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1.
Mol Cell ; 75(3): 442-456.e4, 2019 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-31176671

RESUMO

Insulin gene coding sequence mutations are known to cause mutant INS-gene-induced diabetes of youth (MIDY), yet the cellular pathways needed to prevent misfolded proinsulin accumulation remain incompletely understood. Here, we report that Akita mutant proinsulin forms detergent-insoluble aggregates that entrap wild-type (WT) proinsulin in the endoplasmic reticulum (ER), thereby blocking insulin production. Two distinct quality-control mechanisms operate together to combat this insult: the ER luminal chaperone Grp170 prevents proinsulin aggregation, while the ER membrane morphogenic protein reticulon-3 (RTN3) disposes of aggregates via ER-coupled autophagy (ER-phagy). We show that enhanced RTN-dependent clearance of aggregated Akita proinsulin helps to restore ER export of WT proinsulin, which can promote WT insulin production, potentially alleviating MIDY. We also find that RTN3 participates in the clearance of other mutant prohormone aggregates. Together, these results identify a series of substrates of RTN3-mediated ER-phagy, highlighting RTN3 in the disposal of pathogenic prohormone aggregates.


Assuntos
Proteínas de Transporte/genética , Diabetes Mellitus/genética , Proteínas de Choque Térmico HSP70/genética , Insulina/genética , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Proinsulina/genética , Autofagia/genética , Diabetes Mellitus/patologia , Retículo Endoplasmático/genética , Células HEK293 , Humanos , Insulina/biossíntese , Mutação/genética , Proinsulina/biossíntese , Agregados Proteicos/genética , Dobramento de Proteína , RNA Interferente Pequeno/genética
2.
J Cell Sci ; 136(13)2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37401530

RESUMO

The multi-functional endoplasmic reticulum (ER) is exploited by viruses to cause infection. Morphologically, this organelle is a highly interconnected membranous network consisting of sheets and tubules whose levels are dynamic, changing in response to cellular conditions. Functionally, the ER is responsible for protein synthesis, folding, secretion and degradation, as well as Ca2+ homeostasis and lipid biosynthesis, with each event catalyzed by defined ER factors. Strikingly, these ER host factors are hijacked by viruses to support different infection steps, including entry, translation, replication, assembly and egress. Although the full repertoire of these ER factors that are hijacked is unknown, recent studies have uncovered several ER membrane machineries that are exploited by viruses - ranging from polyomavirus to flavivirus and coronavirus - to facilitate different steps of their life cycle. These discoveries should provide better understanding of virus infection mechanisms, potentially leading to the development of more effective anti-viral therapies.


Assuntos
Viroses , Replicação Viral , Humanos , Replicação Viral/fisiologia , Interações Hospedeiro-Patógeno , Retículo Endoplasmático/metabolismo , Viroses/metabolismo , Chaperonas Moleculares/metabolismo
3.
Arch Toxicol ; 2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38735004

RESUMO

Cultivation of industrial low-Δ9-tetrahydrocannabinol (Δ9-THC) hemp has created an oversupply of cannabidiol (CBD)-rich products. The fact that phytocannabinoids, including CBD, can be used as precursors to synthetically produce a range of THC variants-potentially located in a legal loophole-has led to a diversification of cannabis recreational drug markets. 'Hemp-compliant', 'hemp-derived' and 'semisynthetic' cannabinoid products are emerging and being advertised as (legal) alternatives for Δ9-THC. This study included a large panel (n = 30) of THC isomers, homologs, and analogs that might be derived via semisynthetic procedures. As a proxy for the abuse potential of these compounds, we assessed their potential to activate the CB1 cannabinoid receptor with a ß-arrestin2 recruitment bioassay (picomolar-micromolar concentrations). Multiple THC homologs (tetrahydrocannabihexol, THCH; tetrahydrocannabiphorol, THCP; tetrahydrocannabinol-C8, THC-C8) and THC analogs (hexahydrocannabinol, HHC; hexahydrocannabiphorol, HHCP) were identified that showed higher potential for CB1 activation than Δ9-THC, based on either higher efficacy (Emax) or higher potency (EC50). Structure-activity relationships were assessed for Δ9-THC and Δ8-THC homologs encompassing elongated alkyl chains. Additionally, stereoisomer-specific differences in CB1 activity were established for various THC isomers (Δ7-THC, Δ10-THC) and analogs (HHC, HHCP). Evaluation of the relative abundance of 9(S)-HHC and 9(R)-HHC epimers in seized drug material revealed varying epimeric compositions between batches. Increased abundance of the less active 9(S)-HHC epimer empirically resulted in decreased potency, but sustained efficacy for the resulting diastereomeric mixture. In conclusion, monitoring of semisynthetic cannabinoids is encouraged as the dosing and the relative composition of stereoisomers can impact the harm potential of these drugs, relative to Δ9-THC products.

4.
J Med Virol ; 94(7): 3386-3393, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35277984

RESUMO

Medical instruments that are not autoclavable but may become contaminated with high-risk human papillomaviruses (HPVs) during use must be thoroughly disinfected to avoid the possibility of iatrogenic transmission of infection. There is an expectation that prolonged soaking of instruments in the United States Food and Drug Administration-cleared chemical disinfectant solutions will result in high-level decontamination, but HPV16 and HPV18 are known to be resistant to commonly used formulations. However, they are susceptible to a variety of oxidative agents, including those based on chlorine. Here, we tested the efficacy of homogeneous hypochlorous acid (HOCl) solutions against mature infectious virions of HPV16 and HPV18 dried onto butadiene styrene coupons and ultrasonic probes. Both viruses were inactivated to >4 log reduction value (LRV) after 15 s on coupons and 5 min on ultrasonic probes. Morphologic changes became evident within those contact times by transmission electron microscopy when HPV16 virus-like particles were exposed to HOCl under identical conditions. Mass spectrometry analysis of trypsin-digested products of L1 capsid proteins exposed to HOCl showed that mostly conserved residues were modified by oxidation and that these changes rapidly lead to instability of the protein demonstrable on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Modifications to these residues may contribute to rapid virus inactivation. The use of homogeneous HOCl solutions for HPV decontamination provides a highly effective means of assuring the safety of nonautoclavable medical instruments.


Assuntos
Desinfetantes , Infecções por Papillomavirus , Proteínas do Capsídeo/metabolismo , Desinfetantes/farmacologia , Papillomavirus Humano 16/fisiologia , Humanos , Ácido Hipocloroso/farmacologia , Infecções por Papillomavirus/prevenção & controle
5.
Syst Biol ; 70(6): 1123-1144, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33783539

RESUMO

The use of high-throughput sequencing technologies to produce genome-scale data sets was expected to settle some long-standing controversies across the Tree of Life, particularly in areas where short branches occur at deep timescales. Instead, these data sets have often yielded many well-supported but conflicting topologies, and highly variable gene-tree distributions. A variety of branch-support metrics beyond the nonparametric bootstrap are now available to assess how robust a phylogenetic hypothesis may be, as well as new methods to quantify gene-tree discordance. We applied multiple branch-support metrics to a study of an ancient group of marine fishes (Teleostei: Pelagiaria) whose interfamilial relationships have proven difficult to resolve due to a rapid accumulation of lineages very early in its history. We analyzed hundreds of loci including published ultraconserved elements and newly generated exonic data along with their flanking regions to represent all 16 extant families for more than 150 out of 284 valid species in the group. Branch support was typically lower at inter- than intra-familial relationships regardless of the type of marker used. Several nodes that were highly supported with bootstrap had a very low site and gene-tree concordance, revealing underlying conflict. Despite this conflict, we were able to identify four consistent interfamilial clades, each comprised of two or three families. Combining exons with their flanking regions also produced increased branch lengths at the deep branches of the pelagiarian tree. Our results demonstrate the limitations of employing current metrics of branch support and species-tree estimation when assessing the confidence of ancient evolutionary radiations and emphasize the necessity to embrace alternative measurements to explore phylogenetic uncertainty and discordance in phylogenomic data sets.[Concatenation; exons; introns; phylogenomics; species-tree methods; target capture.].


Assuntos
Benchmarking , Atum , Animais , Evolução Biológica , Peixes , Humanos , Filogenia
6.
J Am Chem Soc ; 142(4): 1731-1734, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31927990

RESUMO

We present the structure of a novel solvate adduct formed by dissolving ferrocene, FeCp2, in hexafluorobenzene, C6F6. This adduct demonstrates the remarkably strong interactions between the five-membered aromatic rings of FeCp2 and the six-membered aromatic ring of C6F6. These molecular interactions are sufficiently strong and anisotropic to change the temperature of the order-disorder transition of the ferrocene molecule from below ca. 164 K to RT. No solvate adduct could be formed between benzene and FeCp2. These observations will be of particular relevance to the crystal engineering community, whose goal is the design of solids with bespoke properties.

7.
J Intensive Care Med ; 35(3): 264-269, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29141527

RESUMO

BACKGROUND: Decreases in mixed venous O2 saturation (SvO2) have been reported to occur in postcardiac surgery patients during weaning from mechanical ventilation. Our aim was to establish whether the physiological mechanism responsible for this phenomenon was a decrease in systemic O2 delivery (DO2) or an increase in global O2 consumption (V˙ O 2). METHODS: We studied 21 mechanically ventilated, postoperative cardiac patients for 30 minutes before and 60 minutes after extubation. We monitored continuously arterial O2 saturation by pulse oximetry (SaO2) and central venous O2 saturation (ScvO2) with an oximetry catheter. Mixed venous O2 saturation (SvO2) and cardiac output were also measured continuously with an oximetry pulmonary artery catheter. Systemic O2 delivery and V˙ O 2 were calculated according to accepted formulae. RESULTS: Immediately following extubation, ScvO2 and SvO2 decreased rapidly (P < .01). Systemic O2 consumption increased from 65 (57) mL·min-1 to 194 (66) mL·min-1 (P < .05) with no changes in DO2. Consequently, systemic O2 extraction rose from 38% (8%) to 45% (9%; P < .01). Preoperative left ventricular ejection fraction correlated with the decline in SvO2 postextubation. All patients weaned successfully. CONCLUSIONS: Decreases in SvO2 after discontinuation of ventilatory support in postcardiac surgery patients occur as V˙ O 2 increases in response to greater energy requirements by muscles of ventilation that are not initially matched by increases in DO2.


Assuntos
Extubação/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Consumo de Oxigênio , Oxigênio/sangue , Desmame do Respirador/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Gasometria , Débito Cardíaco , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oximetria , Período Pós-Operatório , Artéria Pulmonar , Respiração Artificial
8.
Biomed Eng Online ; 18(1): 45, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30991997

RESUMO

OBJECTIVES: Analyze the mechanics of Finochietto-style retractors, including the responses of thoracic tissues during thoracotomy, with an emphasis on tissue trauma and means for its reduction. METHODS: Mechanical analyses of the retractor were performed, including analysis of deformation under load and kinematics of the crank mechanism. Thoracotomies in a porcine model were performed in anesthetized animals (7) and fresh cadavers (17) using an instrumented retractor. RESULTS: Mechanical analyses revealed that arm motion is a non-linear function of handle rotation, that deformation of the retractor under load concentrates force at one edge of the retractor blade, and that the retractor behaves like a spring, deforming under the load of retraction and continuing to force open the incision long after crank rotation stops. Experimental thoracotomies included retractions ranging from 50 to 112 mm over 30 to 370 s, generating maximum forces of 118 to 470 N (12-50 kgf). Tissue ruptures occurred in 12 of the 24 retractions. These ruptures all occurred at retraction distances wider than 30 mm and at forces greater than 122.5 N. Significant tissue ruptures were observed for nearly all retractions at higher retraction rates (exceeding ½ rotation of the crank per 10 s). CONCLUSIONS: The Finochietto-style retractor can generate large forces and some aspects of its design increase the probability of tissue trauma.


Assuntos
Fenômenos Mecânicos , Toracotomia/instrumentação , Animais , Feminino , Suínos , Suporte de Carga
9.
J Sport Rehabil ; 28(4): 350-353, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29364033

RESUMO

Context: College soccer players suffer from hamstring injuries due to inflexibility and repetitive motions involving intense hamstring lengthening and contraction during sport. Although it is a popular intervention for muscular injury, there exists limited evidence of the effects of therapeutic cupping on hamstring flexibility. Objective: To determine the effect of cupping therapy on hamstring flexibility in college soccer players. Design: Cohort design. Setting: Athletic training clinic. Patients: A total of 25, asymptomatic, National Collegiate Athletic Association Division III soccer players (10 males and 15 females; age = 19.4 [1.30] y, height = 175.1 [8.2] cm, and mass = 69.5 [6.6] kg). Intervention(s): A 7-minute therapeutic cupping treatment was delivered to the treatment group. Four 2-in cups were fixed atop trigger point locations within the hamstring muscle bellies of participants' dominant legs. Control group participants received no intervention between pretest and posttest measurements. Main Outcome Measures: Pretest and posttest measurements of hamstring flexibility, using a passive straight leg raise, were performed on both groups. Passive straight leg raise measurements were conducted by blinded examiners using a digital inclinometer. An independent samples t test was used to analyze changes in hamstring flexibility from pretreatment to posttreatment with P values set a priori at .05. Results: An independent samples t test demonstrated no significant difference in change in hamstring flexibility between participants in the treatment group and those in the control group (t23 = -.961, P = .35). Conclusions: The findings of this study demonstrated no statistically significant changes in hamstring flexibility following a cupping treatment.


Assuntos
Terapias Complementares , Elasticidade , Músculos Isquiossurais/fisiologia , Traumatismos da Perna/prevenção & controle , Adolescente , Feminino , Humanos , Masculino , Músculo Esquelético/lesões , Futebol , Adulto Jovem
10.
J Virol ; 91(12)2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28356524

RESUMO

Membrane penetration by nonenveloped viruses remains enigmatic. In the case of the nonenveloped polyomavirus simian virus 40 (SV40), the virus penetrates the endoplasmic reticulum (ER) membrane to reach the cytosol and then traffics to the nucleus to cause infection. We previously demonstrated that the cytosolic Hsc70-SGTA-Hsp105 complex is tethered to the ER membrane, where Hsp105 and SGTA facilitate the extraction of SV40 from the ER and transport of the virus into the cytosol. We now find that Hsc70 also ejects SV40 from the ER into the cytosol in a step regulated by SGTA. Although SGTA's N-terminal domain, which mediates homodimerization and recruits cellular adaptors, is dispensable during ER-to-cytosol transport of SV40, this domain appears to exert an unexpected post-ER membrane translocation function during SV40 entry. Our study thus establishes a critical function of Hsc70 within the Hsc70-SGTA-Hsp105 complex in promoting SV40 ER-to-cytosol membrane penetration and unveils a role of SGTA in controlling this step.IMPORTANCE How a nonenveloped virus transports across a biological membrane to cause infection remains mysterious. One enigmatic step is whether host cytosolic components are co-opted to transport the viral particle into the cytosol. During ER-to-cytosol membrane transport of the nonenveloped polyomavirus SV40, a decisive infection step, a cytosolic complex composed of Hsc70-SGTA-Hsp105 was previously shown to associate with the ER membrane. SGTA and Hsp105 have been shown to extract SV40 from the ER and transport the virus into the cytosol. We demonstrate here a critical role of Hsc70 in SV40 ER-to-cytosol penetration and reveal how SGTA controls Hsc70 to impact this process.


Assuntos
Proteínas de Transporte/metabolismo , Citosol/virologia , Retículo Endoplasmático/virologia , Proteínas de Choque Térmico HSC70/metabolismo , Vírus 40 dos Símios/fisiologia , Internalização do Vírus , Animais , Transporte Biológico/fisiologia , Células COS , Proteínas de Transporte/genética , Linhagem Celular , Chlorocebus aethiops , Citosol/metabolismo , Retículo Endoplasmático/fisiologia , Regulação da Expressão Gênica , Células HEK293 , Proteínas de Choque Térmico HSC70/genética , Interações Hospedeiro-Patógeno/genética , Humanos , Membranas Intracelulares/virologia , Chaperonas Moleculares/metabolismo , RNA Interferente Pequeno
11.
PLoS Pathog ; 12(9): e1005914, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27685252

RESUMO

Hypochlorous acid (HOCl) is produced naturally by neutrophils and other cells to kill conventional microbes in vivo. Synthetic preparations containing HOCl can also be effective as microbial disinfectants. Here we have tested whether HOCl can also inactivate prions and other self-propagating protein amyloid seeds. Prions are deadly pathogens that are notoriously difficult to inactivate, and standard microbial disinfection protocols are often inadequate. Recommended treatments for prion decontamination include strongly basic (pH ≥~12) sodium hypochlorite bleach, ≥1 N sodium hydroxide, and/or prolonged autoclaving. These treatments are damaging and/or unsuitable for many clinical, agricultural and environmental applications. We have tested the anti-prion activity of a weakly acidic aqueous formulation of HOCl (BrioHOCl) that poses no apparent hazard to either users or many surfaces. For example, BrioHOCl can be applied directly to skin and mucous membranes and has been aerosolized to treat entire rooms without apparent deleterious effects. Here, we demonstrate that immersion in BrioHOCl can inactivate not only a range of target microbes, including spores of Bacillus subtilis, but also prions in tissue suspensions and on stainless steel. Real-time quaking-induced conversion (RT-QuIC) assays showed that BrioHOCl treatments eliminated all detectable prion seeding activity of human Creutzfeldt-Jakob disease, bovine spongiform encephalopathy, cervine chronic wasting disease, sheep scrapie and hamster scrapie; these findings indicated reductions of ≥103- to 106-fold. Transgenic mouse bioassays showed that all detectable hamster-adapted scrapie infectivity in brain homogenates or on steel wires was eliminated, representing reductions of ≥~105.75-fold and >104-fold, respectively. Inactivation of RT-QuIC seeding activity correlated with free chlorine concentration and higher order aggregation or destruction of proteins generally, including prion protein. BrioHOCl treatments had similar effects on amyloids composed of human α-synuclein and a fragment of human tau. These results indicate that HOCl can block the self-propagating activity of prions and other amyloids.

12.
Faraday Discuss ; 210(0): 29-39, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30046791

RESUMO

Photothermal heating at metal nanoparticles results from the non-radiative decay of localized surface plasmons. The local heat generation enhances the mass transport rate of redox molecules and causes a shift in their formal potential, both of which can impact an electrochemical process at the nanoparticle interface. Here we present a methodology for probing the surface temperature at a plasmonic nanoparticle substrate using scanning electrochemical microscopy (SECM). Light is used to excite a plasmonic substrate electrode, while an ultramicroelectrode tip is positioned close to the substrate to read out both the mass transfer rate and concentration profile of the redox molecules. The measured mass transfer rate and the shift in the equilibrium potential provide a quantitative value of the temperature increase at the substrate surface, which is verified by simulations using a mass transfer model coupled with heat dissipation. The developed SECM approach is suitable for probing heat generation at a variety of both plasmonic and non-plasmonic nanostructures.

13.
JAAPA ; 30(6): 22-25, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28538425

RESUMO

Hypokalemia can cause reactions from mild muscular cramping to life-threatening paralysis and cardiac dysrhythmias. This article describes a patient whose unusual, recurrent muscular symptoms and electrolyte abnormalities were eventually identified as Gitelman syndrome, a rare genetic disorder resulting in severe refractory hypokalemia.


Assuntos
Dor no Peito/etiologia , Síndrome de Gitelman/complicações , Síndrome de Gitelman/diagnóstico , Hipercalciúria/etiologia , Hipopotassemia/etiologia , Nefrocalcinose/etiologia , Paralisia/etiologia , Erros Inatos do Transporte Tubular Renal/etiologia , Adulto , Humanos , Masculino , Recidiva
14.
J Neurooncol ; 129(2): 281-8, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27311730

RESUMO

Meningiomas that progress after standard therapies are challenging with limited effective chemotherapy options. This phase II trial evaluated the efficacy of everolimus plus bevacizumab in patients with recurrent, progressive meningioma after treatment with surgical resection and local radiotherapy when appropriate. Patients with recurrent meningioma (WHO grade I, II, or III) following standard treatments with surgical resection and radiotherapy received bevacizumab (10 mg/kg IV days 1 and 15) and everolimus (10 mg PO daily) each 28 day cycle. Evaluation of response occurred every 2 cycles. The primary endpoint was progression-free survival (PFS). Secondary endpoints included response rate, overall survival and safety. Seventeen patients with a median age of 59 years (29-84) received study treatment. WHO grades at study entry included: I, 5 (29 %); II, 7 (41 %); III, 4 (24 %); unknown, 1 (6 %). Patients received a median of 8 cycles (1-37); all patients are off study treatment. A best response of SD was observed in 15 patients (88 %), and 6 patients had SD for >12 months. Overall median PFS was 22 months (95 % CI 4.5-26.8) and was greater for patients with WHO grade II and III compared to grade I tumors (22.0 months vs 17.5 months). Four patients discontinued treatment due to toxicity (proteinuria, 2; colitis, 1, thrombocytopenia, 1). However, other grade 3 toxicity was uncommon, and no patient had grade 4 toxicity. The combination of everolimus and bevacizumab was well-tolerated, and produced stable disease in 88 % of patients; the median duration of disease stabilization of 10 months (2-29). The median PFS from this prospective trial was similar to previous retrospective reports of bevacizumab in the treatment of recurrent meningioma.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Bevacizumab/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Everolimo/uso terapêutico , Imunossupressores/uso terapêutico , Meningioma/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/diagnóstico por imagem , Intervalo Livre de Doença , Feminino , Humanos , Injeções Intravenosas , Imageamento por Ressonância Magnética , Masculino , Meningioma/diagnóstico por imagem , Pessoa de Meia-Idade , Resultado do Tratamento
15.
Early Child Res Q ; 34: 128-139, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26941476

RESUMO

Caregiver responsiveness has been theorized and found to support children's early executive function (EF) development. This study examined the effects of an intervention that targeted family child care provider responsiveness on children's EF. Family child care providers were randomly assigned to one of two intervention groups or a control group. An intervention group that received a responsiveness-focused online professional development course and another intervention group that received this online course plus weekly mentoring were collapsed into one group because they did not differ on any of the outcome variables. Children (N = 141) ranged in age from 2.5 to 5 years (mean age = 3.58 years; 52% female). At pretest and posttest, children completed delay inhibition tasks (gift delay-wrap, gift delay-bow) and conflict EF tasks (bear/dragon, dimensional change card sort), and parents reported on the children's level of attention problems. Although there were no main effects of the intervention on children's EF, there were significant interactions between intervention status and child age for delay inhibition and attention problems. The youngest children improved in delay inhibition and attention problems if they were in the intervention rather than the control group, whereas older children did not. These results suggest that improving family child care provider responsive behaviors may facilitate the development of certain EF skills in young preschool-age children.

16.
J Cell Sci ; 126(Pt 22): 5247-58, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24046445

RESUMO

MrfA, a transcription factor that regulates Dictyostelium prestalk cell differentiation, is an orthologue of the metazoan myelin gene regulatory factor (MRF) proteins. We show that the MRFs contain a predicted transmembrane domain, suggesting that they are synthesised as membrane-tethered proteins that are then proteolytically released. We confirm this for MrfA but report a radically different mode of processing from that of paradigmatic tethered transcriptional regulators, which are cleaved within the transmembrane domain by a dedicated protease. Instead, an auto-proteolytic cleavage mechanism, previously only described for the intramolecular chaperone domains of bacteriophage tail-spike proteins, processes MrfA and, by implication, the metazoan MRF proteins. We also present evidence that the auto-proteolysis of MrfA occurs rapidly and constitutively in the ER and that its specific role in prestalk cell differentiation is conferred by the regulated nuclear translocation of the liberated fragment.


Assuntos
Dictyostelium/crescimento & desenvolvimento , Proteínas de Membrana/isolamento & purificação , Fatores de Transcrição/isolamento & purificação , Proteínas da Cauda Viral/genética , Sequência de Aminoácidos , Bacteriófagos/genética , Diferenciação Celular , Dictyostelium/genética , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Glicosídeo Hidrolases , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Chaperonas Moleculares/genética , Proteólise , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas da Cauda Viral/metabolismo
17.
J Exp Child Psychol ; 132: 14-31, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25576967

RESUMO

This study examined the concurrent and longitudinal associations of parental responsiveness and inferential language input with cognitive skills and emotion knowledge among socioeconomically disadvantaged preschoolers. Parents and 2- to 4-year-old children (mean age=3.21 years, N=284) participated in a parent-child free play session, and children completed cognitive (language, early literacy, early mathematics) and emotion knowledge assessments. Approximately 1 year later, children completed the same assessment battery. Parental responsiveness was coded from the videotaped parent-child free play sessions, and parental inferential language input was coded from transcripts of a subset of 127 of these sessions. All analyses controlled for child age, gender, and parental education, and longitudinal analyses controlled for initial skill level. Parental responsiveness significantly predicted all concurrent cognitive skills as well as literacy, math, and emotion knowledge 1 year later. Parental inferential language input was significantly positively associated with children's concurrent emotion knowledge. In longitudinal analyses, an interaction was found such that for children with stronger initial language skills, higher levels of parental inferential language input facilitated greater vocabulary development, whereas for children with weaker initial language skills, there was no association between parental inferential language input and change in children's vocabulary skills. These findings further our understanding of the roles of parental responsiveness and inferential language input in promoting children's school readiness skills.


Assuntos
Aptidão/fisiologia , Linguagem Infantil , Cognição/fisiologia , Emoções/fisiologia , Poder Familiar/psicologia , Pobreza/psicologia , Desenvolvimento Infantil , Pré-Escolar , Feminino , Humanos , Estudos Longitudinais , Masculino , Pobreza/estatística & dados numéricos , Fatores Socioeconômicos , Populações Vulneráveis/psicologia , Populações Vulneráveis/estatística & dados numéricos
18.
Proc Natl Acad Sci U S A ; 109(28): E1931-7, 2012 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-22699506

RESUMO

SH2 domains are integral to many animal signaling pathways. By interacting with specific phosphotyrosine residues, they provide regulatable protein-protein interaction domains. Dictyostelium is the only nonmetazoan with functionally characterized SH2 domains, but the cognate tyrosine kinases are unknown. There are no orthologs of the animal tyrosine kinases, but there are very many tyrosine kinase-like kinases (TKLs), a group of kinases which, despite their family name, are classified mainly as serine-threonine kinases. STATs are transcription factors that dimerize via phosphotyrosine-SH2 domain interactions. STATc is activated by phosphorylation on Tyr922 when cells are exposed to the prestalk inducer differentiation inducing factor (DIF-1), a chlorinated hexaphenone. We show that in a null mutant for Pyk2, a tyrosine-specific TKL, exposure to DIF-1 does not activate STATc. Conversely, overexpression of Pyk2 causes constitutive STATc activation. Pyk2 phosphorylates STATc on Tyr922 in vitro and complexes with STATc both in vitro and in vivo. This demonstration that a TKL directly activates a STAT has significant implications for understanding the evolutionary origins of SH2 domain-phosphotyrosine signaling. It also has mechanistic implications. Our previous work suggested that a predicted constitutive STATc tyrosine kinase activity is counterbalanced in vivo by the DIF-1-regulated activity of PTP3, a Tyr922 phosphatase. Here we show that the STATc-Pyk2 complex is formed constitutively by an interaction between the STATc SH2 domain and phosphotyrosine residues on Pyk2 that are generated by autophosphorylation. Also, as predicted, Pyk2 is constitutively active as a STATc kinase. This observation provides further evidence for this highly atypical, possibly ancestral, STAT regulation mechanism.


Assuntos
Dictyostelium/metabolismo , Quinase 2 de Adesão Focal/genética , Hexanonas/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/fisiologia , Fatores de Transcrição STAT/genética , Fatores de Transcrição STAT/fisiologia , Domínios de Homologia de src/genética , Evolução Molecular , Quinase 2 de Adesão Focal/metabolismo , Glutationa Transferase/metabolismo , Modelos Biológicos , Mutação , Fosforilação , Ligação Proteica , Mapeamento de Interação de Proteínas/métodos , Proteínas Tirosina Quinases/metabolismo , Tirosina/química
19.
J Exp Child Psychol ; 119: 1-16, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24269579

RESUMO

Longitudinal studies of neurodevelopmental disorders that are diagnosed at or before birth and are associated with specific learning difficulties at school-age provide one method for investigating developmental precursors of later-emerging academic disabilities. Spina bifida myelomeningocele (SBM) is a neurodevelopmental disorder associated with particular problems in mathematics, in contrast to well-developed word reading. Children with SBM (n=30) and typically developing children (n=35) were used to determine whether cognitive abilities measured at 36 and 60 months of age mediated the effect of group on mathematical and reading achievement outcomes at 8.5 and 9.5 years of age. A series of multiple mediator models showed that: visual-spatial working memory at 36 months and phonological awareness at 60 months partially mediated the effect of group on math calculations, phonological awareness partially mediated the effect of group on small addition and subtraction problems on a test of math fluency, and visual-spatial working memory mediated the effect of group on a test of math problem solving. Groups did not differ on word reading, and phonological awareness was the only mediator for reading fluency and reading comprehension. The findings are discussed with reference to theories of mathematical development and disability and with respect to both common and differing cognitive correlates of math and reading.


Assuntos
Logro , Desenvolvimento Infantil/fisiologia , Deficiências do Desenvolvimento/complicações , Matemática , Leitura , Disrafismo Espinal/complicações , Análise de Variância , Criança , Pré-Escolar , Cognição/fisiologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Memória de Curto Prazo/fisiologia , Testes Neuropsicológicos/estatística & dados numéricos , Fonética , Resolução de Problemas/fisiologia
20.
J AOAC Int ; 97(6): 1626-33, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25230794

RESUMO

With the recent adoption of a DNA sequencing-based method for the species identification for seafood products by the U.S. Food and Drug Administration (FDA), a library of standard sequences derived from reference specimens with authoritative taxonomic authentication was required. Provided here are details of how the FDA and its collaborators are building this reference standard sequence library that will be used to confirm the accurate labeling of seafood products sold in interstate commerce in the United States. As an example data set from this library, information for 117 fish reference standards, representing 94 species from 43 families in 15 orders, collected over a 4-year period from the Gulf of Mexico, U.S., that are now stored at the Smithsonian Museum Support Center in Suitland, MD, are provided.


Assuntos
DNA/genética , Peixes/genética , Biblioteca Gênica , Alimentos Marinhos/análise , Alimentos Marinhos/normas , Animais , Sequência de Bases , Dados de Sequência Molecular , Padrões de Referência
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