of skin-tone discrimination. We discuss our results in light of previous research and highlight potential limitations.
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  • 80
    Publication Date: 2018-12-14
    Description: by Christian Agebratt, Edvin Ström, Thobias Romu, Olof Dahlqvist-Leinhard, Magnus Borga, Per Leandersson, Fredrik H. Nystrom
    Electronic ISSN: 1932-6203
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  • 81
    Publication Date: 2018-12-14
    Description: by Heïdi Serra, Kyuha Choi, Xiaohui Zhao, Alexander R. Blackwell, Juhyun Kim, Ian R. Henderson During meiosis, chromosomes undergo DNA double-strand breaks (DSBs), which can be repaired using a homologous chromosome to produce crossovers. Meiotic recombination frequency is variable along chromosomes and tends to concentrate in narrow hotspots. We mapped crossover hotspots located in the Arabidopsis thaliana RAC1 and RPP13 disease resistance genes, using varying haplotypic combinations. We observed a negative non-linear relationship between interhomolog divergence and crossover frequency within the hotspots, consistent with polymorphism locally suppressing crossover repair of DSBs. The fancm , recq4a recq4b , figl1 and msh2 mutants, or lines with increased HEI10 dosage, are known to show increased crossovers throughout the genome. Surprisingly, RAC1 crossovers were either unchanged or decreased in these genetic backgrounds, showing that chromosome location and local chromatin environment are important for regulation of crossover activity. We employed deep sequencing of crossovers to examine recombination topology within RAC1 , in wild type, fancm , recq4a recq4b and fancm recq4a recq4b backgrounds. The RAC1 recombination landscape was broadly conserved in the anti-crossover mutants and showed a negative relationship with interhomolog divergence. However, crossovers at the RAC1 5'-end were relatively suppressed in recq4a recq4b backgrounds, further indicating that local context may influence recombination outcomes. Our results demonstrate the importance of interhomolog divergence in shaping recombination within plant disease resistance genes and crossover hotspots.
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  • 82
    Publication Date: 2018-12-14
    Description: by Enrico Lavezzo, Michele Berselli, Ilaria Frasson, Rosalba Perrone, Giorgio Palù, Alessandra R. Brazzale, Sara N. Richter, Stefano Toppo G-quadruplexes are non-canonical nucleic-acid structures that control transcription, replication, and recombination in organisms. G-quadruplexes are present in eukaryotes, prokaryotes, and viruses. In the latter, mounting evidence indicates their key biological activity. Since data on viruses are scattered, we here present a comprehensive analysis of potential quadruplex-forming sequences (PQS) in the genome of all known viruses that can infect humans. We show that occurrence and location of PQSs are features characteristic of each virus class and family. Our statistical analysis proves that their presence within the viral genome is orderly arranged, as indicated by the possibility to correctly assign up to two-thirds of viruses to their exact class based on the PQS classification. For each virus we provide: i) the list of all PQS present in the genome (positive and negative strands), ii) their position in the viral genome, iii) the degree of conservation among strains of each PQS in its genome context, iv) the statistical significance of PQS abundance. This information is accessible from a database to allow the easy navigation of the results: http://www.medcomp.medicina.unipd.it/main_site/doku.php?id=g4virus. The availability of these data will greatly expedite research on G-quadruplex in viruses, with the possibility to accelerate finding therapeutic opportunities to numerous and some fearsome human diseases.
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  • 83
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    Publication Date: 2018-12-14
    Description: by Motoyasu Honma, Yuri Masaoka, Shinichi Koyama, Takeshi Kuroda, Akinori Futamura, Azusa Shiromaru, Yasuo Terao, Kenjiro Ono, Mitsuru Kawamura Parkinson's disease (PD) is associated with various cognitive impairments. However, the nature of cognitive modification in patients with PD remains to be elucidated. In the present study, we examined whether patients with PD could correct and maintain subjective time duration and line length estimation. After training sessions, in which participants repeatedly memorized either a duration or a length, we compared a learning performance in 20 PD patients with 20 healthy controls. In the case of duration in the PD patients, the learned durations immediately returned to baseline of pre-training within a few minutes. However, the patients’ ability to learn length estimation remained unimpaired. In contrast, healthy controls were able to retain the learned duration and length estimations. Time compression in PD's internal clock may become entrained to their altered duration estimation even after learning of accurate time duration. These deficits may be associated with disrupting cognitive modification in PD.
    Electronic ISSN: 1932-6203
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  • 84
    Publication Date: 2018-03-13
    Description: by Anne Keitel, Joachim Gross, Christoph Kayser During online speech processing, our brain tracks the acoustic fluctuations in speech at different timescales. Previous research has focused on generic timescales (for example, delta or theta bands) that are assumed to map onto linguistic features such as prosody or syllables. However, given the high intersubject variability in speaking patterns, such a generic association between the timescales of brain activity and speech properties can be ambiguous. Here, we analyse speech tracking in source-localised magnetoencephalographic data by directly focusing on timescales extracted from statistical regularities in our speech material. This revealed widespread significant tracking at the timescales of phrases (0.6–1.3 Hz), words (1.8–3 Hz), syllables (2.8–4.8 Hz), and phonemes (8–12.4 Hz). Importantly, when examining its perceptual relevance, we found stronger tracking for correctly comprehended trials in the left premotor (PM) cortex at the phrasal scale as well as in left middle temporal cortex at the word scale. Control analyses using generic bands confirmed that these effects were specific to the speech regularities in our stimuli. Furthermore, we found that the phase at the phrasal timescale coupled to power at beta frequency (13–30 Hz) in motor areas. This cross-frequency coupling presumably reflects top-down temporal prediction in ongoing speech perception. Together, our results reveal specific functional and perceptually relevant roles of distinct tracking and cross-frequency processes along the auditory–motor pathway.
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  • 85
    Publication Date: 2018-03-13
    Description: by Hao Ge, Pingping Wu, Hong Qian, Sunney Xiaoliang Xie Within an isogenic population, even in the same extracellular environment, individual cells can exhibit various phenotypic states. The exact role of stochastic gene-state switching regulating the transition among these phenotypic states in a single cell is not fully understood, especially in the presence of positive feedback. Recent high-precision single-cell measurements showed that, at least in bacteria, switching in gene states is slow relative to the typical rates of active transcription and translation. Hence using the lac operon as an archetype, in such a region of operon-state switching, we present a fluctuating-rate model for this classical gene regulation module, incorporating the more realistic operon-state switching mechanism that was recently elucidated. We found that the positive feedback mechanism induces bistability (referred to as deterministic bistability), and that the parameter range for its occurrence is significantly broadened by stochastic operon-state switching. We further show that in the absence of positive feedback, operon-state switching must be extremely slow to trigger bistability by itself. However, in the presence of positive feedback, which stabilizes the induced state, the relatively slow operon-state switching kinetics within the physiological region are sufficient to stabilize the uninduced state, together generating a broadened parameter region of bistability (referred to as stochastic bistability). We illustrate the opposite phenotype-transition rate dependence upon the operon-state switching rates in the two types of bistability, with the aid of a recently proposed rate formula for fluctuating-rate models. The rate formula also predicts a maximal transition rate in the intermediate region of operon-state switching, which is validated by numerical simulations in our model. Overall, our findings suggest a biological function of transcriptional “variations” among genetically identical cells, for the emergence of bistability and transition between phenotypic states.
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  • 86
    Publication Date: 2018-03-13
    Description: by Gerry Q. Tonkin-Hill, Leily Trianty, Rintis Noviyanti, Hanh H. T. Nguyen, Boni F. Sebayang, Daniel A. Lampah, Jutta Marfurt, Simon A. Cobbold, Janavi S. Rambhatla, Malcolm J. McConville, Stephen J. Rogerson, Graham V. Brown, Karen P. Day, Ric N. Price, Nicholas M. Anstey, Anthony T. Papenfuss, Michael F. Duffy Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to—or is selected by—this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients. The transcriptomes of 19 parasite isolates associated with severe malaria indicated that these parasites had decreased glycolysis without activation of compensatory pathways; altered chromatin structure and probably transcriptional regulation through decreased histone methylation; reduced surface expression of PfEMP1; and down-regulated expression of multiple chaperone proteins. Our RNAseq also identified novel associations between disease severity and PfEMP1 transcripts, domains, and smaller sequence segments and also confirmed all previously reported associations between expressed PfEMP1 sequences and severe disease. These findings will inform efforts to identify vaccine targets for severe malaria and also indicate how parasites adapt to—or are selected by—the host environment in severe malaria.
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  • 87
    Publication Date: 2018-03-13
    Description: by Michael Pablo, Samuel A. Ramirez, Timothy C. Elston Polarity establishment, the spontaneous generation of asymmetric molecular distributions, is a crucial component of many cellular functions. Saccharomyces cerevisiae (yeast) undergoes directed growth during budding and mating, and is an ideal model organism for studying polarization. In yeast and many other cell types, the Rho GTPase Cdc42 is the key molecular player in polarity establishment. During yeast polarization, multiple patches of Cdc42 initially form, then resolve into a single front. Because polarization relies on strong positive feedback, it is likely that the amplification of molecular-level fluctuations underlies the generation of multiple nascent patches. In the absence of spatial cues, these fluctuations may be key to driving polarization. Here we used particle-based simulations to investigate the role of stochastic effects in a Turing-type model of yeast polarity establishment. In the model, reactions take place either between two molecules on the membrane, or between a cytosolic and a membrane-bound molecule. Thus, we developed a computational platform that explicitly simulates molecules at and near the cell membrane, and implicitly handles molecules away from the membrane. To evaluate stochastic effects, we compared particle simulations to deterministic reaction-diffusion equation simulations. Defining macroscopic rate constants that are consistent with the microscopic parameters for this system is challenging, because diffusion occurs in two dimensions and particles exchange between the membrane and cytoplasm. We address this problem by empirically estimating macroscopic rate constants from appropriately designed particle-based simulations. Ultimately, we find that stochastic fluctuations speed polarity establishment and permit polarization in parameter regions predicted to be Turing stable. These effects can operate at Cdc42 abundances expected of yeast cells, and promote polarization on timescales consistent with experimental results. To our knowledge, our work represents the first particle-based simulations of a model for yeast polarization that is based on a Turing mechanism.
    Print ISSN: 1553-734X
    Electronic ISSN: 1553-7358
    Topics: Biology , Computer Science
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  • 88
    Publication Date: 2018-03-13
    Description: by Britta U. Westner, Sarang S. Dalal, Simon Hanslmayr, Tobias Staudigl Single-trial analyses have the potential to uncover meaningful brain dynamics that are obscured when averaging across trials. However, low signal-to-noise ratio (SNR) can impede the use of single-trial analyses and decoding methods. In this study, we investigate the applicability of a single-trial approach to decode stimulus modality from magnetoencephalographic (MEG) high frequency activity. In order to classify the auditory versus visual presentation of words, we combine beamformer source reconstruction with the random forest classification method. To enable group level inference, the classification is embedded in an across-subjects framework. We show that single-trial gamma SNR allows for good classification performance (accuracy across subjects: 66.44%). This implies that the characteristics of high frequency activity have a high consistency across trials and subjects. The random forest classifier assigned informational value to activity in both auditory and visual cortex with high spatial specificity. Across time, gamma power was most informative during stimulus presentation. Among all frequency bands, the 75 Hz 95 Hz band was the most informative frequency band in visual as well as in auditory areas. Especially in visual areas, a broad range of gamma frequencies (55 Hz 125 Hz) contributed to the successful classification. Thus, we demonstrate the feasibility of single-trial approaches for decoding the stimulus modality across subjects from high frequency activity and describe the discriminative gamma activity in time, frequency, and space.
    Print ISSN: 1553-734X
    Electronic ISSN: 1553-7358
    Topics: Biology , Computer Science
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  • 89
    Publication Date: 2018-03-13
    Description: by Moran Brenner, Lior Lobel, Ilya Borovok, Nadejda Sigal, Anat A. Herskovits Listeria monocytogenes ( Lm ) is a saprophyte and intracellular pathogen. Transition to the pathogenic state relies on sensing of host-derived metabolites, yet it remains unclear how these are recognized and how they mediate virulence gene regulation. We previously found that low availability of isoleucine signals Lm to activate the virulent state. This response is dependent on CodY, a global regulator and isoleucine sensor. Isoleucine-bound CodY represses metabolic pathways including branched-chain amino acids (BCAA) biosynthesis, however under BCAA depletion, as occurs during infection, BCAA biosynthesis is upregulated and isoleucine-unbound CodY activates virulence genes. While isoleucine was revealed as an important input signal, it was not identified how internal levels are controlled during infection. Here we show that Lm regulates BCAA biosynthesis via CodY and via a riboregulator located upstream to the BCAA biosynthesis genes, named Rli60. rli60 is transcribed when BCAA levels drop, forming a ribosome-mediated attenuator that cis -regulates the downstream genes according to BCAA supply. Notably, we found that Rli60 restricts BCAA production, essentially starving Lm , a mechanism that is directly linked to virulence, as it controls the internal isoleucine pool and thereby CodY activity. This controlled BCAA auxotrophy likely evolved to enable isoleucine to serve as a host signal and virulence effector.
    Print ISSN: 1553-7390
    Electronic ISSN: 1553-7404
    Topics: Biology
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  • 90
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    Public Library of Science (PLoS)
    Publication Date: 2018-07-27
    Description: by Edvin Fuglebakk, Nathalie Reuter With remarkable spatial and temporal specificities, peripheral membrane proteins bind to biological membranes. They do this without compromising solubility of the protein, and their binding sites are not easily distinguished. Prototypical peripheral membrane binding sites display a combination of patches of basic and hydrophobic amino acids that are also frequently present on other protein surfaces. The purpose of this contribution is to identify simple but essential components for membrane binding, through structural criteria that distinguish exposed hydrophobes at membrane binding sites from those that are frequently found on any protein surface. We formulate the concepts of protruding hydrophobes and co-insertability and have analysed more than 300 families of proteins that are classified as peripheral membrane binders. We find that this structural motif strongly discriminates the surfaces of membrane-binding and non-binding proteins. Our model constitutes a novel formulation of a structural pattern for membrane recognition and emphasizes the importance of subtle structural properties of hydrophobic membrane binding sites.
    Print ISSN: 1553-734X
    Electronic ISSN: 1553-7358
    Topics: Biology , Computer Science
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  • 91
    Publication Date: 2018-07-27
    Description: by Hugo Cruces-Solís, Zhizi Jing, Olga Babaev, Jonathan Rubin, Burak Gür, Dilja Krueger-Burg, Nicola Strenzke, Livia de Hoz Detecting regular patterns in the environment, a process known as statistical learning, is essential for survival. Neuronal adaptation is a key mechanism in the detection of patterns that are continuously repeated across short (seconds to minutes) temporal windows. Here, we found in mice that a subcortical structure in the auditory midbrain was sensitive to patterns that were repeated discontinuously, in a temporally sparse manner, across windows of minutes to hours. Using a combination of behavioral, electrophysiological, and molecular approaches, we found changes in neuronal response gain that varied in mechanism with the degree of sound predictability and resulted in changes in frequency coding. Analysis of population activity (structural tuning) revealed an increase in frequency classification accuracy in the context of increased overlap in responses across frequencies. The increase in accuracy and overlap was paralleled at the behavioral level in an increase in generalization in the absence of diminished discrimination. Gain modulation was accompanied by changes in gene and protein expression, indicative of long-term plasticity. Physiological changes were largely independent of corticofugal feedback, and no changes were seen in upstream cochlear nucleus responses, suggesting a key role of the auditory midbrain in sensory gating. Subsequent behavior demonstrated learning of predictable and random patterns and their importance in auditory conditioning. Using longer timescales than previously explored, the combined data show that the auditory midbrain codes statistical learning of temporally sparse patterns, a process that is critical for the detection of relevant stimuli in the constant soundscape that the animal navigates through.
    Print ISSN: 1544-9173
    Electronic ISSN: 1545-7885
    Topics: Biology
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  • 92
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    Public Library of Science (PLoS)
    In: PLoS ONE
    Publication Date: 2018-07-27
    Description: by Greg Holmes, Lening Zhang, Joshua Rivera, Ryan Murphy, Claudia Assouline, Lorraine Sullivan, Todd Oppeneer, Ethylin Wang Jabs Activating mutations of fibroblast growth factor receptors (FGFRs) are a major cause of skeletal dysplasias, and thus they are potential targets for pharmaceutical intervention. BMN 111, a C-type natriuretic peptide analog, inhibits FGFR signaling at the level of the RAF1 kinase through natriuretic peptide receptor 2 (NPR2) and has been shown to lengthen the long bones and improve skull morphology in the Fgfr3 Y367C/+ thanatophoric dysplasia mouse model. Here we report the effects of BMN 111 in treating craniosynostosis and aberrant skull morphology in the Fgfr2c C342Y/+ Crouzon syndrome mouse model. We first demonstrated that NPR2 is expressed in the murine coronal suture and spheno-occipital synchondrosis in the newborn period. We then gave Fgfr2c C342Y/+ and Fgfr2c +/+ (WT) mice once-daily injections of either vehicle or reported therapeutic levels of BMN 111 between post-natal days 3 and 31. Changes in skeletal morphology, including suture patency, skull dimensions, and long bone length, were assessed by micro-computed tomography. Although BMN 111 treatment significantly increased long bone growth in both WT and mutant mice, skull dimensions and suture patency generally were not significantly affected. A small but significant increase in the relative length of the anterior cranial base was observed. Our results indicate that the differential effects of BMN 111 in treating various skeletal dysplasias may depend on the process of bone formation targeted (endochondral or intramembranous), the specific FGFR mutated, and/or the specific signaling pathway changes due to a given mutation.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 93
    Publication Date: 2018-07-27
    Description: by Irineu Loturco, Bret Contreras, Ronaldo Kobal, Victor Fernandes, Neilton Moura, Felipe Siqueira, Ciro Winckler, Timothy Suchomel, Lucas Adriano Pereira The capacity to rapidly generate and apply a great amount of force seems to play a key role in sprint running. However, it has recently been shown that, for sprinters, the technical ability to effectively orient the force onto the ground is more important than its total amount. The force-vector theory has been proposed to guide coaches in selecting the most adequate exercises to comprehensively develop the neuromechanical qualities related to the distinct phases of sprinting. This study aimed to compare the relationships between vertically-directed (loaded and unloaded vertical jumps, and half-squat) and horizontally-directed (hip-thrust) exercises and the sprint performance of top-level track and field athletes. Sixteen sprinters and jumpers (including three Olympic athletes) executed vertical jumps, loaded jump squats and hip-thrusts, and sprinting speed tests at 10-, 20-, 40-, 60-, 100-, and 150-m. Results indicated that the hip-thrust is more associated with the maximum acceleration phase (i.e., from zero to 10-m; r = 0.93), whereas the loaded and unloaded vertical jumps seem to be more related to top-speed phases (i.e., distances superior to 40-m; r varying from 0.88 to 0.96). These findings reinforce the mechanical concepts supporting the force-vector theory, and provide coaches and sport scientists with valuable information about the potential use and benefits of using vertically- or horizontally-based training exercises.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 94
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    Public Library of Science (PLoS)
    In: PLoS ONE
    Publication Date: 2018-07-27
    Description: by Pei-Chun Kao, Michaela A. Pierro, Konstantina Booras Cognitive-motor interference, a negative influence on the performance of one or both tasks, is manifested when simultaneously performing a cognitive and a motor task. Motor fatigue reduces the ability of generating a required force level. However, little is known about the effects of motor fatigue on the cognitive-motor dual-tasking performance, an important capability during our daily lives. This study investigated how motor fatigue affects dual-task walking performance. Eighteen healthy younger adults walked on a treadmill under three different conditions: walking only, walking while receiving the Paced Auditory Serial Addition Test (PASAT) or a modified Stroop test before and after a lower-extremity fatiguing exercise. We computed dynamic margins of stability (MOS), step and joint kinematic variability, and short-term local divergence exponent (LDE) of the trunk motion. We found that subjects had similar values of short-term LDE during all conditions, indicating that local stability was not affected by the motor fatigue or dual-task conditions. Compared to the baseline, subjects had significantly greater mean MOS after the fatiguing exercise by walking with greater step length and width while having significantly greater gait variability. In contrast, subjects walked with similar mean MOS but significantly less gait variability during the dual-task conditions, indicating that subjects used different adaptive strategies when walking with motor fatigue and during dual-task conditions. There were no significant differences in the number of errors for the two cognitive tests before and after the fatiguing exercise. The current findings demonstrate that motor fatigue does not affect cognitive but motor performance in younger adults.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 95
    Publication Date: 2018-07-27
    Description: by Insu Lee, Daegyu Kim, Ga-Lahm Park, Tae-Joon Jeon, Sun Min Kim When living tissues are injured, they undergo a sequential process of homeostasis, inflammation, proliferation and maturation, which is called wound healing. The working mechanism of wound healing has not been wholly understood due to its complex environments with various mechanical and chemical factors. In this study, we propose a novel in vitro wound healing model using a microfluidic system that can manipulate the topography of the wound bed. The topography of the extracellular matrix (ECM) in the wound bed is one of the most important mechanical properties for rapid and effective wound healing. We focused our work on the topographical factor which is one of crucial mechanical cues in wound healing process by using various nano-patterns on the cell attachment surface. First, we analyzed the cell morphology and dynamic cellular behaviors of NIH-3T3 fibroblasts on the nano-patterned surface. Their morphology and dynamic behaviors were investigated for relevance with regard to the recovery function. Second, we developed a highly reproducible and inexpensive research platform for wound formation and the wound healing process by combining the nano-patterned surface and a microfluidic channel. The effect of topography on wound recovery performance was analyzed. This in vitro wound healing research platform will provide well-controlled topographic cue of wound bed and contribute to the study on the fundamental mechanism of wound healing.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 96
    Publication Date: 2018-07-27
    Description: by Tilen Koklic, Iztok Urbančič, Irena Zdovc, Majda Golob, Polona Umek, Zoran Arsov, Goran Dražić, Štefan Pintarič, Martin Dobeic, Janez Štrancar Bacterial infections acquired in healthcare facilities including hospitals, the so called healthcare acquired or nosocomial infections, are still of great concern worldwide and represent a significant economical burden. One of the major causes of morbidity is infection with Methicillin Resistant Staphylococcus aureus (MRSA), which has been reported to survive on surfaces for several months. Bactericidal activity of copper-TiO 2 thin films, which release copper ions and are deposited on glass surfaces and heated to high temperatures, is well known even when illuminated with very weak UVA light of about 10 μW/cm 2 . Lately, there is an increased intrerest for one-dimensional TiO 2 nanomaterials, due to their unique properties, low cost, and high thermal and photochemical stability. Here we show that copper doped TiO 2 nanotubes produce about five times more ·OH radicals as compared to undoped TiO 2 nanotubes and that effective surface disinfection, determined by a modified ISO 22196:2011 test, can be achieved even at low intensity UVA light of 30 μW/cm 2 . The nanotubes can be deposited on a preformed surface at room temperature, resulting in a stable deposition resistant to multiple washings. Up to 10 3 microorganisms per cm 2 can be inactivated in 24 hours, including resistant strains such as Methicillin-resistant Staphylococcus aureus (MRSA) and Extended-spectrum beta-lactamase Escherichia coli ( E . coli ESBL). This disinfection method could provide a valuable alternative to the current surface disinfection methods.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 97
    Publication Date: 2018-07-27
    Description: by Tim J. Sloan, Jonna Jalanka, Giles A. D. Major, Shanthi Krishnasamy, Sue Pritchard, Salah Abdelrazig, Katri Korpela, Gulzar Singh, Claire Mulvenna, Caroline L. Hoad, Luca Marciani, David A. Barrett, Miranda C. E. Lomer, Willem M. de Vos, Penny A. Gowland, Robin C. Spiller Background & aims Ingestion of poorly digested, fermentable carbohydrates (fermentable oligo-, di-, mono-saccharides and polyols; FODMAPs) have been implicated in exacerbating intestinal symptoms and the reduction of intake with symptom alleviation. Restricting FODMAP intake is believed to relieve colonic distension by reducing colonic fermentation but this has not been previously directly assessed. We performed a randomised controlled trial comparing the effect of a low FODMAP diet combined with either maltodextrin or oligofructose on colonic contents, metabolites and microbiota. Methods A parallel randomised controlled trial in healthy adults (n = 37). All subjects followed a low FODMAP diet for a week and supplemented their diet with either maltodextrin (MD) or oligofructose (OF) 7g twice daily. Fasted assessments performed pre- and post-diet included MRI to assess colonic volume, breath testing for hydrogen and methane, and stool collection for microbiota analysis. Results The low FODMAP diet was associated with a reduction in Bifidobacterium and breath hydrogen, which was reversed by oligofructose supplementation. The difference in breath hydrogen between groups post-intervention was 27ppm (95% CI 7 to 50, P
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 98
    Publication Date: 2018-07-27
    Description: by Geethika Reddi, Kali Pruss, Kathryn L. Cottingham, Ronald K. Taylor, Salvador Almagro-Moreno Vibrio cholerae O1, the etiological agent of cholera, is a natural inhabitant of aquatic ecosystems. Motility is a critical element for the colonization of both the human host and its environmental reservoirs. In this study, we investigated the molecular mechanisms underlying the chemotactic response of V . cholerae in the presence of some of its environmental reservoirs. We found that, from the several oligosaccharides found in mucin, two specifically triggered motility of V . cholerae O1: N -acetylneuraminic acid (Neu5Ac) and N -acetylglucosamine (GlcNAc). We determined that the compounds need to be internally catabolized in order to trigger motility of V . cholerae . Interestingly, the catabolism of Neu5Ac and GlcNAc converges and the production of one molecule common to both pathways, glucosamine-6-phosphate (GlcN-6P), is essential to induce motility in the presence of both compounds. Mutants unable to produce GlcN-6P show greatly reduced motility towards mucin. Furthermore, we determined that the production of GlcN-6P is necessary to induce motility of V . cholerae in the presence of some of its environmental reservoirs such as crustaceans or cyanobacteria, revealing a molecular link between the two distinct modes of the complex life cycle of V . cholerae . Finally, cross-species comparisons revealed varied chemotactic responses towards mucin, GlcNAc, and Neu5Ac for environmental (non-pathogenic) strains of V . cholerae , clinical and environmental isolates of the human pathogens Vibrio vulnificus and Vibrio parahaemolyticus , and fish and squid isolates of the symbiotic bacterium Vibrio fischeri . The data presented here suggest nuance in convergent strategies across species of the same bacterial family for motility towards suitable substrates for colonization.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 99
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    Public Library of Science (PLoS)
    In: PLoS ONE
    Publication Date: 2018-07-27
    Description: by Anne C. Wheeler, Camila V. Ventura, Ty Ridenour, Danielle Toth, Lucélia Lima Nobrega, Lana Claudia Silva de Souza Dantas, Camilla Rocha, Donald B. Bailey Jr., Liana O. Ventura The recent Zika outbreak and its link to microcephaly and other birth defects in infants exposed in utero have garnered widespread international attention. Based on the severity of birth defects the extent of impairment in these infants is expected to be profound; however, virtually nothing is known regarding the developmental and behavioral sequela of congenital Zika syndrome. This pilot study collected parent-reported patterns of development and sleep in 47 infants with confirmed congenital Zika syndrome who are being followed for clinical services at the Altino Ventura Foundation (FAV) in Recife, Brazil. With assistance from clinicians at FAV, caregivers completed Brazilian Portuguese versions of the Ages and Stages Questionnaire, 3 rd edition (ASQ-3) and the Brief Infant Sleep Questionnaire (BISQ). All infants were between 13–22 months of age at the time of the assessment. At 16 months of age, none of the children displayed age appropriate developmental skills. Most (~ 75%) mastered some communication and gross motor skills at around a 6–8-month level. Communication and gross motor skills were relative strengths for the sample, while problem-solving and fine motor skills were relative weaknesses. Sleep was noted to be a problem for around 18% of the sample. In utero exposure to the Zika virus will have lifelong consequences for affected children and their families. Understanding the developmental and behavioral trajectories of affected infants will help identify appropriate family supports to improve quality of life.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 100
    Publication Date: 2018-07-27
    Description: by Veronique Deschodt-Arsac, Romain Lalanne, Beatrice Spiluttini, Claire Bertin, Laurent M. Arsac Introduction Heart rate variability biofeedback (HRV-BFB) training, a method whereby one controls an unusually low breathing rate to reach cardiac coherence, has been shown to reduce anxiety and improve cardiac autonomic markers in diseased people, but much less is known about HRV-BFB benefits in healthy people. Here we investigated potential benefits in young competitors experiencing stress during university examinations as well as persistence of benefits after HRV-BFB training cessation. Methods A group of sports students (n = 12) practiced 5-min HRV-BFB training twice a day for 5-weeks using URGOfeel ® (URGOTECH) and was compared to a control group (n = 6). University examinations occurred immediately after HRV-BFB training (Exam1), then 12-weeks later (Exam2). Anxiety markers and cardiac autonomic markers were assessed at baseline, Exam1 and Exam2. Principal Component Analyses (PCA) that combined all these markers were computed at Exam1 and Exam2 to emphasize covariations. Results At Exam 1, immediately after HRV-BFB training cessation, the experimental group demonstrated greater autonomic markers but similar states of anxiety when compared to the Control group. Twelve weeks later at Exam2, autonomic markers were greater and anxiety scores were lesser among the experimental group. PCA highlighted covariations only within cardiac autonomic markers at Exam1. Rather, variations in cardiac markers were associated with anxiety markers at Exam2. Conclusion Short sessions of HRV-BFB training for a brief period of 5 weeks bring substantial benefits to autonomic markers and anxiety levels in young competitors. Here beneficial effects persisted for 12 weeks. Dissociated profiles of anxiety and cardiac autonomic adaptations shed new light on the role of the amygdala in heart-brain interactions after cardiac coherence training.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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