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1.
Phys Rev Lett ; 131(6): 060803, 2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37625060

RESUMO

The quantum switch is an example of a process with an indefinite causal structure, and has attracted attention for its ability to outperform causally ordered computations within the quantum circuit model. To date, realizations of the quantum switch have made a trade-off between relying on optical interferometers susceptible to minute path length fluctuations and limitations on the range and fidelity of the implementable channels, thereby complicating their design, limiting their performance, and posing an obstacle to extending the quantum switch to multiple parties. In this Letter, we overcome these limitations by demonstrating an intrinsically stable quantum switch utilizing a common-path geometry facilitated by a novel reciprocal and universal SU(2) polarization gadget. We certify our design by successfully performing a channel discrimination task with near unity success probability.

2.
Transgenic Res ; 31(4-5): 489-504, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35798930

RESUMO

Genetic engineering of mosquitoes represents a promising tactic for reducing human suffering from malaria. Gene-drive techniques being developed that suppress or modify populations of Anopheles gambiae have the potential to be used with, or even possibly obviate, microbial and synthetic insecticides. However, these techniques are new and therefore there is attendant concern and uncertainty from regulators, policymakers, and the public about their environmental risks. Therefore, there is a need to assist decision-makers and public health stewards by assessing the risks associated with these newer mosquito management tactics so the risks can be compared as a basis for informed decision making. Previously, the effect of gene-drive mosquitoes on water quality in Africa was identified as a concern by stakeholders. Here, we use a comparative risk assessment approach for the effect of gene-drive mosquitoes on water quality in Africa. We compare the use of existing larvicides and the proposed genetic techniques in aquatic environments. Based on our analysis, we conclude that the tactic of gene-drive Anopheles for malaria management is unlikely to result in risks to aquatic environments that exceed current tactics for larval mosquitoes. As such, these new techniques would likely comply with currently recommended safety standards.


Assuntos
Anopheles , Inseticidas , Malária , Animais , Anopheles/genética , Ecossistema , Humanos , Larva/genética , Malária/prevenção & controle , Controle de Mosquitos/métodos
3.
RNA Biol ; 18(8): 1181-1192, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33131423

RESUMO

La-related proteins 7 (LARP7) are a class of RNA chaperones that bind the 3' ends of RNA and are constitutively associated with their specific target RNAs. In metazoa, Larp7 binds to the long non-coding 7SK RNA as a core component of the 7SK RNP, a major regulator of eukaryotic transcription. In the ciliate Tetrahymena the LARP7 protein p65 is a component of telomerase, an essential ribonucleoprotein complex that maintains the telomeric DNA at eukaryotic chromosome ends. p65 is important for the ordered assembly of telomerase RNA (TER) with telomerase reverse transcriptase. Unexpectedly, Schizosaccharomyces pombe Pof8 was recently identified as a LARP7 protein and a core component of fission yeast telomerase essential for biogenesis. LARP7 proteins have a conserved N-terminal La motif and RRM1 (La module) and C-terminal RRM2 with specific RNA substrate recognition attributed to RRM2, first structurally characterized in p65 as an atypical RRM named xRRM. Here we present the X-ray crystal structure and NMR studies of S. pombe Pof8 RRM2. Sequence and structure comparison of Pof8 RRM2 to p65 and human Larp7 xRRMs reveals conserved features for RNA binding with the main variability in the length of the non-canonical helix α3. This study shows that Pof8 has conserved xRRM features, providing insight into TER recognition and the defining characteristics of the xRRM.


Assuntos
Proteínas com Motivo de Reconhecimento de RNA/química , RNA/química , Ribonucleoproteínas/química , Proteínas de Schizosaccharomyces pombe/química , Schizosaccharomyces/química , Tetrahymena thermophila/química , Sequência de Aminoácidos , Sítios de Ligação , Clonagem Molecular , Sequência Conservada , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , RNA/genética , RNA/metabolismo , Proteínas com Motivo de Reconhecimento de RNA/genética , Proteínas com Motivo de Reconhecimento de RNA/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Tetrahymena thermophila/genética , Tetrahymena thermophila/metabolismo
4.
J Insect Sci ; 21(4)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34369564

RESUMO

The recent introduction of the Asian giant hornet, Vespa mandarinia Smith, in the United States in late 2019 has raised concerns about its establishment in the Pacific Northwest and its potential deleterious effects on honey bees, Apis spp., and their pollination services in the region. Therefore, we conducted a risk assessment of the establishment of V. mandarinia in Washington, Oregon, Montana, and Idaho on a county-by-county basis. Our highly conservative tier-1 qualitative and semiquantitative risk assessment relied on the biological requirements and ecological relationships of V. mandarinia in the environments of the Pacific Northwest. Our risk characterization was based on climate and habitat suitability estimates for V. mandarinia queens to overwinter and colonize nests, density and distribution of apiaries, and locations of major human-mediated introduction pathways that may increase establishment of the hornet in the counties. Our results suggest that 32 counties in the region could be at low risk, 120 at medium risk, and 23 at high risk of establishment. Many of the western counties in the region were estimated to be at the highest risk of establishment mainly because of their suitable climate for queens to overwinter, dense forest biomass for nest colonization, and proximity to major port and freight hubs in the region. By design, our tier-1 risk assessment most likely overestimates the risk of establishment, but considering its negative effects, these counties should be prioritized in ongoing monitoring and eradication efforts of V. mandarinia.


Assuntos
Espécies Introduzidas , Vespas , Animais , Abelhas , Clima , Monitorização de Parâmetros Ecológicos , Ecossistema , Medição de Risco , Estados Unidos , Vespas/fisiologia
5.
Pediatr Emerg Care ; 37(7): 343-347, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32149997

RESUMO

BACKGROUND AND OBJECTIVE: Dexamethasone has emerged as a viable alternative to prednisone in the treatment of pediatric acute asthma exacerbations, with the potential for improved compliance secondary to decreased frequency of dosing, improved taste, and decreased cost. The objective of this study is to identify whether providers are prescribing dexamethasone for pediatric acute asthma exacerbations. Secondary objectives are to describe variation in practice between different specialties and to identify the commonly used dosing and frequency for dexamethasone. METHODS: We conducted a cross-sectional, descriptive study with an anonymous, web-based survey (surveymonkey.com). The survey population included all fellowship program directors listed on FRIEDA Online for pediatric emergency medicine, pediatric pulmonology, and allergy and immunology, and emergency medicine residency directors through the Council of Emergency Medicine Residency Directors listserv. Program directors were contacted via e-mail up to 5 times for 3 months. RESULTS: Overall, 300 respondents (70% of the program directors) completed the survey. Response rates by specialty varied from 60% to 94%. One third of providers are using dexamethasone, whereas just more than half of providers (51%) are prescribing a 5-day prednisone course. The preferred maximum dose for dexamethasone is 10 mg (45%), with 82% using a dose of 0.6 mg/kg.Pediatric emergency medicine fellowship directors demonstrated a preference for dexamethasone (59%). Prednisone is favored by emergency medicine (56%), pediatric pulmonology (89%), and allergy and immunology (93%) program directors. CONCLUSIONS: Although most pediatric emergency medicine academic physicians have transitioned to using dexamethasone to treat acute pediatric asthma exacerbations, other specialties continue to favor prednisone.


Assuntos
Asma , Especialização , Administração Oral , Asma/tratamento farmacológico , Criança , Estudos Transversais , Dexametasona/uso terapêutico , Humanos , Prednisona/uso terapêutico
6.
J Chem Ecol ; 46(4): 378-386, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32240481

RESUMO

Before weed biocontrol insects are transported and released in a new area, they are commonly collected into small paper containers, chilled, and kept under dark conditions. This process can be termed a pre-release protocol. The influence of a pre-release protocol on establishment success of a gregarious biological control agent was assessed using the northern tamarisk beetle, Diorhabda carinulata (Desbrochers), and its exotic, invasive host plant saltcedar (Tamarix spp.). Pre-release protocol impacts on aggregation pheromone production by D. carinulata were characterized under controlled conditions. Additional experiments were undertaken to determine if deployment of aggregation pheromone lures might enhance the agent's persistence at release sites. Adults that experienced the pre-release protocol produced less aggregation pheromone compared to undisturbed adults. Olfactometer bioassays indicated that a cohort of adults subjected to the pre-release protocol were less attractive to other adults than a control cohort. Efficacy of aggregation pheromone-based lures to retain adults at release sites was evaluated by comparing capture numbers of adult beetles at paired treatment and control release sites, 10-14 days after the release of 300, 500, or 1000 individuals. A greater number of adult D. carinulata were captured where the pheromone lures had been deployed compared to control release sites. Application of aggregation pheromone when a new release of D. carinulata is planned should allow biological control practitioners to increase retention of beetles at a release site.


Assuntos
Besouros/fisiologia , Controle Biológico de Vetores , Feromônios/metabolismo , Tamaricaceae , Controle de Plantas Daninhas , Animais , Besouros/metabolismo , Espécies Introduzidas , Dinâmica Populacional
7.
J Insect Sci ; 20(5)2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32960968

RESUMO

Wheat stem sawfly, Cephus cinctus Norton, is an economically serious pest of cereals grown in North America. Barley cultivars were previously planted as resistant crops in rotations to manage C. cinctus, but due to increasing levels of injury to this crop, this is no longer a valid management tactic in Montana. Therefore, we aimed to understand antixenosis (behavioral preference), antibiosis (mortality), and potential yield compensation (increased productivity in response to stem injuries) in barley exposed to C. cinctus. We examined these traits in eight barley cultivars. Antixenosis was assessed by counting number of eggs per stem and antibiosis was assessed by counting infested stems, dead larvae, and stems cut by mature larvae. Potential yield compensation was evaluated by comparing grain yield from three categories of stem infestation: 1) uninfested, 2) infested with dead larva, and 3) infested cut by mature larva at crop maturity. We found the greatest number of eggs per infested stem (1.80 ± 0.04), the highest proportion of infested stems (0.63 ± 0.01), and the highest proportion of cut stems (0.33 ± 0.01) in 'Hockett'. Seven out of eight cultivars had greater grain weight for infested stems than for uninfested stems. These cultivars may have compensatory responses to larval feeding injury. Overall, these barley cultivars contain varying levels of antixenosis, antibiosis, and differing levels of yield compensation. Our results provide foundational knowledge on barley traits that will provide a framework to further develop C. cinctus resistant or tolerant barley cultivars.


Assuntos
Herbivoria , Hordeum/fisiologia , Himenópteros/fisiologia , Defesa das Plantas contra Herbivoria , Animais , Himenópteros/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia
8.
J Dairy Sci ; 102(10): 8691-8695, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421885

RESUMO

Potato pectin has unique molecular characteristics that differentiate it from commercially available pectins sourced from citrus peels or apple pomace, including a higher degree of branching and a higher acetyl content. The objective of this study was to evaluate the ability of potato pectin to stabilize milk proteins at an acidic pH above their isoelectric point, pH 5.5, at which no citrus- or apple-derived pectins are functional. Potato pectin was extracted from raw potato tubers by heating at pH 4.5 and 120°C for 30 min after removing starch solubilized using a dilute HCl solution adjusted to pH 2. The potato pectin was found to have a galacturonic acid content of 17.31 ± 3.29% (wt/wt) and a degree of acetylation of 20.20 ± 0.12%. A portion of the potato pectin was deacetylated by heating it in an alkaline condition. The deacetylation resulted in a galacturonic acid content of 19.12 ± 4.64% (wt/wt) and a degree of acetylation of 3.03 ± 0.03%. Particle size distributions in acidified milk drink (AMD) samples adjusted to pH 5.5 demonstrated that the acetylated and deacetylated potato pectins were capable of inhibiting the aggregation of milk proteins to the largest degree at a pectin concentration of 1.0 and 0.25% (wt/wt), respectively. Pectin molecules that were not bound to milk proteins in these AMD samples were quantified after centrifugally separating milk proteins and pectin bound to them from the serum. We found that, for the acetylated and deacetylated potato pectins, all or approximately half of the pectin molecules were bound to milk proteins at a pectin concentration of 0.25 or 1.0% (wt/wt), respectively. These results suggest that the presence of acetyl groups is a critical factor that determines how potato pectin molecules bind electrostatically to milk protein surfaces, form 3-dimensional structures there, and function as a stabilizer. The present results demonstrate that potato pectin can stabilize milk proteins at pH 5.5 and potentially enable the development of novel AMD products with improved functionality for casein-containing products with moderately acidic pH profiles.


Assuntos
Proteínas do Leite/química , Pectinas/química , Solanum tuberosum/química , Animais , Caseínas/análise , Ácidos Hexurônicos/análise , Concentração de Íons de Hidrogênio , Leite/química , Tubérculos/química , Polissacarídeos/química , Estabilidade Proteica
9.
Theor Appl Genet ; 130(1): 187-197, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27709252

RESUMO

KEY MESSAGE: Genetic diversity in quantitative loci associated with plant traits used by insects as cues for host selection can influence oviposition behavior and maternal choice. Host plant selection for oviposition is an important determinant of progeny performance and survival for phytophagous insects. Specific cues from the plant influence insect oviposition behavior; but, to date, no set of host plant quantitative trait loci (QTLs) have been shown to have an effect on behavioral sequences leading to oviposition. Three QTLs in wheat (Triticum aestivum L.) have been identified as influencing resistance to the wheat stem sawfly (WSS) (Cephus cinctus Norton). Wheat near-isogenic lines (NILs) for each of the three QTLs were used to test whether foraging WSS were able to discriminate variation in plant cues resulting from allelic changes. A QTL on chromosome 3B (Qss-msub-3BL) previously associated with stem solidness and larval antibiosis was shown to affect WSS oviposition behavior, host preference, and field infestation. Decreased preference for oviposition was also related to a QTL allele on chromosome 2D (Qwss.msub-2D). A QTL on chromosome 4A (Qwss.msub-4A.1) affected host plant attractiveness to foraging females, but did not change oviposition preference after females landed on the stem. These findings show that oviposition decisions regarding potential plant hosts require WSS females to discriminate signals from the plant associated with allelic variation at host plant quantitative loci. Allele types in a host plant QTL associated with differential survival of immature progeny can affect maternal choices for oviposition. The multidisciplinary approach used here may lead to the identification of plant genes with important community consequences, and may complement the use of antibiosis due to solid stems to control the wheat stem sawfly in agroecosystems.


Assuntos
Himenópteros/fisiologia , Oviposição , Locos de Características Quantitativas , Triticum/genética , Alelos , Animais , Feminino , Larva , Caules de Planta/fisiologia , Triticum/fisiologia
11.
Mol Cell ; 33(6): 784-90, 2009 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-19285444

RESUMO

The modified nucleotide queuosine (Q) is almost universally found in the anticodon wobble position of specific tRNAs. In many bacteria, biosynthesis of Q is modulated by a class of regulatory mRNA elements called riboswitches. The preQ(1) riboswitch, found in the 5'UTR of bacterial genes involved in synthesis of the Q precursors preQ(0) and preQ(1), contains the smallest known aptamer domain. We report the solution structure of the preQ(1) riboswitch aptamer domain from Bacillus subtilis bound to preQ(1), which is a unique compact pseudoknot with three loops and two stems that encapsulates preQ(1) at the junction between the two stems. The pseudoknot only forms in the presence of preQ(1), and the 3' A-rich tail of the aptamer domain is an integral part of the pseudoknot. In the absence of preQ(1), the A-rich tail forms part of the antiterminator. These structural studies provide insight into riboswitch transcriptional control of preQ(1) biosynthesis.


Assuntos
Anticódon/química , Aptâmeros de Nucleotídeos/química , Regulação Bacteriana da Expressão Gênica , Nucleosídeo Q/metabolismo , RNA Bacteriano/química , RNA de Transferência/química , Regiões 3' não Traduzidas/genética , Anticódon/genética , Aptâmeros de Nucleotídeos/genética , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Pareamento de Bases , Sequência de Bases , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Nucleosídeo Q/química , Nucleosídeo Q/genética , Conformação Proteica , RNA Bacteriano/genética , RNA de Transferência/genética
12.
J Med Entomol ; 53(1): 139-43, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26477050

RESUMO

Insecticides are the most common strategy used for the management of mosquitoes. Changes in ambient temperature can alter the toxicity of insecticides to ectothermic organisms. Studies show organophosphate insecticides exhibit a positive correlation between ambient temperature and mortality for many insect species, and carbamate insecticides exhibit a slightly negative correlation between ambient temperature and mortality. Pyrethroid insecticides exhibit a distinctly negative correlation between increasing ambient temperature and mortality for insects. However, this relationship has not been systematically studied for adult mosquitoes. Therefore, we examined the influence of temperature on the susceptibility of adult Aedes aegypti L. (Diptera: Culicidae) when exposed to permethrin. The median lethal concentration, LC50, was estimated for adult Ae. aegypti when exposed to eight concentrations of permethrin (ranging from 0.06­0.58 ng/cm2) at each of the following temperatures­16, 23, 26, 30, 32, and 34C­for 24 h in bottle assays. The estimated LC50 for each temperature was 0.26, 0.36, 0.36, 0.45, 0.27, and 0.31 ng/cm2, respectively. Results indicated a negative correlation between temperature and mortality from 16 to 30C, a positive correlation between temperature and mortality from 30 to 32C, and a negative correlation between temperature and mortality from 32 to 34C. If mosquito populations are expanding in space and time because of increased ambient temperatures and cannot be managed as effectively with pyrethroids, the spread of mosquito-borne diseases may pose considerable additional risk to public health.


Assuntos
Aedes , Inseticidas , Permetrina , Animais , Feminino , Dose Letal Mediana , Temperatura
13.
Am J Emerg Med ; 33(10): 1364-7, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26321165

RESUMO

BACKGROUND AND OBJECTIVE: Weight estimation for pediatric resuscitation occurs frequently in emergency departments. Historically, different approaches to estimation have been studied with varied results. With increasing obesity rates among inner-city children, this study aims to determine the best method for pediatric weight estimation in our population. METHODS: This is a prospective, nonblinded, observational study. A total of 324 patients (aged 1 month to 12 years) were enrolled in the study to exceed sample size calculations. The accuracy of 4 methods for weight estimation--the Broselow tape, advanced pediatric life support formulas, the PAWPER tape, and mid-arm circumference formula--were compared across age ranges and body sizes to determine the most appropriate method for our population. RESULTS: In this inner-city population, 32% of the patients 2 to 12 years of age were found to be overweight or obese. This rate increased to 41% for patients 6 to 12 years of age. In this setting, the PAWPER tape outperformed the other 3 methods, estimating patients' weight within ±5% of actual weight in 35.2% of our cohort. When compared with the other 3 methods tested, the PAWPER tape was statistically superior with a P value less than .02 in each case. CONCLUSION: Each of the methods tested in our population performed poorly. Current methods for weight estimation should be used with caution, especially for populations with an increased prevalence of obesity. Efforts should be dedicated to improving or deriving new methods for weight estimation that perform better in this vulnerable population.


Assuntos
Peso Corporal , Pesos e Medidas Corporais/métodos , Obesidade Infantil/complicações , Ressuscitação/métodos , Pesos e Medidas Corporais/instrumentação , Pesos e Medidas Corporais/normas , Criança , Pré-Escolar , Precisão da Medição Dimensional , Feminino , Humanos , Lactente , Masculino , Estudos Prospectivos , Reprodutibilidade dos Testes , Estados Unidos , Saúde da População Urbana
14.
J Am Mosq Control Assoc ; 30(3): 223-7, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25843099

RESUMO

Computer models for pesticide drift are widely used tools by regulatory agencies to estimate the deposition of pesticides beyond the intended target area. Currently, there is no model in use that has been validated or verified as an accurate means of estimating concentrations of insecticides after ground-based ultra-low volume (ULV) applications used for adult mosquito management. To address the need for a validated model we created a spreadsheet-based model called Mosquito Ultra-Low Volume Dispersion (MULV-Disp) to aid in the adoption and to provide easier use of a validated model. We explain the origin, use, and utility of MULV-Disp, which can be used by regulatory agencies and other interested parties to estimate deposition of ULV insecticides.


Assuntos
Culicidae , Meio Ambiente , Inseticidas , Controle de Mosquitos , Animais , Inseticidas/análise , Modelos Teóricos
15.
Sci Adv ; 10(24): eado0215, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38875336

RESUMO

Precision interferometry with quantum states has emerged as an essential tool for experimentally answering fundamental questions in physics. Optical quantum interferometers are of particular interest because of mature methods for generating and manipulating quantum states of light. Their increased sensitivity promises to enable tests of quantum phenomena, such as entanglement, in regimes where tiny gravitational effects come into play. However, this requires long and decoherence-free processing of quantum entanglement, which, for large interferometric areas, remains unexplored territory. Here, we present a table-top experiment using maximally path-entangled quantum states of light in a large-scale interferometer sensitive enough to measure the rotation rate of Earth. The achieved sensitivity of 5 µrad s-1 constitutes the highest rotation resolution ever reached with optical quantum interferometers. Further improvements to our methodology will enable measurements of general-relativistic effects on entangled photons, allowing the exploration of the interplay between quantum mechanics and general relativity, along with tests for fundamental physics.

16.
Environ Entomol ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38986502

RESUMO

The wetsalts tiger beetle, Cicindelidia haemorrhagica (LeConte) (Coleoptera: Cicindelidae), is found in several active thermal hot spring areas in Yellowstone National Park (YNP) where substrate surface temperatures can exceed 50 °C. However, relationships between surface temperatures and the time adults spend on them remain poorly understood. Therefore, we characterized thermal profiles of Dragon Spring and Rabbit Creek, 2 thermally active research sites containing C. haemorrhagica in YNP, to quantify the time adults spend at different surface temperatures. We took 58 thermal video recordings of adults over 6 total days of observation ranging from 10 to 15 min for each adult. Thermal video analysis results indicated a positive relationship between the total time adult beetles spent on surface temperatures from Dragon Spring and Rabbit Creek as temperatures increased from 20 °C. Once surface temperatures exceeded 40 °C, the total time spent at those surface temperatures declined. Adults were recorded on substrates exceeding 50 °C at one of the 2 research locations. Rabbit Creek had substantially more instances of adults present with surface temperatures exceeding 40 °C, including one individual on a surface temperature of 61.5 °C. There were 3 instances of beetles spending more than 4 min at a particular surface temperature, all within the preferred range of 30-40 °C. Our thermal profile results and previous behavioral observations suggest that adults may be resistant to the heat produced from the thermal waters that influence the substrate temperatures but may not be subject to high surface temperatures as previously reported.

17.
PeerJ ; 12: e16827, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38406272

RESUMO

Yellowstone National Park thermal features regularly discharge various heavy metals and metalloids. These metals are taken up by microorganisms that often form mats in thermal springs. These microbial mats also serve as food sources for invertebrate assemblages. To examine how heavy metals move through insect food webs associated with hot springs, two sites were selected for this study. Dragon-Beowulf Hot Springs, acid-sulfate chloride springs, have a pH of 2.9, water temperatures above 70 °C, and populations of thermophilic bacterial, archaeal, and algal mats. Rabbit Creek Hot Springs, alkaline springs, have a pH of up to 9, some water temperatures in excess of 60 °C, and are populated with thermophilic and phototrophic bacterial mats. Mats in both hydrothermal systems form the trophic base and support active metal transfer to terrestrial food chains. In both types of springs, invertebrates bioaccumulated heavy metals including chromium, manganese, cobalt, nickel, copper, cadmium, mercury, tin and lead, and the metalloids arsenic, selenium, and antimony resulting from consuming the algal and bacterial mat biomass. At least two orders of magnitude increase in concentrations were observed in the ephydrid shore fly Paracoenia turbida, as compared to the mats for all metals except antimony, mercury, and lead. The highest bioaccumulation factor (BAF) of 729 was observed for chromium. At the other end of the food web, the invertebrate apex predator, Cicindelidia haemorrhagica, had at least a 10-fold BAF for all metals at some location-year combinations, except with antimony. Of other taxa, high BAFs were observed with zinc for Nebria sp. (2180) and for Salda littoralis (1080). This accumulation, occurring between primary producer and primary consumer trophic levels at both springs, is biomagnified through the trophic web. These observations suggest trace metals enter the geothermal food web through the microbial mat community and are then transferred through the food chain. Also, while bioaccumulation of arsenic is uncommon, we observed five instances of increases near or exceeding 10-fold: Odontomyia sp. larvae (13.6), P. turbida (34.8), C. haemorrhagica (9.7), Rhagovelia distincta (16.3), and Ambrysus mormon (42.8).


Assuntos
Arsênio , Dípteros , Fontes Termais , Mercúrio , Metais Pesados , Animais , Coelhos , Cadeia Alimentar , Fontes Termais/microbiologia , Antimônio , Parques Recreativos , Bactérias , Insetos , Invertebrados , Cromo , Água
18.
Proc Natl Acad Sci U S A ; 107(44): 18761-8, 2010 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-20966348

RESUMO

Telomerase is a unique ribonucleoprotein complex that catalyzes the addition of telomeric DNA repeats onto the 3' ends of linear chromosomes. All vertebrate telomerase RNAs contain a catalytically essential core domain that includes the template and a pseudoknot with extended helical subdomains. Within these helical regions is an asymmetric 5-nt internal bulge loop (J2a/b) flanked by helices (P2a and P2b) that is highly conserved in its location but not sequence. NMR structure determination reveals that J2a/b forms a defined S-shape and creates an ∼90 ° bend with a surprisingly low twist (∼10 °) between the flanking helices. A search of RNA structures revealed only one other example of a 5-nt bulge, from hepatitis C virus internal ribosome entry site, with a different sequence but the same structure. J2a/b is intrinsically flexible but the interhelical motions across the loop are remarkably restricted. Nucleotide substitutions in J2a/b that affect the bend angle, direction, and interhelical dynamics are correlated with telomerase activity. Based on the structures of P2ab (J2a/b and flanking helices), the conserved region of the pseudoknot (P2b/P3, previously determined) and the remaining helical segment (P2a.1-J2a.1 refined using residual dipolar couplings and the modeling program MC-Sym) we have calculated an NMR-based model of the full-length pseudoknot. The model and dynamics analysis show that J2a/b serves as a dominant structural and dynamical element in defining the overall topology of the core domain, and suggest that interhelical motions in P2ab facilitate nucleotide addition along the template and template translocation.


Assuntos
Modelos Moleculares , Conformação de Ácido Nucleico , RNA/química , Telomerase/química , Humanos , Espectroscopia de Ressonância Magnética/métodos
19.
J Econ Entomol ; 116(3): 752-760, 2023 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-37178180

RESUMO

The native parasitoids Bracon cephi (Gahan) and B. lissogaster Muesebeck (Hymenoptera: Braconidae) reduce populations of Cephus cinctus Norton (Hymenoptera: Cephidae), a native grassland species, and major wheat pest on the Northern Great Plains of North America. Non-host feeding adults of these braconids increase longevity, egg load, and egg volume when provisioned carbohydrate-rich diets. Nutrition from nectar can enhance the success of natural enemies in pest management programs. Cowpea, Vigna unguiculata (L.) Walpers, is a potential cover-crop that could add resilient features to the landscape and has extrafloral nectaries (EFN), easy-access nectar sources for beneficial insects. If more cowpea was grown on the Northern Great Plains, would B. cephi and B. lissogaster benefit from foraging on putatively beneficial EFN? We investigated cowpea inflorescence stalk extrafloral nectars (IS-EFN) and leaf stipel extrafloral nectars (LS-EFN) as potential food sources for these parasitoids. Females were caged on EFN sources on living cowpea plants to assess longevity. Egg load and volume were measured at 2, 5, and 10 days after placement. Bracon cephi survived 10 days on water, 38 days on IS-EFN; B. lissogaster 6 days on water, 28 days on IS-EFN. Bracon lissogaster maintained a constant egg load and volume across treatments while B. cephi produced 2.1-fold more eggs that were 1.6-fold larger on IS-EFN. Y-tube olfactometry indicated adult females were attracted to airstreams containing cowpea volatiles. These results demonstrate that non-native, warm-season cowpea benefits these native parasitoids and may improve conservation biocontrol of C. cinctus.


Assuntos
Himenópteros , Vigna , Feminino , Animais , Ecossistema , Néctar de Plantas , Insetos
20.
Environ Entomol ; 52(2): 230-242, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-36801934

RESUMO

The army cutworm, Euxoa auxiliaris (Grote), is a migratory noctuid that is both an agricultural pest and an important late-season food source for grizzly bears, Ursus arctos horribilis (Linnaeus, Carnivora: Ursidae), within the Greater Yellowstone Ecosystem. Beyond the confirmation of the moths' seasonal, elevational migration in the mid-1900s, little else has been documented about their migratory patterns. To address this missing ecological component, we examined (1) migratory routes during their spring and fall migratory periods throughout their natal range, the Great Plains, and (2) natal origin at two of their summering ranges using stable hydrogen (δ2H) analyses of wings from samples collected within the areas of interest. Stable carbon (δ13C) and stable nitrogen (δ15N) analyses of wings were used to evaluate larval feeding habits of the migrants and agricultural intensity of natal origin sites, respectively. Results suggest that, rather than migrating exclusively east to west, army cutworm moths are also migrating north to south during their spring migration. Moths did not exhibit natal origin site fidelity when returning to the Great Plains. Migrants collected from the Absaroka Range had the highest probability of natal origin in Alberta, British Columbia, Saskatchewan, the most southern region of the Northwest Territories, and second highest probability of origin in Montana, Wyoming, and Idaho. Migrants collected in the Lewis Range had the highest probability of origin in the same provinces of Canada. Results suggest that migrants of the Absaroka Range fed exclusively on C3 plants as larvae and rarely fed in heavily fertilized agroecosystems.


Assuntos
Mariposas , Ursidae , Animais , Ecossistema , Larva , Isótopos , Colúmbia Britânica
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