bluuebunny/crossref_metadata_2025 huggingface dataset:
Balanced internal hydration discriminates substrate binding to respiratory complex I
Authors: Teixeira Murilo Hoias , Arantes Guilherme Menegon
Published: March 2019

Molecular recognition of the amphiphilic electron carrier ubiquinone (Q) by respiratory complexes is a fundamental part of electron transfer chains in mitochondria and many bacteria. The primary respiratory complex I binds Q in a long and narrow protein chamber to catalyse its reduction. But, the binding mechanism and the role of chamber hydration in substrate selectivity and stability are unclear. Here, large-scale atomistic molecular dynamics simulations and estimated free energy profiles are used to characterize in detail the binding mechanism to complex I of Q with short and with long isoprenoid tails. A highly stable binding site with two different poses near the chamber exit and a secondary reactive site near the N2 iron-sulfur cluster are found which may lead to an alternative Q redox chemistry and help to explain complex I reactivity. The binding energetics depends mainly on polar interactions of the Q-head and on the counterbalanced hydration of Q-tail isoprenoid units and hydrophobic residues inside the protein chamber. Selectivity upon variation of tail length arises by shifting the hydration balance. This internal hydration mechanism may have implications for binding of amphiphilic molecules to cavities in other membrane proteins.
Global motion processing by populations of direction-selective retinal ganglion cells
Authors: Cafaro Jon , Zylberberg Joel , Field Greg
Published: March 2019

Simple stimuli have been critical to understanding neural population codes in sensory systems. Yet it remains necessary to determine the extent to which this understanding generalizes to more complex conditions. To explore this problem, we measured how populations of direction-selective ganglion cells (DSGCs) from mouse retina respond to a global motion stimulus with its direction and speed changing dynamically. We then examined the encoding and decoding of motion direction in both individual and populations of DSGCs. Individual cells integrated global motion over ~200 ms, and responses were tuned to direction. However, responses were sparse and broadly tuned, which severely limited decoding performance from small DSGC populations. In contrast, larger populations compensated for response sparsity, enabling decoding with high temporal precision (<100 ms). At these timescales, correlated spiking was minimal and had little impact on decoding performance, unlike results obtained using simpler local motion stimuli decoded over longer timescales. We use these data to define different DSGC population decoding regimes that utilize or mitigate correlated spiking to achieve high spatial versus high temporal resolution.
Insect—symbiont gene expression in the midgut bacteriocytes of a blood-sucking parasite
Authors: Filip Husnik , Vaclav Hypsa , Alistair Darby
Published: March 2019

Background

Animals interact with a diverse array of both beneficial and detrimental microorganisms. These interactions sometimes spark obligate symbioses where the host depends on beneficial bacteria for survival and reproduction. In insects, these obligate symbioses in many cases allow feeding on nutritionally unbalanced diets such as plant sap and vertebrate blood. It is, however, still not clear how are these obligate intracellular symbioses maintained at the cellular level for up to several hundred million years. Exact mechanisms driving host-symbiont interactions are only understood for a handful of model species and data on blood-feeding hosts with intracellular bacteria are particularly scarce.

Results

Here, we analyzed interactions at the symbiotic interfaces of an obligately blood-sucking parasite of sheep, the louse flyMelophagus ovinus. We assembled a reference transcriptome from one male and one female individual and used RNA-Seq with five biological replicates to compare expression in the midgut cells housing bacteria to the rest of the gut (foregut-hindgut). We focused on nutritional and immunity interactions between the insect host and its obligate symbiontArsenophonus melophagi, and also generated lower-coverage data for three facultative bacterial symbionts (Sodalis melophagi, Bartonella melophagi, andWolbachiasp.) and one facultative eukaryoteTrypanosoma melophagium. We found strong evidence for the importance of zinc in the system likely caused by symbionts using zinc-dependent proteases when acquiring amino acids, and for likely different immunity mechanisms controlling the symbionts than in closely related tsetse flies.

Conclusions

Our results show that cellular and nutritional interactions between this blood-sucking insect and its symbionts are less intimate than what was previously found in some (but not all) plant-sap sucking insects such as aphids, psyllids, whiteflies, and mealybugs. This finding is likely interconnected to several features observed in symbionts in blood-sucking arthropods, particularly their midgut intracellular localization (as opposed to being localized in truly specialized bacteriocytes), intracytoplasmic presence (as opposed to having an outermost host-derived ‘symbiosomal’ membrane), less severe genome reduction, and relatively recent associations caused by frequent evolutionary losses and replacements.

Data deposition

Raw RNA-Seq data were made available through the European Nucleotide Archive (ENA) database under the study accession number PRJEB30632. All assemblies and additional large supplementary files are available on FigShare [https://doi.org/10.6084/m9.figshare.6146777.v1]. All commands used for data analyses are available on Github [https://github.com/filip-husnik/melophagus].
The orientation of a membrane probe from structural analysis by enhanced Raman scattering
Authors: Hughes Hannah J. , Demers Steven M. E. , Zhang Aobo , Hafner Jason H.
Published: March 2019

Small fluorescent molecules are widely used as probes of biomembranes. Different probes optically indicate membrane properties such as the lipid phase, thickness, viscosity, and electrical potential. The detailed molecular mechanisms behind probe signals are not well understood, in part due to the lack of tools to determine probe position and orientation in the membrane. Optical measurements on aligned biomembranes and lipid bilayers provide some degree of orientational information based on anisotropy in absorption, fluorescence, or nonlinear optical properties. These methods typically find the polar tilt angle between the membrane normal and the long axis of the molecule. Here we show that solution-phase surface enhanced Raman scattering (SERS) spectra of lipid membranes on gold nanorods can be used to determine molecular orientation of molecules within the membrane. The voltage sensitive dye 4-(2-(6-(dibutylamino)-2-naphthalenyl)ethenyl)-1-(3-sulfopropyl)-hydroxide, known as di-4-ANEPPS, is studied. Through the analysis of several peaks in the SERS spectrum, the polar angle from the membrane normal is found to be 63°, and the roll angle around the long axis of the molecule to be 305° from the original orientation. This structural analysis method could help elucidate the meaning of fluorescent membrane probe signals, and how they are affected by different lipid compositions.
COMMD1 and PtdIns(4,5)P2 interaction maintain ATP7B copper transporter trafficking fidelity in HepG2 cells
Authors: Stewart Davis J. , Short Kristopher K. , Maniaci Breanna N. , Burkhead Jason L.
Published: March 2019

Copper-responsive intracellular ATP7B trafficking is critical to maintain copper balance in mammalian hepatocytes and thus organismal copper levels. The COMMD1 protein binds both the ATP7B copper transporter and phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2), while COMMD1 loss causes hepatocyte copper accumulation. Although it is clear that COMMD1 is included in endocytic trafficking complexes, a direct function for COMMD1 in ATP7B trafficking has not been defined. In this study, experiments using quantitative reveal that COMMD1 modulates the copper-responsive ATP7B trafficking through recruitment to PtdIns(4,5)P2. Decreased COMMD1 abundance results in loss of ATP7B from lysosomes and thetrans-Golgi network (TGN) in high copper conditions, while excess expression of COMMD1 also disrupts ATP7B trafficking and TGN structure. Overexpression of COMMD1 mutated to inhibit PtdIns(4,5)P2binding has little impact on ATP7B trafficking. A mechanistic PtdIns(4,5)P2-mediated function for COMMD1 is proposed that is consistent with decreased cellular copper export due to disruption of the ATP7B trafficking itinerary and accumulation in the early endosome when COMMD1 is depleted. PtdIns(4,5)P2interaction with COMMD1 as well as COMMD1 abundance may both be important in maintenance of specific membrane protein trafficking pathways.

Quantitative analysis of 3D protein colocalization defines the cellular function of COMMD1 in maintenance of ATP7B copper transporter trafficking fidelity and the importance of PtdIns(4,5)P2in this action.
Associations among Fish Length, Dam Passage History, and Survival to Adulthood in Two At-Risk Species of Pacific Salmon
Authors: Faulkner James R. , Bellerud Blane L. , Widener Daniel L. , Zabel Richard W.
Published: March 2019

Threatened or endangered salmon and steelhead originating in the Snake River basin must pass through a series of eight major hydroelectric dams during their seaward migration. Understanding the effects of specific dam passage routes on lifetime survival for these stocks is essential for successful management. Juvenile fish may pass these dams via three primary routes: 1) spillways; 2) turbines; or 3) juvenile bypass systems, which divert fish away from turbines and route them downstream. Bypass systems may expose fish to trauma, increased stress, or disease. However, numerous studies have indicated that direct survival through bypass systems is comparable to and often higher than that through spillways. Some researchers have suggested that route of dam passage affects mortality in the estuary or ocean, but this is complicated by studies finding fish size affects route of passage. We tested whether passage through bypass systems was associated with probability of adult return after accounting for fish length and other covariates for two species of concern. We also investigated the association between fish length and probability of bypass at dams, and how this relationship could lead to spurious conclusions regarding effects of bypass systems on survival if length was ignored. We found that: 1) larger fish had lower bypass probabilities at 6 of 7 dams; 2) larger fish had higher probability of surviving to adulthood; 3) bypass history had little association with adult return after accounting for length; and 4) simulations indicated spurious effects of bypass on survival may arise when no true bypass effect exists, especially in models without length. Our results suggest that after fish leave the hydropower system, bypass passage history has little effect on mortality. Our findings underscore the importance of accounting for fish size in studies of dam passage or survival.
In search of Universal Cortical Power Changes Linked to NMDA-Antagonist based Anesthetic Induced Reductions in Consciousness
Authors: Pelentritou Andria , Kuhlmann Levin , Cormack John , Mcguigan Steven , Woods Will , Muthukumaraswamy Suresh , Liley David
Published: March 2019

B. Abstract

Background.

Despite their intriguing nature, investigations of the neurophysiology of N-methyl-D-aspartate (NMDA)-antagonists Xenon (Xe) and nitrous oxide (N2O) are limited and have revealed inconsistent frequency-dependent alterations, in spectral power and functional connectivity. Discrepancies are likely due to using low resolution electroencephalography restricted to sensor level changes, concomitant anesthetic agent administration and dosage. Our intention was to describe the effects of equivalent stepwise levels of Xe and N2O administration on oscillatory source power using a crossover design, to explore universal mechanisms of NMDA-based anesthesia.

Methods.

22 healthy males participated in a study of simultaneous magnetoencephalography and electroencephalography recordings. In separate sessions, equivalent subanesthetic doses of gaseous anesthetic agents N2O and Xe (0.25, 0.50, 0.75 equi MAC-awake) and 1.30 MAC-awake Xe (for Loss of Responsiveness) were administered. Source power in various frequency bands was computed and statistically assessed relative to a conscious baseline.

Results.

Delta (l-4Hz) and theta (4-8Hz) band power was significantly increased at the highest Xe concentration (42%, 1.30 MAC-awake) relative to baseline for both magnetoencephalography and electroencephalography source power (p<0.005). A reduction in frontal alpha (8-13 Hz) power was observed upon N2O administration, and shown to be stronger than equivalent Xe dosage reductions (p=0.005). Higher frequency activity increases were observed in magnetoencephalographic but not encephalographic signals for N2O alone with occipital low gamma (30-49Hz) and widespread high gamma (51-99Hz) rise in source power.

Conclusions.

Magnetoencephalography source imaging revealed unequivocal and widespread power changes in dissociative anesthesia, which were divergent to source electroencephalography. Loss of Responsiveness anesthesia at 42% Xe (1.30 MAC-awake) demonstrated, similar to inductive agents, low frequency power increases in frontal delta and global theta. N2O sedation yielded a rise in high frequency power in the gamma range which was primarily occipital for lower gamma bandwidth (3049 Hz) and substantially decreased alpha power, particularly in frontal regions.

Clinical trial number and Registry URL

Not applicable.

Prior Presentations

Pelentritou Andria, Kuhlmann Levin; Lee Heonsoo; Cormack John; Mcguigan Steven; Woods Will; Sleigh Jamie; Lee UnCheol; Muthukumaraswamy Suresh; Liley David. Searching For Universal Cortical Power Changes Linked To Anesthetic Induced Reductions In Consciousness. The Science of Consciousness April 4th2018. Tucson, Arizona, USA.

Summary Statement

Not applicable.
The shape of gene expression distributions matter: how incorporating distribution shape improves the interpretation of cancer transcriptomic data
Authors: Torrenté Laurence de , Zimmerman Samuel , Suzuki Masako , Christopeit Maximilian , Greally John M. , Mar Jessica C.
Published: March 2019

In genomics, we often impose the assumption that gene expression data follows a specific distribution. However, rarely do we stop to question this assumption or consider its applicability to all genes in the transcriptome. Our study investigated the prevalence of genes with expression distributions that are non-Normal in three different tumor types from the Cancer Genome Atlas (TCGA). Surprisingly, less than 50% of all genes were Normally-distributed, with other distributions including Gamma, Bimodal, Cauchy, and Lognormal were represented. Relevant information about cancer biology was captured by the genes with non-Normal gene expression. When used for classification, the set of non-Normal genes were able to discriminate between cancer patients with poor versus good survival status. Our results highlight the value of studying a gene’s distribution shape to model heterogeneity of transcriptomic data. These insights would have been overlooked when using standard approaches that assume all genes follow the same type of distribution in a patient cohort.
De novo missense variant in the GTPase effector domain (GED) of DNM1L leads to static encephalopathy and seizures
Authors: Assia Batzir Nurit , Bhagwat Pranjali K. , Eble Tanya N. , Liu Pengfei , Eng Christine M. , Elsea Sarah H. , Robak Laurie A. , Scaglia Fernando , Goldman Alica M. , Dhar Shweta U. , Wangler Michael F.
Published: March 2019

DNM1L encodes a GTPase of the dynamin superfamily, which plays a crucial role in mitochondrial and peroxisomal fission. Pathogenic variants affecting the middle domain and the GTPase domain of DNM1L have been implicated in encephalopathy because of defective mitochondrial and peroxisomal fission 1 (EMPF1, MIM #614388). Patients show variable phenotypes ranging from severe hypotonia leading to death in the neonatal period to developmental delay/regression, with or without seizures. Familial pathogenic variants in the GTPase domain have also been associated with isolated optic atrophy. We present a 27-yr-old woman with static encephalopathy, a history of seizures, and nystagmus, in whom a novel de novo heterozygous variant was detected in the GTPase effector domain (GED) of DNM1L (c.2072A>G, p.Tyr691Cys). Functional studies in Drosophila demonstrate large, abnormally distributed peroxisomes and mitochondria, an effect very similar to that of middle domain missense alleles observed in pediatric subjects with EMPF1. To our knowledge, not only is this the first report of a disease-causing variant in the GED domain in humans, but this is also the oldest living individual reported with EMPF1. Longitudinal data of this kind helps to expand our knowledge of the natural history of a growing list of DNM1L-related disorders.
Serum antibody profiles in individuals with latent Mycobacterium tuberculosis infection
Authors: Maekura Ryoji , Kitada Seigo , Osada‐Oka Mayuko , Tateishi Yoshitaka , Ozeki Yuriko , Fujicawa Takeya , Miki Mari , Jyunnko Ogawa , Mori Masahide , Matsumoto Sohkichi
Published: March 2019

One‐third of the world's humans has latent tuberculosis infection (LTBI), representing a large pool of potentially active TB. Recent LTBI carries a higher risk of disease progression than remote LTBI. Recent studies suggest important roles of antibodies in TB pathology, prompting us to investigate serum antibody profiles in a cohort with LTBI. In this single‐center prospective observational study, we analyzed IgG‐antibody concentrations against five major Mycobacterium tuberculosis (Mtb) antigens (including 6 kDa early secretory antigenic target (ESAT6), CFP10, and antigen 85A, which are expressed mainly in the growth phase; and mycobacterial DNA‐binding protein 1 (MDP1) and alpha‐crystallin like protein (Acr), which are expressed in the dormant phases) in individuals with recent (n=13) or remote (n=12) LTBI, no Mtb infection (n=19), or active TB (n=15). Antibody titers against ESAT6 and MDP1 were significantly higher in individuals with recent LTBI than in those with no Mtb infection or remote LTBI. All pairwise antibody titers against these five major antigens were significantly correlated throughout the stages of Mtb infection. Five individuals with recent LTBI had significantly higher antibody titers against ESAT6 (P = 0.03), Ag85A (P = 0.048), Acr (P = 0.057), and MDP1 (P = 0.0001) than in individuals with remote LTBI; they were also outside the normal range (+2 SDs). One of these individuals was diagnosed with active pulmonary TB at 18‐month follow‐up examination. These findings indicated that concentrations of antibodies against both multiplying and dormant Mtb are higher in recent LTBI and that individuals with markedly higher antibody titers may be appropriate candidates for prophylactic therapy.
Association of interleukin‐17 gene polymorphisms and susceptibility to brucellosis in Hamadan, western Iran
Authors: Keramat Fariba , Kazemi Sima , Saidijam Massoud , Zamani Alireza , Kohan Hamed Farhdi , Mamani Mojgan , Eini Peyman , Moghimbigi Abbas , Alikhani Mohammad Yousef
Published: March 2019

IL‐17is one of the most important inflammatory cytokines that stimulate immunity responses in humans infected with Brucella species, acting as a regulator that reduces release of γ‐IFN, thus increasing resistance to brucellosis. Gene polymorphisms in the regulatory regions of cytokine‐encoding genes affect the amountsof cytokines produced and play a fundamental role in infectious diseases. The aim of this study was to determine the association between IL‐17 gene polymorphisms and susceptibility to brucellosis. In this case‐control study, 86 patients with brucellosis and 86 healthy persons in Hamadan, western Iran, from September 2014 to September 2016, were included. IL‐17 genetic variants at positions rs4711998 A/G, rs8193036 C/T, rs3819024 A/G, rs2275913 A/G, rs3819025 A/G, rs8193038 A/G, rs3804513 A/T, rs1974226 A/G and rs3748067 A/G were analyzed by restriction fragment length polymorphism‐PCR. Serum IL‐17 titers were measured by sandwich ELISA. GG genotypes at positions rs4711998 and rs3748067 were present significantly more frequently in patients with brucellosis than in controls (P < 0.05). The AA genotype at positions rs4711998, rs2275913 and rs3748067 and GG genotype at position rs19744226 were present significantly more frequently in controls than in the patient group. These results suggest that the AA genotype at positions rs3748067, rs3819025 and rs4711998 and GG genotype at position rs3819024 are likely protective factors against brucellosis, whereas the GG genotype at positions rs3748067, rs3819025 and rs4711998 and AA genotype at position rs3819024 may be risk factors against the disease. No significant relationships were found between serum IL‐17 titers and genotypes of the single‐nucleotide polymorphisms.
Insect acoustic communication: The role of transmission channel and the sensory system and brain of receivers
Authors: Römer Heiner
Published: March 2019

For decades, acoustic insects have been used as model organisms for behavioural neurobiologists to understand mate choice or predator avoidance, because behaviour can easily and reliably be elicited in the laboratory, and behaviourally relevant, identified nerve cells be studied under these conditions. However, signalling often takes place in complex environments, in which the signal perceived by the receiver may differ greatly from the one broadcast due to the biotic and abiotic properties of the sound transmission channel. Thus, the key challenge is to transfer the insights of these laboratory‐oriented experiments to more natural settings.

Signal detection, identification and discrimination, as well as localization, are complicated by the transmission channel in several ways. Here, I review the empirical evidence from outdoor studies, demonstrating how excess attenuation reduces the active space and the information of a signal at some distance from the sender. At the same time, these frequency‐dependent processes allow to maintain acoustic distances to neighbours in a population.

Insects often communicate within choruses of signallers of the same and different species, giving rise to high levels of acoustic masking interference. I discuss the evidence found for temporal or spatial partitioning of species in multispecies assemblages, and I show that solutions to the masking problem are based on a combination of adaptations in the behaviour of signallers and in the sensory system of receivers.

Whether or not the perceived signal elicits a behaviour in receivers will depend on the design of the sensory system and the brain. I give examples for active mechanical processes in insect sensory receptors that influence the responses to external stimuli. In addition, neuronal filters in the frequency, intensity or time domain, and even the memory of individual receivers, provide the basis for adaptive receiver decision‐making in mate choice scenarios.

Finally, I describe the advantages of having access to the relatively simple nervous systems of insects and how this access, combined with the use of a variety of behavioural tests, allows new insights into acoustic communication and its evolution.

A free Plain Language Summary can be found within the Supporting Information of this article.
Patchy delivery of functions undermines functional redundancy in a high diversity system
Authors: Streit Robert P. , Cumming Graeme S. , Bellwood David R.
Published: March 2019

Globally, many ecosystems are being challenged and transformed by anthropogenic climate change. Future ecosystem configurations will be heavily influenced by the critical ecological functions that affect resilience. Robust measures of these functions will thus be essential for understanding and responding to ecological change.

Coral reefs are experiencing unprecedented ecological change due to global mass coral bleaching. After bleaching events and other disturbances, herbivorous fishes provide functions that are critical for reef resilience by controlling harmful proliferation of algae. Identifying functional diversity amongst herbivorous fishes has been a mainstay of reef fish research, but it has remained unclear how, and to what extent, functional diversity translates to functional impacts on reefs.

Rather than assessing the functional potential of the herbivorous fish community, we explicitly considered the delivery of herbivory to the reef by quantifying, in unprecedented detail, the spatial extent and overlap of feeding areas across different functional groups. Core feeding areas were highly concentrated and consistently covered just 14% of available reef space. Overlap across functional groups was limited, showing high spatial complementarity as functional groups tended to feed next to one another. Thus, the delivery of critical ecosystem processes was patchy, effectively reducing functional redundancy, even in the presence of a diverse fish assemblage.

Our findings caution against assumptions of spatial homogeneity in the delivery of critical ecosystem functions. The functional impact of local herbivorous fish assemblages in current approaches may be overestimated, potentially leading to skewed assessments of reef resilience. Our results highlight the need to incorporate collective animal behaviour and spatio‐temporal scales into future assessments of ecosystem functions and ultimately ecological resilience.

A plain language summary is available for this article.
Specialized roots of Velloziaceae weather quartzite rock while mobilizing phosphorus using carboxylates
Authors: Teodoro Grazielle Sales , Lambers Hans , Nascimento Diego L. , de Britto Costa Patrícia , Flores‐Borges Denisele N. A. , Abrahão Anna , Mayer Juliana L. S. , Sawaya Alexandra C. H. F. , Ladeira Francisco Sérgio Bernardes , Abdala Dalton Belchior , Pérez Carlos A. , Oliveira Rafael S.
Published: March 2019

Campos rupestres is an extremely phosphorus (P)‐impoverished rocky ecosystem in Brazil. Velloziaceae is an important plant family in this environment, and some species colonize exposed quartzite rock. However, we know virtually nothing about their root development and nutrient acquisition within the rock outcrops and their possible role in rock weathering and landscape formation.

We tested the hypothesis that Velloziaceae dissolve P from the rock, enhancing rock weathering. The study was carried out with two Barbacenia species (Velloziaceae) that colonize quartzite rocks. We assessed the root specializations and exudates, and determined the mineralogical composition of the rocks.

The quartzite rocks contained a low concentration of total P in a matrix composed predominantly of silica. Using transmission electron microscopy, we show root growth perpendicular to the rock‐bedding planes. A micro‐XRF set‐up at the XRF beamline of a synchrotron evidenced root‐associated rock dissolution.

The investigated roots show novel morphological and physiological specializations, coined vellozioid roots, which are highly effective at P acquisition. These carboxylate‐releasing roots function like other specialized roots in nutrient‐depleted soils. The rocks represent a barrier for most species, but due to their chemical and physical actions inside the rocks, vellozioid roots play a pivotal role in rock weathering, contributing to shaping the campos rupestres landscapes.

A plain language summary is available for this article.
Multi‐species duck harvesting using dynamic programming and multi‐criteria decision analysis
Authors: Johnson Fred A. , Zimmerman Guthrie S. , Huang Min T. , Padding Paul I. , Balkcom Gregory D. , Runge Michael C. , Devers Patrick K.
Published: March 2019

Multiple species are often exposed to a common hunting season, but harvest and population objectives may not be fully achieved if harvest potential varies among species and/or species abundances are not correlated through time. Our goal was to develop an approach for setting a common hunting season that would recognize heterogeneity in species productivity and would select annual hunting seasons conditioned on the status of individual species.

We first used stochastic dynamic programming to generate optimal, state‐dependent harvest strategies for 18 candidate regulatory scenarios. We simulated the performance of these strategies, and then used multi‐criteria decision analysis to identify preferred regulatory scenarios for duck hunting seasons in the Atlantic Flyway of the U.S.

Generally, estimates of annual population size were not correlated among species. Mallards had the highest estimated intrinsic rate of growth, green‐winged teal, wood ducks, and ring‐necked ducks had intermediate values, and goldeneyes were the least productive. Estimated carrying capacity was highest for mallards and lowest for green‐winged teal.

Managers had greatest interest in maximizing season length (33%) and aggregate duck abundance (28%), and less interest in maximizing aggregate harvest (19%) and the number of years between a change in hunting season regulations (19%). Several regulatory scenarios provided acceptable trade‐offs among these objectives.

Synthesis and applications. Separate hunting seasons for various species of game may be untenable, either due to the added cost and regulatory complexity, or because selective harvesting of stocks may be difficult due to problems in species identification. Rather than averaging species‐specific productivities, or basing hunting seasons on the least (or most) productive species, we describe an approach in which productivity and annual population status are considered explicitly for each species. By combining stochastic dynamic programming with multi‐criteria decision analysis, we can identify a regulatory strategy that can address a diverse set of objectives and explicitly recognize the trade‐offs among them. To meet the Atlantic Flyway's objectives as identified by waterfowl managers, our results suggest a regulatory strategy in which the harvest is targeted at 98% of aggregate maximum sustainable yield, most emphasis is placed on accumulating harvests of mallards and wood ducks, and by using a set of regulatory options that are more conservative than those currently in use.
Failure to coordinate management in transboundary populations hinders the achievement of national management goals: The case of wolverines in Scandinavia
Authors: Gervasi Vincenzo , Linnell John D. C. , Brøseth Henrik , Gimenez Olivier
Published: March 2019

Large carnivores are expanding in Europe, and their return is associated with conflicts that often result in policies to regulate their population size through culling. Being wide‐ranging species, their populations are often distributed across several jurisdictions, which may vary in the extent to which they use lethal control. This creates the conditions for the establishment of source‐sink dynamics across borders, which may frustrate the ability of countries to reach their respective management objectives.

To explore the consequences of this issue, we constructed a vec‐permutation projection model, applied to the case of wolverines in south‐central Scandinavia, shared between Norway (where they are culled) and Sweden (where they are protected). We evaluated the effect of compensatory immigration on wolverine population growth rates, and if the effect was influenced by the distance to the national border. We assessed to what extent compensatory immigration had an influence on the number of removals needed to keep the population at a given growth rate.

In Norway, the model estimated a stable trend, whereas in Sweden it produced a 10% annual increase. The effect of compensatory immigration corresponded to a 0.02 reduction in population growth rate in Sweden and to a similar increase in Norway. This effect was strong closer to the Norwegian‐Swedish border, but weak when moving away from it. An average of 33 wolverines was shot per year in the Norwegian part of the study area. If no compensatory immigration from Sweden had occurred, 28 wolverines shot per year would have been sufficient to achieve the same goal. About 15.5% of all the individuals harvested in Norway between 2005 and 2012 were compensated by immigrants, causing a decrease in population growth rate in Sweden.

Synthesis and applications. When a population is transboundary, the consequences of management decisions are also transboundary, even though the political bodies in charge of those decisions, the stakeholders who influence them, and the taxpayers who finance them are not. It is important that managers and citizens be informed that a difference in management goals can reduce the efficiency, and increase the costs, of wildlife management.
Mycorrhizal symbioses and the evolution of trophic modes in plants
Authors: Jacquemyn Hans , Merckx Vincent S. F. T.
Published: March 2019

Since the early colonization of land, plants depend, to various extents, on mycorrhizal fungi to meet their nutrient demands. In most mycorrhizal symbioses, plants provide sugars derived from photosynthesis to the fungi, whereas the fungi provide essential minerals to the plant. However, in some plants, the flow of carbon has reversed and the fungi provide carbon to the plants. These plants are called mycoheterotrophs. However, it remains unclear how and under which circumstances trophic modes change and whether transitions in trophic modes are associated with changes in mycorrhizal communities.

Here, we review the available literature on mycorrhizal associations and trophic modes in plants. We first outline how trophic modes can be determined and how they differ across plants. We then investigate the evolutionary context under which mycoheterotrophy originated. We also examine the mycorrhizal communities associating with autotrophic, partially mycoheterotrophic and fully mycoheterotrophic plants within different plant families and investigate whether commonalities can be observed.

Our overview shows that mycoheterotrophy has originated more than 40 times through evolutionary time and can be found in a wide range of plant groups, including liverworts, lycophytes, ferns, monocots and dicots. Partial mycoheterotrophy appears to be much more common than previously anticipated and represents an almost continuous gradient between autotrophy and full mycoheterotrophy.

Comparison of the mycorrhizal communities associating with autotrophic, partial and full mycoheterotrophic plants indicates that, although they share some commonalities, shifts from autotrophy to full mycoheterotrophy are accompanied by either losses or shifts in mycorrhizal partners, suggesting that full or partial loss of photosynthesis selects for different mycorrhizal communities.

Synthesis. Partial mycoheterotrophy appears to be much more common than previously thought and represents an almost continuous gradient from autotrophy to full mycoheterotrophy. Evolution to full mycoheterotrophy is challenging as it requires specific adaptations and often a switch to other mycorrhizal partners. More detailed analyses of the functionality of different mycorrhizal systems co‐occurring in the roots of a single plant and the costs of mycorrhizal switching are needed to understand the precise mechanisms leading to full mycoheterotrophy.
Metagenomic analysis reveals distinct patterns of denitrification gene abundance across soil moisture, nitrate gradients
Authors: Nadeau Sarah A. , Roco Constance A. , Debenport Spencer J. , Anderson Todd R. , Hofmeister Kathryn L. , Walter M. Todd , Shapleigh James P.
Published: March 2019

This study coupled a landscape‐scale metagenomic survey of denitrification gene abundance in soils with in situ denitrification measurements to show how environmental factors shape distinct denitrification communities that exhibit varying denitrification activity. Across a hydrologic gradient, the distribution of total denitrification genes (nap/nar + nirK/nirS + cNor/qNor + nosZ) inferred from metagenomic read abundance exhibited no consistent patterns. However, when genes were considered independently, nirS, cNor and nosZ read abundance was positively associated with areas of higher soil moisture, higher nitrate and higher annual denitrification rates, whereas nirK and qNor read abundance was negatively associated with these factors. These results suggest that environmental conditions, in particular soil moisture and nitrate, select for distinct denitrification communities that are characterized by differential abundance of genes encoding apparently functionally redundant proteins. In contrast, taxonomic analysis did not identify notable variability in denitrifying community composition across sites. While the capacity to denitrify was ubiquitous across sites, denitrification genes with higher energetic costs, such as nirS and cNor, appear to confer a selective advantage in microbial communities experiencing more frequent soil saturation and greater nitrate inputs. This study suggests metagenomics can help identify denitrification hotspots that could be protected or enhanced to treat non‐point source nitrogen pollution.
Randomized within‐subject trial to evaluate smokers’ initial perceptions, subjective effects and nicotine delivery across six vaporized nicotine products
Authors: Voos Natalie , Kaiser Lisa , Mahoney Martin C. , Bradizza Clara M. , Kozlowski Lynn T. , Benowitz Neal L. , O'Connor Richard J. , Goniewicz Maciej L.
Published: March 2019

Background and Aims

Vaporized nicotine products (VNPs) can vary in important characteristics including size, shape, flavor and nicotine yield. We examined whether complex interactions among these characteristics could affect smokers’ VNP perceptions and usage patterns.

Design

A within‐subject randomized cross‐over trial.

Setting

Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.

Participants

Eighteen daily cigarette smokers.

Measurements

Participants attended eight weekly visits during which they sampled six different VNPs (disposable, rechargeable, eGO, mod, e‐Cigar and e‐Pipe) with tobacco‐flavored e‐liquid. Prior to device use, participants completed product‐ranking questionnaires. Participants completed controlled puffing sessions during each of the six trials, after which satisfaction questionnaires were completed and blood samples were taken.

Findings

Initial perceptions showed that the smallest device (disposable) was ranked as safer compared with a larger device (e‐Pipe) (P < 0.05). Participants rated the eGO and mod devices higher on satisfaction and enjoyment from use, taste, pleasantness, harshness (‘throat hit’) and speed of effect, but lower on perceived health risk and embarrassment from use (P < 0.05). All devices had a lower Cmax than the combustible cigarette (P < 0.05), but there were differences among devices (P < 0.05). The mod, e‐Pipe and eGO provided the highest amount of perceived smoking urge relief, and this correlated strongly with Cmax across all devices (R2 = 0.8614, P = 0.007). The perceived speed of urge relief was not correlated with Tmax (R2 = 0.0035, P = 0.911)

Conclusions

Daily cigarette smokers testing six types of vaporized nicotine products (VNPs) reported that they varied in taste, amount of withdrawal relief, harshness, embarrassment from use, perceived health risk and subjective and objective nicotine delivery. The eGO and mod models have properties that may make them most effective for cigarette substitution among smokers who intend to switch to a VNP.
Medical complications associated with substance use disorders in patients with type 2 diabetes and hypertension: electronic health record findings
Authors: Winhusen Theresa , Theobald Jeff , Kaelber David C. , Lewis Daniel
Published: March 2019

Background and Aims

Screening for substance use disorder (SUD) in general medical settings may be particularly important in patients with comorbid health conditions exacerbated by SUD. This study evaluated whether SUD is associated with type 2 diabetes mellitus (T2DM) complications in patients with co‐occurring T2DM and hypertension.

Design

Analysis of a limited data set obtained through IBM Watson Health Explorys, a platform integrating data from electronic health records. Matched controls were defined for each of five SUDs: tobacco use disorder (TUD), opioid use disorder (OUD), cocaine use disorder, cannabis use disorder (CUD) and alcohol use disorder (AUD) using Mahalanobis distance within propensity score calipers.

Setting

All patients were seen in the MetroHealth System (Cleveland, OH, USA) and had diagnosis codes for T2DM and hypertension.

Participants

SUD group participants had a diagnosis of abuse/dependence for the substance of interest. Controls for each SUD group had no diagnosis code related to the SUD of interest and were selected to match the SUD patients on demographics, residential zip code median income and body mass index. Total sample sizes for each SUD–control comparison ranged from 1160 for CUD to 22 128 for TUD.

Measurements

Outcome was diagnosis (yes/no) of four T2DM complications (cerebrovascular accident, diabetic neuropathy, diabetic renal disease, myocardial infarction) and all‐cause mortality.

Findings

Logistic regressions revealed that SUD was significantly associated with greater risk of cerebrovascular accident [TUD odds ratio (OR) = 1.79, OUD‐OR = 1.94, cocaine use disorder OR = 2.67], diabetic neuropathy [TUD‐adjusted OR (aOR) = 1.47, cocaine use disorder‐aOR = 1.35, AUD‐aOR = 1.27], diabetic renal disease (TUD‐aOR = 1.25, OUD‐OR = 1.34), myocardial infarction (TUD‐OR = 1.96, OUD‐OR = 2.01, cocaine use disorder‐OR = 2.68, CUD‐OR = 2.48, AUD‐OR = 1.42) and mortality (TUD‐OR = 1.15, cocaine use disorder‐OR = 1.61, CUD‐OR = 1.49, AUD‐OR = 1.35).

Conclusions

Among patients in Ohio USA with both type 2 diabetes mellitus (T2DM) and hypertension, those with substance use disorders appear to have greater risk for T2DM complications and all‐cause mortality.
Testosterone replacement in congenital hypogonadotropic hypogonadism maintains bone density but has only limited osteoanabolic effects
Authors: Antonio L. , Caerels S. , Jardi F. , Delaunay E. , Vanderschueren D.
Published: March 2019

Background

Congenital hypogonadotropic hypogonadism (CHH) is a rare condition characterized by complete sex steroid deficiency. Therefore, CHH is a unique human model to study the impact of long‐term testosterone replacement therapy (TRT) on bone.

Objective

In this single‐center retrospective observational study, we assessed the long‐term impact of TRT on femoral and lumbar bone mineral density (BMD) in adult CHH men.

Methods

A total of 25 patients with CHH were included. Femoral and lumbar BMD was assessed by dual‐energy X‐ray absorptiometry (DEXA) and reported as T‐scores. In six patients (treatment‐naive group), BMD was measured before start of TRT. The other 19 (pre‐treated group) had received TRT for a median duration of 7 years (range 1–41 years) before first BMD measurement.

Results

Age at which TRT was started ranged from 12 to 57 years old. Median time between first and last DEXA scan was 11 years (range 2–28). At the first DEXA scan, 83% and 61% of CHH patients had lumbar and femoral osteopenia/osteoporosis, respectively. In the treatment‐naive group, the increase in lumbar T‐score was 2.19 ± 0.13 (mean ± SEM, p < 0.01 between first and last DEXA scan) and 1.47 ± 0.29 at femoral level (p < 0.001). For the pre‐treated group, the increase in lumbar and femoral T‐score was 0.77 ± 0.17 (p < 0.001) and 0.19 ± 0.12 (p = 0.13), respectively. However, lumbar and femoral osteopenia/osteoporosis persisted in 61% and 48% of CHH patients even after several years of continuous TRT. Additionally, BMD clearly decreased in patients who interrupted TRT.

Conclusion

Despite modest improvement after starting TRT, BMD remains in the osteopenic/osteoporotic range in most patients with CHH. However, prolonged TRT prevents further bone loss, both at lumbar and femoral level.
Prematurity alters skin conductance and behavioural scoring after acute stress in term‐equivalent age infants
Authors: Maillard Amelie , Garnier Elodie , Saliba Elie , Favrais Geraldine
Published: March 2019

Aim

The primary objective was to assess the effect of prematurity at term‐equivalent age on skin conductance and behavioural responses to acute stress. The secondary objective was to explore the reliability of skin conductance in detecting neonatal discomfort in preterm and full‐term populations.

Methods

Very preterm infants at term‐equivalent age and healthy full‐term neonates, 34 infants in each group, underwent the hip dysplasia screening test. The acute pain in newborn infants (APN) scale was scored before and 15, 45 and 90 seconds after stimulus. Skin conductance was measured in the 30‐second time‐lap before and after stimulus.

Results

The APN score was lower in preterm infants after intervention (term: 5.4 ± 2.8 vs. preterm: 3.9 ± 2.2; p = 0.03). Peaks‐per‐second, a skin conductance parameter, exhibited lower basal values in preterm infants than in term infants, with similar rise induced by stressful challenge. Peaks‐per‐second values were correlated to the 15‐second APN score in both groups (term: r = 0.55, p < 0.001; preterm: r = 0.43, p = 0.01).

Conclusion

Preterm birth changed skin conductance signal and behavioural response to stress at term‐equivalent age. The skin conductance device may be an objective tool for a continuous monitoring of acute neonatal stress.
Neural mechanisms of face emotion processing in youths and adults with bipolar disorder
Authors: Kryza‐Lacombe Maria , Brotman Melissa A. , Reynolds Richard C. , Towbin Kenneth , Pine Daniel S. , Leibenluft Ellen , Wiggins Jillian Lee
Published: March 2019

Objectives

Little is known about potential differences in the pathophysiology of bipolar disorder (BD) across development. The present study aimed to characterize age‐related neural mechanisms of BD.

Methods

Youths and adults with and without BD (N = 108, age range = 9.8‐55.9 years) completed an emotional face labeling task during fMRI acquisition. We leveraged three different fMRI analytic tools to identify age‐related neural mechanisms of BD, investigating (a) change in neural responses over the course of the task, (b) neural activation averaged across the entire task, and (c) amygdala functional connectivity.

Results

We found converging Age Group × Diagnosis patterns across all three analytic methods. Compared to healthy youths vs adults, youths vs adults with BD show an altered pattern in response to repeated presentation of emotional faces in medial prefrontal, amygdala, and temporoparietal regions, as well as amygdala‐temporoparietal connectivity. Specifically, medial prefrontal and lingual activation decreases over the course of repeated emotional face presentations in healthy youths vs adults but increases in youths with BD compared to adults with BD. Moreover, youths vs adults with BD show less medial prefrontal activation and amygdala‐temporoparietal junction connectivity averaged over the task, but this difference is not found for healthy youths vs adults.

Conclusion

Although longitudinal confirmation and replication will be necessary, these findings suggest that neural development may be aberrant in BD and that some neural mechanisms mediating BD may differ in adults vs children with the illness.