bluuebunny/crossref_metadata_2025 huggingface dataset:
Mycorrhizal specificity does not limit the distribution of an endangered orchid species
Authors: Waud Michael , Brys Rein , Van Landuyt Wouter , Lievens Bart , Jacquemyn Hans
Published: January 2017

What factors determine the distribution of a species is a central question in ecology and conservation biology. In general, the distribution of plant species is assumed to be controlled by dispersal or environmentally controlled recruitment. For plant species which are critically dependent on mycorrhizal symbionts for germination and seedling establishment, specificity in mycorrhizal associations and availability of suitable mycorrhizal fungi can be expected to have a major impact on successful colonization and establishment and thus ultimately on a species distribution. We combined seed germination experiments with soil analyses and fungal assessments using 454 amplicon pyrosequencing to test the relative importance of dispersal limitation, mycorrhizal availability and local growth conditions on the distribution of the orchid speciesLiparis loeselii, which, despite being widely distributed, is rare and endangered in Europe. We compared local soil conditions, seed germination and mycorrhizal availability in the soil between locations in northern Belgium and France whereL. loeseliioccurs naturally and locations where conditions appear suitable, but where adults of the species are absent. Our results indicated that mycorrhizal communities associating withL. loeseliivaried among sites and plant life cycle stages, but the observed variations did not affect seed germination, which occurred regardless of currentL. loeseliipresence and was significantly affected by soil moisture content. These results indicate thatL. loeseliiis a mycorrhizal generalist capable of opportunistically associating with a variety of fungal partners to induce seed germination. They also indicate that availability of fungal associates is not necessarily the determining factor driving the distribution of mycorrhizal plant species.
The population genomic signature of environmental association and gene flow in an ecologically divergent tree speciesMetrosideros polymorpha(Myrtaceae)
Authors: Izuno Ayako , Kitayama Kanehiro , Onoda Yusuke , Tsujii Yuki , Hatakeyama Masaomi , Nagano Atsushi J. , Honjo Mie N. , Shimizu‐Inatsugi Rie , Kudoh Hiroshi , Shimizu Kentaro K. , Isagi Yuji
Published: January 2017

Genomewide markers enable us to study genetic differentiation within a species and the factors underlying it at a much higher resolution than before, which advances our understanding of adaptation in organisms. We investigated genomic divergence inMetrosideros polymorpha, a woody species that occupies a wide range of ecological habitats across the Hawaiian Islands and shows remarkable phenotypic variation. Using 1659 single nucleotide polymorphism (SNP) markers annotated with the genome assembly, we examined the population genetic structure and demographic history of nine populations across five elevations and two ages of substrates on Mauna Loa, the island of Hawaii. The nine populations were differentiated into two genetic clusters distributed on the lower and higher elevations and were largely admixed on the middle elevation. Demographic modelling revealed that the two genetic clusters have been maintained in the face of gene flow, and the effective population size of the high‐altitude cluster was much smaller. AFST‐based outlier search among the 1659SNPs revealed that 34SNPs (2.05%) were likely to be under divergent selection and the allele frequencies of 21 of them were associated with environmental changes along elevations, such as temperature and precipitation. This study shows a genomic mosaic ofM. polymorpha, in which contrasting divergence patterns were found. While most genomic polymorphisms were shared among populations, a small fraction of the genome was significantly differentiated between populations in diverse environments and could be responsible for the dramatic adaptation to a wide range of environments.
The genetic architecture of defence as resistance to and tolerance of bacterial infection in Drosophila melanogaster
Authors: Howick Virginia M. , Lazzaro Brian P.
Published: January 2017

Defence against pathogenic infection can take two forms: resistance and tolerance. Resistance is the ability of the host to limit a pathogen burden, whereas tolerance is the ability to limit the negative consequences of infection at a given level of infection intensity. Evolutionarily, a tolerance strategy that is independent of resistance could allow the host to avoid mounting a costly immune response and, theoretically, to avoid a co‐evolutionary arms race between pathogen virulence and host resistance. Biomedically, understanding the mechanisms of tolerance and how they relate to resistance could potentially yield treatment strategies that focus on health improvement instead of pathogen elimination. To understand the impact of tolerance on host defence and identify genetic variants that determine host tolerance, we defined genetic variation in tolerance as the residual deviation from a binomial regression of fitness under infection against infection intensity. We then performed a genomewide association study to map the genetic basis of variation in resistance to and tolerance of infection by the bacterium Providencia rettgeri. We found a positive genetic correlation between resistance and tolerance, and we demonstrated that the level of resistance is highly predictive of tolerance. We identified 30 loci that predict tolerance, many of which are in genes involved in the regulation of immunity and metabolism. We used RNAi to confirm that a subset of mapped genes have a role in defence, including putative wound repair genes grainy head and debris buster. Our results indicate that tolerance is not an independent strategy from resistance, but that defence arises from a collection of physiological processes intertwined with canonical immunity and resistance.
Investigating the extent of parallelism in morphological and genomic divergence among lake trout ecotypes in Lake Superior
Authors: Perreault‐Payette Alysse , Muir Andrew M. , Goetz Frederick , Perrier Charles , Normandeau Eric , Sirois Pascal , Bernatchez Louis
Published: January 2017

Understanding the emergence of species through the process of ecological speciation is a central question in evolutionary biology which also has implications for conservation and management. Lake trout (Salvelinus namaycush) is renowned for the occurrence of different ecotypes linked to resource and habitat use throughout North America. We aimed to unravel the fine genetic structure of the four lake trout ecotypes in Lake Superior. A total of 486 individuals from four sites were genotyped at 6822 filtered SNPs using RADseq technology. Our results revealed different extent of morphological and genetic differentiation within the different sites. Overall, genetic differentiation was weak but significant and was on average three times higher between sites (mean FST = 0.016) than between ecotypes within sites (mean FST = 0.005) indicating higher level of gene flow or a more recent shared ancestor between ecotypes within each site than between populations of the same ecotype. Evidence of divergent selection was also found between ecotypes and/or in association with morphological variation. Outlier loci found in genes related to lipid metabolism and visual acuity were of particular interest in this context of ecotypic divergence. However, we did not find clear indication of parallelism at the genomic level, despite the presence of phenotypic parallelism among some ecotypes from different sampling sites. Overall, the occurrence of different levels of both genomic and phenotypic differentiation between ecotypes within each site with several differentiated loci linked to relevant biological functions supports the presence of a continuum of divergence in lake trout.
Comparison of green and albino individuals of the partially mycoheterotrophic orchid Epipactis helleborine on molecular identities of mycorrhizal fungi, nutritional modes and gene expression in mycorrhizal roots
Authors: Suetsugu Kenji , Yamato Masahide , Miura Chihiro , Yamaguchi Katsushi , Takahashi Kazuya , Ida Yoshiko , Shigenobu Shuji , Kaminaka Hironori
Published: January 2017

Some green orchids obtain carbon from their mycorrhizal fungi, as well as from photosynthesis. These partially mycoheterotrophic orchids sometimes produce fully achlorophyllous, leaf‐bearing (albino) variants. Comparing green and albino individuals of these orchids will help to uncover the molecular mechanisms associated with mycoheterotrophy. We compared green and albino Epipactis helleborine by molecular barcoding of mycorrhizal fungi, nutrient sources based on 15N and 13C abundances and gene expression in their mycorrhizae by RNA‐seq and cDNA de novo assembly. Molecular identification of mycorrhizal fungi showed that green and albino E. helleborine harboured similar mycobionts, mainly Wilcoxina. Stable isotope analyses indicated that albino E. helleborine plants were fully mycoheterotrophic, whereas green individuals were partially mycoheterotrophic. Gene expression analyses showed that genes involved in antioxidant metabolism were upregulated in the albino variants, which indicates that these plants experience greater oxidative stress than the green variants, possibly due to a more frequent lysis of intracellular pelotons. It was also found that some genes involved in the transport of some metabolites, including carbon sources from plant to fungus, are higher in albino than in green variants. This result may indicate a bidirectional carbon flow even in the mycoheterotrophic symbiosis. The genes related to mycorrhizal symbiosis in autotrophic orchids and arbuscular mycorrhizal plants were also upregulated in the albino variants, indicating the existence of common molecular mechanisms among the different mycorrhizal types.
Purging putative siblings from population genetic data sets: a cautionary view
Authors: Waples Robin S. , Anderson Eric C.
Published: January 2017

Interest has surged recently in removing siblings from population genetic data sets before conducting downstream analyses. However, even if the pedigree is inferred correctly, this has the potential to do more harm than good. We used computer simulations and empirical samples of coho salmon to evaluate strategies for adjusting samples to account for family structure. We compared performance in full samples and sibling‐reduced samples of estimators of allele frequency (), population differentiation () and effective population size (). Results: (i) unless simulated samples included large family groups together with a component of unrelated individuals, removing siblings generally reduced precision of and ; (ii) based on the linkage disequilibrium method was largely unbiased using full random samples but became increasingly upwardly biased under aggressive purging of siblings. Under nonrandom sampling (some families over‐represented), using full samples was downwardly biased; removing just the right ‘Goldilocks’ fraction of siblings could produce an unbiased estimate, but this sweet spot varied widely among scenarios; (iii) weighting individuals based on the inferred pedigree (to produce a best linear unbiased estimator, BLUE) maximized precision of when the inferred pedigree was correct but performed poorly when the pedigree was wrong; (iv) a variant of sibling removal that leaves intact small sibling groups appears to be more robust to errors in inferences about family structure. Our results illustrate the complex challenges posed by presence of family structure, suggest that no single optimal solution exists and argue for caution in adjusting population genetic data sets for the presence of putative siblings without fully understanding the consequences.
Cryptic lineages of a common alpine mayfly show strong life‐history divergence
Authors: Leys Marie , Keller Irene , Robinson Christopher T. , Räsänen Katja
Published: January 2017

Understanding ecological divergence of morphologically similar but genetically distinct species – previously considered as a single morphospecies – is of key importance in evolutionary ecology and conservation biology. Despite their morphological similarity, cryptic species may have evolved distinct adaptations. If such ecological divergence is unaccounted for, any predictions about their responses to environmental change and biodiversity loss may be biased. We used spatio‐temporally replicated field surveys of larval cohort structure and population genetic analyses (using nuclear microsatellite markers) to test for life‐history divergence between two cryptic lineages of the alpine mayfly Baetis alpinus in the Swiss Alps. We found that the more widespread and abundant cryptic lineage represents a ‘generalist’ with at least two cohorts per year, whereas the less abundant lineage is restricted to higher elevations and represents a ‘specialist’ with a single cohort per year. Importantly, our results indicate partial temporal segregation in reproductive periods between these lineages, potentially facilitating local coexistence and reproductive isolation. Taken together, our findings emphasize the need for a taxonomic revision: widespread and apparently generalist morphospecies can hide cryptic lineages with much narrower ecological niches and distribution ranges.
Unphosphorylated EIIANtr induces ClpAP‐mediated degradation of RpoS in Azotobacter vinelandii
Authors: Muriel‐Millán Luis Felipe , Moreno Soledad , Gallegos‐Monterrosa Ramsés , Espín Guadalupe
Published: January 2017

The nitrogen‐related phosphotransferase system (PTSNtr) is composed of the EINtr, NPr and EIIANtr proteins that form a phosphorylation cascade from phosphoenolpyruvate. PTSNtr is a global regulatory system present in most Gram‐negative bacteria that controls some pivotal processes such as potassium and phosphate homeostasis, virulence, nitrogen fixation and ABC transport activation. In the soil bacterium Azotobacter vinelandii, unphosphorylated EIIANtr negatively regulates the expression of genes related to the synthesis of the bioplastic polyester poly‐β‐hydroxybutyrate (PHB) and cyst‐specific lipids alkylresorcinols (ARs). The mechanism by which EIIANtr controls gene expression in A. vinelandii is not known. Here, we show that, in presence of unphosphorylated EIIANtr, the stability of the stationary phase sigma factor RpoS, which is necessary for transcriptional activation of PHB and ARs synthesis related genes, is reduced, and that the inactivation of genes coding for ClpAP protease complex in strains that carry unphosphorylated EIIANtr, restored the levels and in vivo stability of RpoS, as well as the synthesis of PHB and ARs. Taken together, our results reveal a novel mechanism, by which EIIANtr globally controls gene expression in A. vinelandii, where the unphosphorylated EIIANtr induces the degradation of RpoS by the proteolytic complex ClpAP.
c‐di‐AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation
Authors: Whiteley Aaron T. , Garelis Nicholas E. , Peterson Bret N. , Choi Philip H. , Tong Liang , Woodward Joshua J. , Portnoy Daniel A.
Published: January 2017

Cyclic diadenosine monophosphate (c‐di‐AMP) is a conserved nucleotide second messenger critical for bacterial growth and resistance to cell wall‐active antibiotics. In Listeria monocytogenes, the sole diadenylate cyclase, DacA, is essential in rich, but not synthetic media and ΔdacA mutants are highly sensitive to the β‐lactam antibiotic cefuroxime. In this study, loss of function mutations in the oligopeptide importer (oppABCDF) and glycine betaine importer (gbuABC) allowed ΔdacA mutants to grow in rich medium. Since oligopeptides were sufficient to inhibit growth of the ΔdacA mutant we hypothesized that oligopeptides act as osmolytes, similar to glycine betaine, to disrupt intracellular osmotic pressure. Supplementation with salt stabilized the ΔdacA mutant in rich medium and restored cefuroxime resistance. Additional suppressor mutations in the acetyl‐CoA binding site of pyruvate carboxylase (PycA) rescued cefuroxime resistance and resulted in a 100‐fold increase in virulence of the ΔdacA mutant. PycA is inhibited by c‐di‐AMP and these mutations prompted us to examine the role of TCA cycle enzymes. Inactivation of citrate synthase, but not down‐stream enzymes suppressed ΔdacA phenotypes. These data suggested that c‐di‐AMP modulates central metabolism at the pyruvate node to moderate citrate production and indeed, the ΔdacA mutant accumulated six times the concentration of citrate present in wild‐type bacteria.
Buffering Against the Detrimental Effects of Demographic Faultlines: The Curious Case of Intragroup Conflict in Small Work Groups
Authors: Adair Wendi L. , Liang Lindie H. , Hideg Ivona
Published: January 2017

Group faultline literature suggests that subgroups impede group functioning. We propose that team conflict may buffer the detrimental effects of faultlines on group performance. We draw on social categorization and group process theories suggesting that the negative effects of fault‐lines are due to increased competition and decreased communication across subgroups and can be diminished with cross‐subgroup information exchange and elaboration. We propose that intragroup conflict in small groups will decrease negative effects of demographic faultlines because detecting conflict and engaging in conflict management require cross‐subgroup communication and information elaboration. In Study 1, using student groups we found that relationship, task, and process conflict buffered the negative effect of demographic faultline strength on group performance. In Study 2, we manipulated conflict and group faultlines (ethnic faultlines vs. no faultlines) and found that group conflict buffered the negative effect of faultlines on group performance. Theoretical contributions and practical implications are discussed.
Do I Trust You? Depends on What You Feel: Interpersonal Effects of Emotions on Initial Trust at Zero‐Acquaintance
Authors: Belkin Liuba Y. , Rothman Naomi B.
Published: January 2017

This article explores the interpersonal effects of emotions on stereotype formation and initial trust in zero‐acquaintance interactions. In three experiments, we demonstrate that perceptions of partner sociability, morality, and competence are significantly influenced by emotional expressions and are important predictors of trust. Specifically, we show that in zero‐acquaintance interactions, displays of happiness increase, but displays of anger decrease stereotypes of sociability, morality, and competence. Happiness expressions are also conducive to trust, whereas expressions of anger are detrimental to trust. We further demonstrate that expressions of ambivalence do not affect perceptions of sociability, but decrease perceptions of morality and competence. Overall, expressions of ambivalence have a negative effect on partner trust. Perceptions of morality consistently explain the effect of expressed happiness, anger, and ambivalence on initial trust across the three experiments and different bargaining contexts. Implications for research on emotions and trust in negotiations are discussed.
Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root‐external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters
Authors: Sawers Ruairidh J. H. , Svane Simon F. , Quan Clement , Grønlund Mette , Wozniak Barbara , Gebreselassie Mesfin‐Nigussie , González‐Muñoz Eliécer , Chávez Montes Ricardo A. , Baxter Ivan , Goudet Jerome , Jakobsen Iver , Paszkowski Uta
Published: January 2017

Plant interactions with arbuscular mycorrhizal fungi have long attracted interest for their potential to promote more efficient use of mineral resources in agriculture. Their use, however, remains limited by a lack of understanding of the processes that determine the outcome of the symbiosis. In this study, the impact of host genotype on growth response to mycorrhizal inoculation was investigated in a panel of diverse maize lines.

A panel of 30 maize lines was evaluated with and without inoculation with arbuscular mycorrhizal fungi. The line Oh43 was identified to show superior response and, along with five other reference lines, was characterized in greater detail in a split‐compartment system, using 33P to quantify mycorrhizal phosphorus uptake.

Changes in relative growth indicated variation in host capacity to profit from the symbiosis. Shoot phosphate content, abundance of root‐internal and ‐external fungal structures, mycorrhizal phosphorus uptake, and accumulation of transcripts encoding plant PHT1 family phosphate transporters varied among lines.

Superior response in Oh43 is correlated with extensive development of root‐external hyphae, accumulation of specific Pht1 transcripts and high phosphorus uptake by mycorrhizal plants. The data indicate that host genetic factors influence fungal growth strategy with an impact on plant performance.
When and why does sex chromosome dosage compensation evolve?
Authors: Chandler Christopher H.
Published: January 2017

In many species, sex is determined by sex chromosomes, and the sex‐specific chromosome (Y or W) stops recombining until it degenerates and carries fewer genes than its recombining counterpart (X or Z). This creates an imbalance in the dosage of most sex‐linked genes between males and females. Early work in model organisms demonstrated that X chromosomes in multiple groups independently evolved regulatory mechanisms maintaining balanced expression of X‐linked genes. However, recent studies have shown that these dosage compensation mechanisms are far from universal. It remains unclear why dosage compensation mechanisms evolved in some groups of organisms and not others. Two factors have led to confusion in this area: first, different authors sometimes define dosage compensation in different ways; second, dosage compensation is sometimes viewed as an all‐or‐nothing phenomenon, even though it may vary across cell types, developmental stages, and different classes of genes. Here, I discuss current approaches to testing for sex chromosome dosage compensation and highlight patterns in the phylogenetic distribution of dosage compensation mechanisms and possible explanations for those patterns. I conclude by outlining how the presence of dosage compensation can be tested in nearly any nonmodel organism and provide some recommendations for future studies.
Junctional Ectopic Tachycardia Localization and Procedural Approach using Cryoablation
Authors: PIERICK ALYSON R. , LAW IAN H. , MULDONADO JENNIFER R. , VON BERGEN NICHOLAS H.
Published: January 2017

Background

Idiopathic junctional ectopic tachycardia (JET) may still be difficult to control with antiarrhythmic therapy. Transcatheter ablation can be challenging and may be associated with a high risk of unintended atrioventricular block. The objective of this manuscript is to report the procedural technique, the location of the successful ablation, and the procedural characteristics while utilizing 3D mapping for cryoablation of JET.

Methods

A retrospective analysis was performed on all patients who had undergone cryothermal ablation for the treatment of JET at a single center. Patient, arrhythmia, and procedural information and long‐term outcomes were evaluated.

Results

Thirteen patients with JET were treated by cryothermal ablation. The JET arrhythmia burden varied greatly, generally with inadequate control on medications. Left ventricular dilation was present in three patients, and one patient had dilated cardiomyopathy. The median age at the time of procedure was 13 years, with median weight of 54.1 kg. The ectopic focus was ablated in 11/13 patients within the lower 2/3 of the triangle of Koch (TOK) with cryotherapy. Ablations, which were not successful, low in the TOK were associated with substantially longer procedures, and had a higher risk of recurrence. There was late resolution of the arrhythmia in two of three acutely unsuccessful ablations. There were no complications.

Conclusion

In the majority of patients JET can be safely ablated with the use of cryotherapy. Foci not identified in the lower 2/3 of the TOK are associated with longer procedures, more lesions, and decreased chance for long‐term success.
Dermatomal spread following posterior transversus abdominis plane block in pediatric patients: our initial experience
Authors: Hernandez Maria A. , Vecchione Tricia , Boretsky Karen
Published: January 2017

Introduction

Several techniques for the transversus abdominis plane (TAP) block have been described. The extent of sensory changes using an ultrasound‐guided posterior TAP block (pTAP) remains unclear in pediatric patients. The primary aim of this study was to report the extent of sensory changes achieved with pTAP; specifically the highest thoracic dermatome anesthetized. Secondary outcomes were pain scores (PS), opioid consumption, and complications.

Methods

We retrospectively reviewed the medical records of patients less than 21 years of age undergoing abdominal surgery with a unilateral or bilateral pTAP(s) for postoperative analgesia. The local anesthetic was placed posterior to the termination of the transversus abdominis muscle where the thoracolumbar fascia overrides the quadratus lumborum muscle. The extent of sensory changes, pain scores, and opioid consumption were analyzed.

Results

A total of 10 patients (15 pTAP blocks) met the inclusion criteria. The mean (sd; range) age and weight were 15 years (5 years; range 7–20 years) and 57 kg (21 kg; 27–97 kg), respectively. The cephalad dermatome levels achieved were: T7 in 6/15 (40%); T8 in 10/15 (67%); and T9 in 14/15 (93%). An inferior dermatome level of T12/L1 and sensory extension from midaxillary line to the midline was documented in 15/15 blocks. The mean intraoperative and postanesthesia care unit (PACU) opioid consumption in morphine equivalents were 0.34 mg·kg−1 (sd = 0.12 mg·kg−1) and 0.04 mg·kg−1 (sd = 0.05 mg·kg−1), respectively. PACU pain scores were mild (<4) in 60%, moderate (4–7) in 30%, and severe (>7) in 10% of patients. No complications were reported.

Discussion

The current uncertainty regarding sensory blockade limits the clinical application of TAP blocks. While the midaxillary approach results in unpredictable sensory changes of the abdomen, we reliably achieved sensory changes up to a T9 level in 93% of the blocks.

Conclusion

In this small series of patients, we demonstrate a high technical success rate of achieving cutaneous analgesia to the abdominal wall. These results should encourage clinical studies of the efficacy of this block for abdominal surgery in pediatric patients.
Delivery of anesthesia for children with Mucopolysaccharidosis Type III (Sanfilippo syndrome): a review of 86 anesthetics
Authors: Cohen Marc A. , Stuart Grant M.
Published: January 2017

Background

Sanfilippo syndrome (MPS III) is rare, with 97 cases in the United Kingdom between 1988 and 1998. Mucopolysaccharide infiltration of tissues in mucopolysaccharidosis (MPS) causes multi‐systemic pathology including difficult airways and cardiac disease. Published anesthesia case reviews of Sanfilippo syndrome have included limited numbers of patients to date.

Aim

To identify the perioperative management and complications of anesthesia in children with mucopolysaccharidosis Type III at Great Ormond Street Hospital.

Methods

A retrospective case note review of all children with MPS III in our institution was undertaken. All medical notes and anesthetic charts were analyzed, and conduct of anesthesia, airway management, perioperative complications, and associated comorbidities were identified.

Results

There were 43 patients with MPS III, of which 34 required anesthesia, on 86 occasions for 156 procedures between 1993 and 2015. Dental extraction was the likeliest indication for anesthesia (34%) (general surgery [30%]; ear, nose, and throat [26%]; other [10%]). Thirteen of 34 patients had cardiac pathology (valvular [n = 6], functional [n = 6], electrophysiological [n = 1]). Ten of 34 patients had evidence of clotting abnormality (mild prolonged clotting time [n = 5], low von Willebrand factor [n = 2], thrombocytopenia [n = 3]). The majority of intubations were Cormack–Lehane Grade 1 (n = 47) (Grade 2 [n = 14], Grade 3 [n = 1], Grade 4 [n = 1]). In 86 anesthetics, there were 0 cases of difficulty with mask ventilation. There was 1 case of failed intubation. They were subsequently anesthetized by a different operator uneventfully at a later date. Two perioperative complications occurred: a failed intubation and bleeding during adenoidectomy.

Conclusion

We demonstrate a difficult airway is unlikely when anesthetizing an MPS III patient although a risk does remain. A significant proportion of MPS III have cardiac involvement although no perioperative complications were described. With associated coagulation issues, bleeding tendency, while uncommon, can occur in this group.
Ectopic expression of two AREB/ABF orthologs increases drought tolerance in cotton (Gossypium hirsutum)
Authors: Kerr Tyson C. C. , Abdel‐Mageed Haggag , Aleman Lorenzo , Lee Joohyun , Payton Paxton , Cryer Dakota , Allen Randy D.
Published: January 2017

Plants have evolved complex molecular, cellular and physiological mechanisms to respond to environmental stressors. Because of the inherent complexity of this response, genetic manipulation to substantially improve water deficit tolerance, particularly in agricultural crops, has been largely unsuccessful, as the improvements are frequently accompanied by slower growth and delayed reproduction. Here, we ectopically express two abiotic stress‐responsive bZIP AREB/ABF transcription factor orthologs, Arabidopsis ABF3 and Gossypium hirsutum ABF2D, in G. hirsutum, to compare the effects of exogenous and endogenous AREB/ABF transgene overexpression on dehydration resilience. Our results show that ectopic expression of each of these orthologs increases dehydration resilience, although these increases are accompanied by slower growth. These phenotypic effects are proportional to the ectopic expression level in the GhABF2D transgenic plants, while the phenotypes of all of the AtABF3 transgenic plants are similar, largely independent of ectopic expression level, possibly indicating differential post‐transcriptional regulation of these transgenes. Our results indicate that overexpression of exogenous and endogenous ABF homologs in G. hirsutum substantially increases drought resilience, primarily through stomatal regulation, negatively impacting transpiration and photosynthetic productivity.
Genomic analysis and clinical management of adolescent cutaneous melanoma
Authors: Rabbie Roy , Rashid Mamunur , Arance Ana M. , Sánchez Marcelo , Tell‐Marti Gemma , Potrony Miriam , Conill Carles , van Doorn Remco , Dentro Stefan , Gruis Nelleke A. , Corrie Pippa , Iyer Vivek , Robles‐Espinoza Carla Daniela , Puig‐Butille Joan A. , Puig Susana , Adams David J.
Published: January 2017

Melanoma in young children is rare; however, its incidence in adolescents and young adults is rising. We describe the clinical course of a 15‐year‐old female diagnosed with AJCC stage IB non‐ulcerated primary melanoma, who died from metastatic disease 4 years after diagnosis despite three lines of modern systemic therapy. We also present the complete genomic profile of her tumour and compare this to a further series of 13 adolescent melanomas and 275 adult cutaneous melanomas. A somatic BRAFV600E mutation and a high mutational load equivalent to that found in adult melanoma and composed primarily of C>T mutations were observed. A germline genomic analysis alongside a series of 23 children and adolescents with melanoma revealed no mutations in known germline melanoma‐predisposing genes. Adolescent melanomas appear to have genomes that are as complex as those arising in adulthood and their clinical course can, as with adults, be unpredictable.
Factors affecting the virulence of Ralstonia solanacearum and its colonization on tobacco roots
Authors: Li X. , Liu Y. , Cai L. , Zhang H. , Shi J. , Yuan Y.
Published: January 2017

Tobacco bacterial wilt caused by Ralstonia solanacearum is a serious disease affecting tobacco cultivation in southwest China. The response surface methodology was employed to evaluate the optimal conditions of tobacco bacterial wilt, and green fluorescent protein gene (gfp) labelling was applied to monitor the location and survival dynamics of R. solanacearum (Rs::gfp) on tobacco roots and in soil under these optimal conditions. The results showed that the highest wilt incidence was 91.13%, which occurred when the population reached 6.6 × 106 CFU/g soil, the temperature was 30.55 °C, and the humidity was >81.42%. The Rs::gfp densely colonized the root tips and root hairs, and cells of Rs::gfp were observed intermittently in the elongation zone or at the point of the emerging lateral roots. The Rs::gfp number in the rhizosphere soil was 10.75‐, 73.13‐ and 74.86‐times higher than that in the bulk soil at 10, 15 and 20 days after transplantation, respectively. Increased colonization by Rs::gfp was related to the population of the pathogen, the environmental temperature and the humidity in the soil. These three conditions determined whether R. solanacearum would induce tobacco wilt. This is the first study to investigate factors affecting the virulence of a tobacco wilt bacterial pathogen, which is important for conducting field diagnosis and biocontrol of tobacco bacterial wilt.
The elicitation of steady‐state visual evoked potentials during sleep
Authors: Norton James J. S. , Umunna Stephen , Bretl Timothy
Published: January 2017

This study confirmed the hypothesis that it is possible to elicit SSVEPs through closed eyelids during NREM sleep. To test this hypothesis, SSVEP amplitudes were measured in eight subjects across two conditions of stimulation (stimulation on and stimulation off) and three brain states (waking, light sleep, and deep sleep). Results showed a significant interaction between stimulation and brain state. In particular, EEG activity at the frequency of stimulation was higher during both light sleep and deep sleep in the stimulation on condition than in the stimulation off condition. The fact that it is possible to elicit SSVEPs during sleep may provide a new way to study how SSVEPs are generated in the brain—one that might help resolve open questions such as identifying the SSVEP activation sequence or deciding if SSVEPs derive from evoked or oscillatory neural processes.
Legal Principles in Antitrust Enforcement
Authors: Houba Harold , Motchenkova Evgenia , Wen Quan
Published: January 2017

We study antitrust enforcement that aims to channel price‐fixing incentives of cartels through setting fine schedules and detection levels. Fines obey legal principles, such as the punishment should fit the crime, proportionality, bankruptcy considerations, and minimum fines. Bankruptcy considerations limit maximum fines, ensure abnormal cartel profits, and impose a challenge for optimal antitrust enforcement. We derive the fine schedule and detection level that are constrained‐optimal under legal principles and sustainability of cartel prices. This fine schedule lies below the maximum fine, makes collusion on lower prices more attractive than on higher prices, and, hence, relates to the body of literature on marginal deterrence.
How Effective Are Non‐Monetary Instruments for Safe Driving? Panel Data Evidence on the Effect of the Demerit Point System in Denmark
Authors: Abay Kibrom A.
Published: January 2017

Using unusually rich longitudinal data on traffic offenses, this paper exploits a reform that introduced a point‐recording scheme in Denmark to estimate the behavioral responses of drivers to a non‐monetary penalty based on demerit points. We find that drivers exhibited substantial behavioral responses to each demerit point assigned to their driving licenses. We also find that drivers’ efforts, and hence responses, increased with the number of demerit points they accumulated. Depending on the number of demerit points accumulated, drivers with one or more demerit points reduced their frequency of traffic offenses by 9–34 percent.
Marriage Delay, Time to Play? Marital Horizons and Hooking Up in College
Authors: Allison Rachel , Risman Barbara J.
Published: January 2017

Previous research suggests that an increasing age at first marriage has contributed to the prevalence of sexual hookups on U.S. college campuses. In this article, we use life course and marital horizons theories to analyze the influence of ideal age at first marriage on hooking up among unmarried heterosexual college students. Analyses of the Online College Social Life Survey (N = 17,981) show a positive association between ideal age at first marriage and hookups for most students, but not for students whose mothers have no post‐secondary education, Asian men, Asian women, and Latina women. Variation in ideal marriage timing does not account for gender, racial/ethnic, and class gaps in hookup participation. Results are discussed with reference to the role of sexuality in processes of stratification throughout young adulthood.
Pseudozyma and other non‐Candida opportunistic yeast bloodstream infections in a large stem cell transplant center
Authors: Pande Anupam , Non Lemuel R. , Romee Rizwan , Santos Carlos A. Q.
Published: January 2017

Non‐Candida opportunistic yeasts are emerging causes of bloodstream infection (BSI) in immunocompromised hosts. However, their clinical presentation, management, and outcomes in stem cell transplant (SCT) recipients are not well described. We report the first case to our knowledge of Pseudozyma BSI in a SCT recipient. He had evidence of cutaneous involvement, which has not been previously described in the literature. He became infected while neutropenic and receiving empiric micafungin, which is notable because Pseudozyma is reported to be resistant to echinocandins. He was successfully treated with the sequential use of liposomal amphotericin B and voriconazole. A review of the literature revealed nine reported instances of Pseudozyma fungemia. We performed a retrospective review of 3557 SCT recipients at our institution from January 2000 to June 2015 and identified four additional cases of non‐Candida yeast BSIs. These include two with Cryptococcus, one with Trichosporon, and one with Saccharomyces. Pseudozyma and other non‐Candida yeasts are emerging pathogens that can cause severe and disseminated infections in SCT recipients and other immunocompromised hosts. Clinicians should have a high degree of suspicion for echinocandin‐resistant yeasts, if patients develop breakthrough yeast BSIs while receiving echinocandin therapy.
Validation of a smartphone‐based point‐of‐care hemoglobin assay for use in dogs
Authors: Farrell Kate S. , Chapman Phillip L. , Sullivan Lauren A.
Published: January 2017

Objective

To validate a smartphone‐based spectrophotometric assay for point‐of‐care (POC) measurement of hemoglobin (Hgb) concentration against the standard measurement method in dogs without increases in serum lipemia, hemolysis, or bilirubin.

Design

Prospective observational study.

Setting

University teaching hospital.

Animals

One hundred thirty‐nine dogs that had a CBC and corresponding biochemical profile submitted to the clinical pathology laboratory.

Interventions

None.

Measurements and Main Results

Blood tubes submitted for CBC were collected for hemoglobin (Hgb) measurements performed on a POC smartphone device. Each whole blood sample was run on the smartphone in duplicate using 2 strips, for a total of 4 POC Hgb readings per dog. Data collected for each dog included CBC Hgb value, 4 POC Hgb values, and select biochemistry values (bilirubin, lipemia, hemolysis, icterus). A calibration equation was estimated using a weighted linear regression: estimated CBC = (avgPOC–0.4871)/1.0015. For each dog, the percent error was computed between estimated and actual Hgb values; 95% of the percent errors ranged from –13.2% to 20.1%. The standard deviation of percent errors was 7.9% overall. When samples were further divided according to CBC Hgb concentration (low, normal or high), the standard deviation of percent error was 6.7% when Hgb<13 g/dL [130 g/L], 8.9% when Hgb 13–20 g/dL [130–200 g/L], and 6.5% when Hgb>20 g/dL [200 g/L]. The coefficient of variability among the 4 individual POC readings was 3.4%.

Conclusions

A smartphone‐based photometric method for measuring Hgb represents a clinically useful POC alternative to a standard laboratory Hgb measurement. There was excellent intrasample reproducibility, and the standard deviation of percent errors was relatively constant across CBC ranges. Additional sampling of patients with a greater range of diseases and biochemical abnormalities that may influence spectrophotometric assays (ie, abnormal bilirubin, icterus, lipemia, hemolysis) is warranted to extend the findings of this study.
Partial removal and detoxification of Malachite Green and Crystal Violet from laboratory artificially contaminated water by Pleurotus ostreatus
Authors: Morales-Álvarez Edwin David , Rivera-Hoyos Claudia Marcela , González-Ogliastri Natalia , Rodríguez-Vázquez Refugio , Poutou-Piñales Raúl Alberto , Daza Carlos Enrique , Pedroza Rodriguez Aura Marina
Published: January 2017

The triphenylmethane dyes Malachite Green (MG) and Crystal Violet (CV) are cationic dyes and mix with domestic wastewater when dumped; increasing, among others, the chemical and biological demand of oxygen and can cause acute toxicity at different trophic levels. Promoting the removal (decolorization) of MG and CV, and laccase activity (54.8 ± 8.9 and 30.6 ± 2.9 UL-1 respectively) by using P. ostreatus viable biomass needed parameters such as pH (4.5 and 6.0), temperature (25 to 30 °C), stirring speed (120 rpm), percentage of inoculum (2% v/v), and dye concentration (20 and 10 mg L-1). In adsorption studies, it was showed that an acidic pH favors the adsorption of both dyes and the model of pseudo-second order describes best the phenomenon of adsorption. Finally, the germination index (GI), using Lactuca sativa seeds for the initial dyes solutions, was <50%; demonstrating its high phytotoxic effect. When dye solutions were treated with viable biomass, the GI increased, leaving open the possibility to performing future research to determine if the aqueous solutions, post-treated with P. ostreatus, could be used in treatments that generate less toxic water which could be used in processes that do not require potable water.
Impact of oxygen plasma on nitrided and annealed atomic layer deposited SiO2/high-k/metal gate for high-voltage input and output fin-shaped field effect transistor devices
Authors: Siddiqui Shahab , Dai Min , Loesing Rainer , Kaltalioglu Erdem , Pandey Rajan , Sathiyanarayanan Rajesh , De Sandip , Raghavan Srini , Parks Harold
Published: January 2017

In this study, the authors investigate the impact of radical oxygen plasma on nitrided and annealed atomic layer deposited (ALD) SiO2 as a thick gate oxide (1.65–3 V) with a high-k/metal gate transistor. Time-dependent-dielectric-breakdown voltage, secondary ion mass spectroscopy (SIMS), and x-ray photoelectron spectroscopy (XPS) studies were conducted, and the results are discussed for nitrided and annealed ALD SiO2 with and without radical oxygen plasma exposure. Atomistic material simulations were performed to understand the reactions between oxygen radicals and silicon oxynitride (SiON). Our key findings from SIMS and XPS show that radical oxygen plasma exposure led to a 34% nitrogen loss from the thick SiON gate oxide and damaged the gate oxide, resulting in a 1 V reduction in the dielectric breakdown voltage. Atomistic material simulation results also show that atomic oxygen can react with Si-(ON)-Si to form Si–O–Si bonds and mobilize NO into the interstitial space. Similarly, when O atoms and O2 molecules are placed near N clusters, spontaneous diffusion of N2 into the interstitial space occurs. Diffusion barrier calculations further indicate a barrier energy of less than 0.5 eV in SiO2 and SiON, which can lead to the out-diffusion of NO and N2 from SiO2 and SiON. These compositional changes may result in increased leakage and a degraded breakdown voltage. The increased gate leakage and degraded breakdown voltage is attributed to the compositional changes in SiON.
A preprint
Authors: Bernstein Jeremy
Published: January 2017

The capture of a muon bound to an atomic nucleus is a singular phenomenon because it involves three forces: an electromagnetic force binds the muon to the nucleus and produces the muon's energy levels, including the hyperfine structure; the nuclear force produces the structure of the nucleus; and finally, the weak force is responsible for the capture. In this note, I describe the rather bizarre circumstances under which the first paper discussing the role of the hyperfine levels in this process was written in 1958.
Beyond the Point Charge: Equipotential Surfaces and Electric Fields of Various Charge Configurations
Authors: Phillips Jeffrey A. , Sanny Jeff , Berube David , Hoemke Anatol
Published: January 2017

A laboratory experiment often performed in an introductory electricity and magnetism course involves the mapping of equipotential lines on a conductive sheet between two objects at different potentials. In this article, we describe how we have expanded this experiment so that it can be used to illustrate the electrostatic properties of conductors. Different configurations of electrodes can be used to show that the electric field is zero inside a conductor as well as within a cavity, the electric field is perpendicular to conducting surfaces, and the charge distribution on conducting surfaces can vary.
The Scientific Legacy of Charles Wheatstone
Authors: Greenslade Thomas B.
Published: January 2017

Charles Wheatstone’s name was once familiar to students because they used his eponymous bridge to measure resistances. That usage seems to be disappearing—we all have access to digital ohmmeters—but the techniques that he developed for making electrical measurements can still be used with profit. Also, his work with measuring very short time intervals and his work with musical acoustics are still with us, if in modified forms. Here are a few examples of his work.
Students Learning Physics While Lifting Themselves: A Simple Analysis of a Scissors Jack
Authors: Haugland Ole Anton
Published: January 2017

Every time I have to jack up my car, I am a bit surprised by how slowly the scissors jack works the higher I raise it, and close to maximum height I need very little force to turn the crank. This agrees well with the principle of simple machines. Since I have to jack up my car at least twice a year to change between winter tires and summer tires, I thought it was time to take a closer look at the physics behind the process. And like most physics teachers, I am always looking for new ideas for my teaching. In this note I will present a few ideas on how a jack can be a topic in physics teaching.