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1.
Mol Biol Rep ; 51(1): 210, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38270754

RESUMO

BACKGROUND: Masked Bobwhite (Colinus virginianus ridgwayi) is a critically-endangered New World quail species endemic to Sonoran Desert grasslands of North America. It suffered severe population declines during the nineteenth and twentieth centuries, with its persistence now reliant upon a captive breeding program that requires careful genetic management to maintain extant genetic diversity. Although nuclear microsatellite DNA markers existed for the closely related Northern Bobwhite (C. virginianus), none were available for Masked Bobwhite to inform necessary management decisions. METHODS AND RESULTS: Paired-end Illumina© sequencing was conducted to screen the Masked Bobwhite genome for microsatellite loci. We identified 18 loci exhibiting high polymorphism and limited deviations from genetic equilibrium expectations. These loci were amplified in 78 individuals. Familial relationships were reconstructed via sibship methods and compared to manually-curated pedigree data. Thirteen of fifteen full-sibling groups in the pedigree were exactly reconstructed (86.6%). Three other full-sibling groups partially matched pedigree relationships with high statistical confidence, and likely represented pedigree inaccuracies. Four additional full-sibling pairs were identified with low statistical confidence and likely resulted from analytical artifacts. CONCLUSIONS: The novel microsatellite loci accurately reconstructed parent-offspring and sibling relationships. These loci will be useful for guiding genetic management decisions and identifying pedigree inaccuracies in the captive breeding program.


Assuntos
Colinus , Humanos , Animais , Cruzamento , Espécies em Perigo de Extinção , Repetições de Microssatélites/genética , América do Norte
2.
Mol Biol Rep ; 50(5): 4743-4751, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36939964

RESUMO

BACKGROUND: Gila topminnow (Poeciliopsis occidentalis occidentalis) was once highly abundant throughout the Lower Colorado River Basin of the southwestern United States. However, this Sonoran Desert endemic suffered extreme population declines over the past century because of habitat degradation and nonnative species introductions. Much of the prior conservation genetic work conducted on the species relied upon a small number of microsatellite loci; many exhibiting low variability in extant populations. Consequently, there was a need for additional microsatellite loci to provide high-resolution delimitation of populations for conservation purposes. METHODS AND RESULTS: Paired-end Illumina sequencing was utilized to screen the Gila topminnow genome for novel microsatellite loci. We identified 21 novel loci that exhibited no deviations from expectations of genetic equilibrium, and cross-amplified in Yaqui topminnow (P. o. sonoriensis). These loci were amplified from 401 samples representing eight populations of Gila topminnow and Yaqui topminnow. Although diversity was low for all populations (observed heterozygosity = 0.12 to 0.45), these novel markers provided ample power to identify population of origin for each individual in Bayesian assignment tests. CONCLUSIONS: This novel set of microsatellite loci provide a useful genetic tool to assess population genetic parameters of the endangered Gila topminnow and delineate populations for identifying conservation priorities. The cross-amplification of these loci in Yaqui topminnow shows promise for application to other Poeciliopsis species of Mexico and Central America.


Assuntos
Fundulidae , Animais , Teorema de Bayes , Frequência do Gene , Heterozigoto , Repetições de Microssatélites/genética , Genética Populacional , Loci Gênicos/genética
3.
J Biol Chem ; 297(2): 100940, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34237302

RESUMO

The severe acute respiratory syndrome coronavirus 2 envelope protein (S2-E) is a conserved membrane protein that is important for coronavirus (CoV) assembly and budding. Here, we describe the recombinant expression and purification of S2-E in amphipol-class amphipathic polymer solutions, which solubilize and stabilize membrane proteins, but do not disrupt membranes. We found that amphipol delivery of S2-E to preformed planar bilayers results in spontaneous membrane integration and formation of viroporin cation channels. Amphipol delivery of the S2-E protein to human cells results in plasma membrane integration, followed by retrograde trafficking to the trans-Golgi network and accumulation in swollen perinuclear lysosomal-associated membrane protein 1-positive vesicles, likely lysosomes. CoV envelope proteins have previously been proposed to manipulate the luminal pH of the trans-Golgi network, which serves as an accumulation station for progeny CoV particles prior to cellular egress via lysosomes. Delivery of S2-E to cells will enable chemical biological approaches for future studies of severe acute respiratory syndrome coronavirus 2 pathogenesis and possibly even development of "Trojan horse" antiviral therapies. Finally, this work also establishes a paradigm for amphipol-mediated delivery of membrane proteins to cells.


Assuntos
Membrana Celular/efeitos dos fármacos , Proteínas do Envelope de Coronavírus/metabolismo , Polímeros/farmacologia , Propilaminas/farmacologia , Tensoativos/farmacologia , Rede trans-Golgi/metabolismo , Membrana Celular/metabolismo , Proteínas do Envelope de Coronavírus/genética , Células HeLa , Humanos , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Lisossomos/metabolismo , Polímeros/química , Propilaminas/química , Transporte Proteico , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tensoativos/química
4.
J Pediatr ; 242: 245-247.e1, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34715091

RESUMO

Current guidelines support the use of a cardiac monitor during neonatal resuscitation. Infants born preterm randomized to a novel electrocardiogram algorithm displayed a heart rate sooner than the conventional electrocardiogram algorithm. Although resuscitation outcomes were not different, the availability of an earlier heart rate may benefit neonatal providers during high-risk resuscitations. TRIAL REGISTRATION: ClinicalTrials.govNCT04587934.


Assuntos
Recém-Nascido Prematuro , Ressuscitação , Algoritmos , Eletrocardiografia , Frequência Cardíaca , Humanos , Lactente , Recém-Nascido , Projetos Piloto
5.
J Pediatr ; 223: 51-56.e1, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32482392

RESUMO

OBJECTIVE: To evaluate changes in cerebral oxygenation, peripheral arterial oxygenation, respiratory status, and administered fraction of inspired oxygen during the first 10 minutes of life in premature infants receiving umbilical cord milking compared with delayed cord clamping (DCC). STUDY DESIGN: Premature infants born at 230/7 to 276/7 weeks of gestation were randomized to umbilical cord milking or DCC. A near infrared spectroscopy sensor, pulse oximeter, and electrocardiogram electrodes were placed. Pulse rate, cerebral tissue oxygenation, peripheral oxygen saturation, airway pressure, and fraction of inspired oxygen were collected for 10 minutes in the delivery room. Longitudinal models were used to compare effects of umbilical cord milking and DCC. RESULTS: Fifty-six infants had cerebral oximetry and advanced monitoring at birth. There was an increased incidence of severe intraventricular hemorrhage in infants who received umbilical cord milking compared with DCC (P = .0211). Longitudinal models suggested that peripheral oxygen saturation was higher in the umbilical cord milking group in the first 4 minutes (P = .0221) and that mean airway pressures were lower in the umbilical cord milking group after the first 7 minutes (P = .0072). No statistical differences were observed for fraction of inspired oxygen, cerebral tissue oxygenation, or heart rates. CONCLUSIONS: The data suggest that the rapid transfer of blood during umbilical cord milking may facilitate lung expansion with improved pulmonary blood flow, but may also increase cerebral blood flow, resulting in severe intraventricular hemorrhage. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03145142.


Assuntos
Circulação Cerebrovascular , Parto Obstétrico/métodos , Hemodinâmica/fisiologia , Pulmão/irrigação sanguínea , Cordão Umbilical/irrigação sanguínea , Adulto , Hemorragia Cerebral Intraventricular/etiologia , Parto Obstétrico/efeitos adversos , Feminino , Humanos , Lactente Extremamente Prematuro , Recém-Nascido , Gravidez , Resultado da Gravidez/epidemiologia , Espectroscopia de Luz Próxima ao Infravermelho , Fatores de Tempo
6.
Acc Chem Res ; 52(6): 1643-1652, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31149807

RESUMO

The familiar pungent taste of spicy food, the refreshing taste of mint, and many other physiological phenomena are mediated by transient receptor potential (TRP) ion channels. TRP channels are a superfamily of ion channels that are sensitive to diverse chemical and physical stimuli and play diverse roles in biology. In addition to chemical regulation, some family members also sense common physical stimuli, such as temperature or pressure. Since their discovery and cloning in the 1990s and 2000s, understanding the molecular mechanisms governing TRP channel function and polymodal regulation has been a consistent but challenging goal. Until recently, a general lack of high-resolution TRP channel structures had significantly limited a molecular understanding of their function. In the past few years, a flood of TRP channel structures have been released, made possible primarily by advances in cryo-electron microscopy (cryo-EM). The boon of many structures has unleashed unparalleled insight into TRP channel architecture. Substantive comparative studies between TRP structures provide snapshots of distinct states such as ligand-free, stabilized by chemical agonists, or antagonists, partially illuminating how a given channel opens and closes. However, the now ∼75 TRP channel structures have ushered in surprising outcomes, including a lack of an apparent general mechanism underlying channel opening and closing among family members. Similarly, the structures reveal a surprising diversity in which chemical ligands bind TRP channels. Several TRP channels are activated by temperature changes in addition to ligand binding. Unraveling mechanisms of thermosensation has proven an elusive challenge to the field. Although some studies point to thermosensitive domains in the transmembrane region of the channels, results have sometimes been contradictory and difficult to interpret; in some cases, a domain that proves essential for thermal sensitivity in one context can be entirely removed from the channel without affecting thermosensation in another context. These results are not amenable to simple interpretations and point to allosteric networks of regulation within the channel structure. TRP channels have evolved to be fine-tuned for the needs of a species in its environmental niche, a fact that has been both a benefit and burden in unlocking their molecular features. Functional evolutionary divergence has presented challenges for studying TRP channels, as orthologs from different species can give conflicting experimental results. However, this diversity can also be examined comparatively to decipher the basis for functional differences. As with structural biology, untangling the similarities and differences resulting from evolutionary pressure between species has been a rich source of data guiding the field. This Account will contextualize the existing biochemical and functional data with an eye to evolutionary data and couple these insights with emerging structural biology to better understand the molecular mechanisms behind chemical and physical regulation of TRP channels.


Assuntos
Evolução Molecular , Canais de Potencial de Receptor Transitório/química , Regulação Alostérica , Animais , Sítios de Ligação , Humanos , Ligantes , Camundongos , Mutação , Ligação Proteica , Domínios Proteicos , Temperatura , Canais de Potencial de Receptor Transitório/genética , Canais de Potencial de Receptor Transitório/metabolismo
7.
J Biol Chem ; 293(24): 9423-9434, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29724821

RESUMO

Transient receptor potential melastatin 8 (TRPM8) is a cold-sensitive ion channel with diverse physiological roles. TRPM8 activity is modulated by many mechanisms, including an interaction with the small membrane protein phosphoinositide-interacting regulator of TRP (PIRT). Here, using comparative electrophysiology experiments, we identified species-dependent differences between the human and mouse TRPM8-PIRT complexes. We found that human PIRT attenuated human TPRM8 conductance, unlike mouse PIRT, which enhanced mouse TRPM8 conductance. Quantitative Western blot analysis demonstrates that this effect does not arise from decreased trafficking of TRPM8 to the plasma membrane. Chimeric human/mouse TRPM8 channels were generated to probe the molecular basis of the PIRT modulation, and the effect was recapitulated in a pore domain chimera, demonstrating the importance of this region for PIRT-mediated regulation of TRPM8. Moreover, recombinantly expressed and purified human TRPM8 S1-S4 domain (comprising transmembrane helices S1-S4, also known as the sensing domain, ligand-sensing domain, or voltage sensing-like domain) and full-length human PIRT were used to investigate binding between the proteins. NMR experiments, supported by a pulldown assay, indicated that PIRT binds directly and specifically to the TRPM8 S1-S4 domain. Binding became saturated as the S1-S4:PIRT mole ratio approached 1. Our results have uncovered species-specific TRPM8 modulation by PIRT. They provide evidence for a direct interaction between PIRT and the TRPM8 S1-S4 domain with a 1:1 binding stoichiometry, suggesting that a functional tetrameric TRPM8 channel has four PIRT-binding sites.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Membrana/metabolismo , Canais de Cátion TRPM/metabolismo , Animais , Proteínas de Transporte/química , Células HEK293 , Humanos , Proteínas de Membrana/química , Camundongos , Modelos Moleculares , Domínios e Motivos de Interação entre Proteínas , Mapas de Interação de Proteínas , Especificidade da Espécie , Canais de Cátion TRPM/química
8.
Eur J Neurol ; 26(3): 435-441, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30308699

RESUMO

BACKGROUND AND PURPOSE: The aim was to evaluate the tolerability of, adherence to and efficacy of a community walking training programme with simultaneous cognitive demand (dual-task) compared to a control walking training programme without cognitive distraction. METHODS: Adult stroke survivors at least 6 months after stroke with a visibly obvious gait abnormality or reduced 2-min walk distance were included in a two-arm parallel randomized controlled trial of complex intervention with blinded assessments. Participants received a 10 week, bi-weekly, 30 min treadmill programme at an aerobic training intensity (55%-85% heart rate maximum), either with or without simultaneous cognitive demands. Outcome was measured at 0, 11 and 22 weeks. The primary assessment involved 2-min walk tests with and without cognitive distraction to investigate the dual-task effect on walking and cognition; secondary results were the Short Form Health Survey 36, EuroQol-5D-5L, the Physical Activity Scale for the Elderly (PASE) and step activity. RESULTS: Fifty stroke patients were included; 43 received allocated training and 45 completed all assessments. The experimental group (n = 26) increased their mean (SD) 2-min walking distance from 90.7 (8.2) to 103.5 (8.2) m, compared with 86.7 (8.5) to 92.8 (8.6) m in the control group, and their PASE score from 74.3 (9.1) to 89.9 (9.4), compared with 94.7 (9.4) to 77.3 (9.9) in the control group. Statistically, only the change in the PASE differed between the groups (P = 0.029), with the dual-task group improving more. There were no differences in other measures. CONCLUSIONS: Walking with specific additional cognitive distraction (dual-task training) might increase activity more over 12 weeks, but the data are not conclusive.


Assuntos
Função Executiva , Terapia por Exercício/métodos , Avaliação de Processos e Resultados em Cuidados de Saúde , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/terapia , Caminhada , Adulto , Idoso , Idoso de 80 Anos ou mais , Função Executiva/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Caminhada/fisiologia
9.
JAAPA ; 32(3): 51-53, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30817482

RESUMO

This article discusses developments in total hip arthroplasty related to the use of highly cross-linked polyethylene (HXLPE) liner material as the new standard of care for acetabular cup articulation surfaces. The pathologic implications of metal-on-metal hip prostheses in asymptomatic patients also are discussed.


Assuntos
Artroplastia de Quadril/tendências , Polietileno , Acetábulo , Granuloma de Células Plasmáticas/diagnóstico , Granuloma de Células Plasmáticas/etiologia , Granuloma de Células Plasmáticas/prevenção & controle , Prótese de Quadril/efeitos adversos , Humanos , Próteses Articulares Metal-Metal/efeitos adversos , Monitorização Fisiológica , Osteólise/diagnóstico , Osteólise/etiologia , Osteólise/prevenção & controle , Desenho de Prótese , Risco
10.
J Pediatr ; 193: 40-46.e1, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29174079

RESUMO

OBJECTIVE: To determine if preterm infants with moderate respiratory distress syndrome on continuous positive airway pressure (CPAP) who received surfactant via a laryngeal mask airway (LMA) would have a decreased rate of intubation and mechanical ventilation compared with those on CPAP who did not receive surfactant. STUDY DESIGN: In this prospective, multicenter, randomized controlled trial, 103 premature infants 280/7-356/7 weeks gestation, ≥1250 g and ≤36 hours old on CPAP requiring fraction of inspired oxygen 0.30-0.40 were assigned to receive surfactant administered through an LMA then placed back on CPAP (LMA group) or maintained on CPAP with no surfactant administered (control group). The primary outcome was treatment failure necessitating intubation and mechanical ventilation in the first 7 days of life. RESULTS: Surfactant administration through an LMA (n = 50) significantly decreased the rate of intubation and mechanical ventilation compared with controls (n = 53): 38% vs 64%, respectively, OR 0.30 (95% CI 0.13, 0.70), P = .006, number needed to treat: 4). There were no serious adverse events associated with placement of the LMA or surfactant administration. CONCLUSIONS: In premature neonates with moderate respiratory distress syndrome, surfactant administered through an LMA decreased the rate of intubation and mechanical ventilation. This intervention may have significant impact on clinical care in both high and low resource settings. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01116921.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas/métodos , Máscaras Laríngeas , Surfactantes Pulmonares/administração & dosagem , Síndrome do Desconforto Respiratório do Recém-Nascido/terapia , Pressão Positiva Contínua nas Vias Aéreas/efeitos adversos , Pressão Positiva Contínua nas Vias Aéreas/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Intubação Intratraqueal/estatística & dados numéricos , Masculino , Estudos Prospectivos , Falha de Tratamento , Resultado do Tratamento
11.
Eur J Neurol ; 25(4): 619-625, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29338107

RESUMO

Some research suggests that 40% of people in the vegetative state are misdiagnosed. This review investigates the frequency, nature and causes of reported misdiagnosis of patients in the vegetative state, focusing on the nature of the error. It is a systematic review of all relevant literature, using references from key papers identified. The data are summarized in tables. Five clinical studies of the rate of misdiagnosis in practice were identified, encompassing 236 patients in the vegetative state of whom 80 (34%) were reclassified as having some awareness, often minimal. The studies often included patients in the recovery phase after acute injury, and were poorly reported. Five systematic reviews of signs and technologically based neurophysiological tests were identified, and they showed that most studies were small, lacked accurate or important details, and were subject to bias. Studies were not replicated. Many signs and tests did not differ between people in the vegetative state and in the minimally conscious state, and those that did were unable to diagnose an individual patient. The few single case reports suggest that failure to ensure an accurate diagnosis of the underlying neurological damage and dysfunction could, rarely, lead to significant misdiagnosis usually in patients who had brain-stem damage with little thalamic or cortical damage. Significant misdiagnosis of awareness, with an apparently 'vegetative' patient having good awareness, is rare. Careful neurological assessment of the cause and routine measurement of awareness using the Coma Recovery Scale - Revised should further reduce mistakes.


Assuntos
Erros de Diagnóstico/estatística & dados numéricos , Estado Vegetativo Persistente/diagnóstico , Humanos
12.
Nucleic Acids Res ; 44(3): 1007-21, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26673703

RESUMO

Synthetic genetics is a subdiscipline of synthetic biology that aims to develop artificial genetic polymers (also referred to as xeno-nucleic acids or XNAs) that can replicate in vitro and eventually in model cellular organisms. This field of science combines organic chemistry with polymerase engineering to create alternative forms of DNA that can store genetic information and evolve in response to external stimuli. Practitioners of synthetic genetics postulate that XNA could be used to safeguard synthetic biology organisms by storing genetic information in orthogonal chromosomes. XNA polymers are also under active investigation as a source of nuclease resistant affinity reagents (aptamers) and catalysts (xenozymes) with practical applications in disease diagnosis and treatment. In this review, we provide a structural perspective on known antiparallel duplex structures in which at least one strand of the Watson-Crick duplex is composed entirely of XNA. Currently, only a handful of XNA structures have been archived in the Protein Data Bank as compared to the more than 100 000 structures that are now available. Given the growing interest in xenobiology projects, we chose to compare the structural features of XNA polymers and discuss their potential to access new regions of nucleic acid fold space.


Assuntos
Ácidos Nucleicos/química , Polímeros/química , Conformação de Ácido Nucleico
13.
Biopolymers ; 107(3)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27718227

RESUMO

G-rich sequences can adopt four-stranded helical structures, called G-quadruplexes, that self-assemble around monovalent cations like sodium (Na+ ) and potassium (K+ ). Whether similar structures can be formed from xeno-nucleic acid (XNA) polymers with a shorter backbone repeat unit is an unanswered question with significant implications on the fold space of functional XNA polymers. Here, we examine the potential for TNA (α-l-threofuranosyl nucleic acid) to adopt a four-stranded helical structure based on a planar G-quartet motif. Using native polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) and solution-state nuclear magnetic resonance (NMR) spectroscopy, we show that despite a backbone repeat unit that is one atom shorter than the backbone repeat unit found in DNA and RNA, TNA can self-assemble into stable G-quadruplex structures that are similar in thermal stability to equivalent DNA structures. However, unlike DNA, TNA does not appear to discriminate between Na+ and K+ ions, as G-quadruplex structures form equally well in the presence of either ion. Together, these findings demonstrate that despite a shorter backbone repeat unit, TNA is capable of self-assembling into stable G-quadruplex structures.


Assuntos
Quadruplex G , Ácidos Nucleicos/química , Tetroses/química , Dicroísmo Circular , Espectroscopia de Ressonância Magnética , Eletroforese em Gel de Poliacrilamida Nativa , Conformação de Ácido Nucleico , Ácidos Nucleicos/síntese química , Oligonucleotídeos/síntese química , Oligonucleotídeos/química
14.
Faraday Discuss ; 200: 475-500, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28580997

RESUMO

Emissions from anthropogenic activity are known to have deleterious impacts on human and ecosystem health and as such a significant amount of time, effort and money has been spent developing legislation to minimise their effects. Here we use a state of the art coupled chemistry-climate model HadGEM2-ES, with extended tropospheric chemistry, to assess the impacts that changes in emissions from anthropogenic activity have had on the burden and impacts of air pollutants over the last three decades. We use HadGEM2-ES to assess an alternative trajectory in air pollutant emissions to that which we have seen, with a regional focus on the contiguous United States and areas of Western Europe. This alternative trajectory can be considered to reflect a world avoided. In this world avoided, the significant levels of air pollution legislation imposed over the last three decades are simulated to not have come into effect in the contiguous United States and Western Europe. Rather a business as usual emission scenario is followed from 1970 to the present day. By combining the results of simulations of the world avoided with a base case present day atmosphere our model runs demonstrate that as a result of air pollution legislation, over 500 000 early mortalities a year have been mitigated owing to extensive reduction in sulfate aerosol and up to 8000 early mortalities a year have been mitigated as a result of improvements in ozone and nitrogen dioxide pollution. These results highlight the important role of legislation in reducing air pollution related mortality in these areas of the globe and highlight a compelling case for developing regions to follow.

15.
Adv Mar Biol ; 77: 111-148, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28882212

RESUMO

Although there is a general perception of sharks as large pelagic, apex predators, most sharks are smaller, meso- and upper-trophic level predators that are associated with the seafloor. Among 73 shark species documented in the eastern North Pacific (ENP), less than half reach maximum lengths >200cm, and 78% occur in demersal or benthic regions of the continental shelf or slope. Most small (≤200cm) species (e.g., houndsharks) and demersal, nearshore juveniles of larger species (e.g., requiem sharks) consume small teleosts and decapod crustaceans, whereas large species in pelagic coastal and oceanic environments feed on large teleosts and squids. Several large, pelagic apex predator species occur in the ENP, but the largest species (i.e., Basking Shark, Whale Shark) consume zooplankton or small nekton. Size-based dietary variability is substantial for many species, and segregation of juvenile and adult foraging habitats also is common (e.g., Horn Shark, Shortfin Mako). Temporal dietary differences are most pronounced for temperate, nearshore species with wide size ranges, and least pronounced for smaller species in extreme latitudes and deep-water regions. Sympatric sharks often occupy various trophic positions, with resource overlap differing by space and time and some sharks serving as prey to other species. Most coastal species remain in the same general region over time and feed opportunistically on variable prey inputs (e.g., season migrations, spawning, or recruitment events), whereas pelagic, oceanic species actively seek hot spots of prey abundance that are spatiotemporally variable. The influence of sharks on ecosystem structure and regulation has been downplayed compared to that of large teleosts species with higher per capita consumption rates (e.g., tunas, billfishes). However, sharks also exert indirect influences on prey populations by causing behavioural changes that may result in restricted ranges and reduced fitness. Except for food web modelling efforts in Alaskan waters, the trophic impacts of sharks are poorly incorporated into current ecosystem approaches to fisheries management in the NEP.


Assuntos
Dieta/veterinária , Cadeia Alimentar , Tubarões/fisiologia , Distribuição Animal , Animais , Comportamento Alimentar , Oceano Pacífico
16.
Biochemistry ; 55(1): 114-24, 2016 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-26653082

RESUMO

The transient receptor potential melastatin 8 (TRPM8) ion channel is the primary cold sensor in humans. TRPM8 is gated by physiologically relevant cold temperatures and chemical ligands that induce cold sensations, such as the analgesic compound menthol. Characterization of TRPM8 ligand-gated channel activation will lead to a better understanding of the fundamental mechanisms that underlie TRPM8 function. Here, the direct binding of menthol to the isolated hTRPM8 sensing domain (transmembrane helices S1-S4) is investigated. These data are compared with two mutant sensing domain proteins, Y745H (S2 helix) and R842H (S4 helix), which have been previously identified in full length TRPM8 to be menthol insensitive. The data presented herein show that menthol specifically binds to the wild type, Y745H, and R842H TRPM8 sensing domain proteins. These results are the first to show that menthol directly binds to the TRPM8 sensing domain and indicates that Y745 and R842 residues, previously identified in functional studies as crucial to menthol sensitivity, do not affect menthol binding but instead alter coupling between the sensing domain and the pore domain.


Assuntos
Mentol/metabolismo , Canais de Cátion TRPM/metabolismo , Sítios de Ligação , Células HEK293 , Humanos , Modelos Moleculares , Mutação Puntual , Ligação Proteica , Estrutura Terciária de Proteína , Canais de Cátion TRPM/química , Canais de Cátion TRPM/genética
17.
Chembiochem ; 17(18): 1705-8, 2016 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-27347671

RESUMO

Threose nucleic acid (TNA) is an artificial genetic polymer capable of heredity and evolution, and is studied in the context of RNA chemical etiology. It has a four-carbon threose backbone in place of the five-carbon ribose of natural nucleic acids, yet forms stable antiparallel complementary Watson-Crick homoduplexes and heteroduplexes with DNA and RNA. TNA base-pairs more favorably with RNA than with DNA but the reason is unknown. Here, we employed NMR, ITC, UV, and CD to probe the structural and dynamic properties of heteroduplexes of RNA/TNA and DNA/TNA. The results indicate that TNA templates the structure of heteroduplexes, thereby forcing an A-like helical geometry. NMR measurement of kinetic and thermodynamic parameters for individual base pair opening events reveal unexpected asymmetric "breathing" fluctuations of the DNA/TNA helix. The results suggest that DNA is unable to fully adapt to the conformational constraints of the rigid TNA backbone and that nucleic acid breathing dynamics are determined from both backbone and base contributions.


Assuntos
Pareamento de Bases , DNA/química , RNA/química , Tetroses/química
18.
JAAPA ; 29(3): 27-31, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26840607

RESUMO

Total knee arthroplasty (TKA) is one of the success stories of modern surgery. Primary TKA is commonly used when nonsurgical treatments for osteoarthritis fail. The need for TKA is projected to increase by 673% between 2005 and 2030, creating a tremendous burden on the healthcare system. This article reviews selected perioperative management strategies, computer-aided navigation, patient-specific cutting blocks, and medial pivot knee implants as potential sources of improvements in clinical efficiency and patient outcomes.


Assuntos
Artroplastia do Joelho , Osteoartrite do Joelho/cirurgia , Humanos , Modelos Anatômicos , Manejo da Dor , Assistência Perioperatória , Cirurgia Assistida por Computador
19.
Crit Rev Biochem Mol Biol ; 48(4): 357-72, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23631591

RESUMO

Human vitamin K epoxide reductase (hVKOR) is a small integral membrane protein involved in recycling vitamin K. hVKOR produces vitamin K hydroquinone, a crucial cofactor for γ-glutamyl carboxylation of vitamin K dependent proteins, which are necessary for blood coagulation. Because of this, hVKOR is the target of a common anticoagulant, warfarin. Spurred by the identification of the hVKOR gene less than a decade ago, there have been a number of new insights related to this protein. Nonetheless, there are a number of key issues that have not been resolved; such as where warfarin binds hVKOR, or if human VKOR shares the topology of the structurally characterized but distantly related prokaryotic VKOR. The pharmacogenetics and single nucleotide polymorphisms of hVKOR used in personalized medicine strategies for warfarin dosing should be carefully considered to inform the debate. The biochemical and cell biological evidence suggests that hVKOR has a distinct fold from its ancestral protein, though the controversy will likely remain until structural studies of hVKOR are accomplished. Resolving these issues should impact development of new anticoagulants. The paralogous human protein, VKOR-like1 (VKORL1) was recently shown to also participate in vitamin K recycling. VKORL1 was also recently characterized and assigned a functional role as a housekeeping protein involved in redox homeostasis and oxidative stress with a potential role in cancer regulation. As the physiological interplay between these two human paralogs emerge, the impacts could be significant in a number of diverse fields from coagulation to cancer.


Assuntos
Oxigenases de Função Mista/metabolismo , Vitamina K Epóxido Redutases/química , Vitamina K Epóxido Redutases/metabolismo , Humanos , Oxigenases de Função Mista/química , Vitamina K/metabolismo , Varfarina/metabolismo
20.
Biochemistry ; 54(15): 2401-13, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25812016

RESUMO

Transient receptor potential (TRP) ion channels are eukaryotic polymodal sensors that function as molecular cellular signal integrators. TRP family members sense and are modulated by a wide array of inputs, including temperature, pressure, pH, voltage, chemicals, lipids, and other proteins. These inputs induce signal transduction events mediated by nonselective cation passage through TRP channels. In this review, we focus on the thermosensitive TRP channels and highlight the emerging view that these channels play a variety of significant roles in physiology and pathophysiology in addition to sensory biology. We attempt to use this viewpoint as a framework to understand the complexity and controversy of TRP channel modulation and ultimately suggest that the complex functional behavior arises inherently because this class of protein is exquisitely sensitive to many diverse and distinct signal inputs. To illustrate this idea, we primarily focus on TRP channel thermosensing. We also offer a structural, biochemical, biophysical, and computational perspective that may help to bring more coherence and consensus in understanding the function of this important class of proteins.


Assuntos
Transdução de Sinais/fisiologia , Canais de Cátion TRPC , Sensação Térmica/fisiologia , Animais , Humanos , Relação Estrutura-Atividade , Canais de Cátion TRPC/química , Canais de Cátion TRPC/genética , Canais de Cátion TRPC/metabolismo
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