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1.
Ecol Food Nutr ; 61(2): 162-181, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34468242

RESUMEN

Anthropologists have long emphasized the social significance of foods and the contexts in which they are consumed. Expanding on this idea, we define the context of consumption as the non-eating behaviors that surround eating, such as the manner of food preparation, food sharing, and dietary patterns. In this study, we used cultural consensus analysis to assess whether there exist consistently shared, normative ideas about preferable context of food consumption in three diverse research sites: urban Ethiopia, rural Brazil, and rural Haiti. Our analysis demonstrates that in all three communities, there are distinct sets of behaviors that people identified as non-preferable because they reliably associate them with poverty and food insecurity, and behaviors that people identify as preferable because they reliably associate them with wealth and food security. Across the settings, there was little variation in agreement about behaviors across household composition, age, gender, and food security status. These findings suggest that people do indeed share culturally specific ideas about the context in which foods should be prepared and consumed, beyond the actual content of one's diet. Exploring these cultural models elucidates the social consequences of food insecurity, enabling researchers to better examine the relationship between food insecurity, social context, and well-being.


Asunto(s)
Abastecimiento de Alimentos , Población Rural , Dieta , Seguridad Alimentaria , Humanos , Pobreza
2.
Opt Express ; 29(5): 7858-7865, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33726279

RESUMEN

Spatial optical Fourier filtering is a widespread technique for in situ image or light field processing. However, conventional fixed absorbing patterns or mechanical irises only allow an inflexible, very restricted control. Thus, we present two electrochromic spatial filters with ring-shaped or directional segments, which can be individually addressed and continuously tuned in transmission resulting in up to 512 different filtering states. For realization of the electrochromic devices, we overcome technical obstacles to realize seamless, gap-free electrochromic segments. We describe this novel fabrication process and demonstrate the successful application in an optical Fourier transform set-up.

3.
J Synchrotron Radiat ; 26(Pt 1): 263-271, 2019 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-30655494

RESUMEN

GALAXIES is an in-vacuum undulator hard X-ray micro-focused beamline dedicated to the study of the electronic structure of materials with high energy resolution using both photoelectron spectroscopy and inelastic X-ray scattering and under both non-resonant (NR-IXS) and resonant (RIXS) conditions. Due to the penetrating power of hard X-rays and the `photon-in/photon-out' technique, the sample environment is not a limitation. Materials under extreme conditions, for example in diamond anvil cells or catalysis chambers, thus constitute a major research direction. Here, the design and performance of the inelastic X-ray scattering end-station that operates in the energy range from ∼4 keV up to 12 keV is reported, and its capabilities are highlighted using a selection of data taken from recently performed experiments. The ability to scan `on the fly' the incident and scattered/emitted X-ray energies, and the sample position enables fast data collection and high experimental throughput. A diamond X-ray transmission phase retarder, which can be used to generate circularly polarized light, will also be discussed in the light of the recent RIXS-MCD approach.

4.
J Appl Microbiol ; 124(5): 1092-1106, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29356220

RESUMEN

AIMS: We evaluated the effects of Bacillus anthracis surrogates, low surface concentrations, surface materials and assay methods on false-negative rate (FNR) and limit of detection (LOD95 ) for recovering Bacillus spores using a macrofoam-swab sampling procedure. METHODS AND RESULTS: Bacillus anthracis Sterne or Bacillus atrophaeus Nakamura spores were deposited over a range of low target concentrations (2-500 per coupon) onto glass, stainless steel, vinyl tile and plastic. Samples were assayed using a modified Rapid Viability-PCR (mRV-PCR) method and the traditional plate culture method to obtain FNR and LOD95 results. CONCLUSIONS: Mean FNRs tended to be lower for mRV-PCR compared to culturing, and increased as spore concentration decreased for all surface materials. Surface material, but not B. anthracis surrogate, influenced FNRs with the mRV-PCR method. The mRV-PCR LOD95 was lowest for glass and highest for vinyl tile. LOD95 values overall were lower for mRV-PCR than for the culture method. SIGNIFICANCE AND IMPACT OF STUDY: This study adds to the limited data on FNR and LOD95 for mRV-PCR and culturing methods with low concentrations of B. anthracis sampled from various surface materials by the CDC macrofoam-swab method. These are key inputs for planning characterization and clearance studies for low contamination levels of B. anthracis.


Asunto(s)
Bacillus anthracis/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Bacillus/genética , Bacillus/aislamiento & purificación , Bacillus anthracis/genética , Técnicas Bacteriológicas , Límite de Detección , Esporas Bacterianas/genética , Esporas Bacterianas/aislamiento & purificación
5.
Analyst ; 143(1): 123-132, 2017 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-29165439

RESUMEN

The process of sporulation is vital for the stability and infectious cycle of Bacillus anthracis. The spore is the infectious form of the organism and therefore relevant to biodefense. While the morphological and molecular events occurring during sporulation have been well studied, the influence of growth medium and temperature on the proteins expressed in sporulated cultures is not well understood. Understanding the features of B. anthracis sporulation specific to natural vs. laboratory production will address an important question in microbial forensics. In an effort to bridge this knowledge gap, a system for sporulation on two types of agar-immobilized soils was used for comparison to cultures sporulated on two common types of solid laboratory media, and one liquid sporulation medium. The total number of proteins identified as well as their identity differed between samples generated in each medium and growth temperature, demonstrating that sporulation environment significantly impacts the protein content of the spore. In addition, a subset of proteins common in all of the soil-cultivated samples was distinct from the expression profiles in laboratory medium (and vice versa). These differences included proteins involved in thiamine and phosphate metabolism in the sporulated cultures produced on soils with a notable increase in expression of ATP binding cassette (ABC) transporters annotated to be for phosphate and antimicrobial peptides. A distinct set of ABC transporters for amino acids, sugars and oligopeptides were found in cultures produced on laboratory media as well as increases in carbon and amino acid metabolism-related proteins. These protein expression changes indicate that the sporulation environment impacts the protein profiles in specific ways that are reflected in the metabolic and membrane transporter proteins present in sporulated cultures.


Asunto(s)
Bacillus anthracis/química , Bacillus anthracis/fisiología , Proteómica , Suelo , Esporas Bacterianas/química , Medios de Cultivo , Esporas Bacterianas/fisiología
6.
J Appl Microbiol ; 121(1): 149-62, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26972788

RESUMEN

AIMS: We sought to evaluate the effects of Bacillus species, low surface concentrations, and surface material on recovery efficiency (RE), false-negative rate (FNR) and limit of detection for recovering Bacillus spores using a validated macrofoam-swab sampling procedure. METHODS AND RESULTS: The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target surface concentrations (2 to 500 CFU per plate or coupon) to positive-control plates and test coupons (25·8064 cm(2) ) of four surface materials (glass, stainless steel, vinyl tile and plastic). The Bacillus species and surface material had statistically significant effects on RE, but surface concentration did not. Mean REs were the lowest for vinyl tile (50·8% with BAS and 40·2% with BG) and the highest for glass (92·8% with BAS and 71·4% with BG). FNR values (which ranged from 0 to 0·833 for BAS and from 0 to 0·806 for BG) increased as surface concentration decreased in the range tested. Surface material also had a statistically significant effect on FNR, with FNR the lowest for glass and highest for vinyl tile. Finally, FNR tended to be higher for BG than for BAS at lower surface concentrations, especially for glass. CONCLUSIONS: Concentration and surface material had significant effects on FNR, with Bacillus species having a small effect. Species and surface material had significant effects on RE, with surface concentration having a nonsignificant effect. SIGNIFICANCE AND IMPACT OF THE STUDY: The results provide valuable information on the performance of the macrofoam-swab method for low surface concentrations of Bacillus spores, which can be adapted to assess the likelihood that there is no contamination when all macrofoam-swab samples fail to detect B. anthracis.


Asunto(s)
Bacillus anthracis/aislamiento & purificación , Bacillus/aislamiento & purificación , Técnicas Microbiológicas/métodos , Esporas Bacterianas/aislamiento & purificación , Bacillus/clasificación , Bacillus anthracis/crecimiento & desarrollo , Límite de Detección , Técnicas Microbiológicas/instrumentación , Técnicas Microbiológicas/normas , Esporas Bacterianas/crecimiento & desarrollo , Acero Inoxidable/análisis
7.
J Synchrotron Radiat ; 22(1): 175-9, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25537606

RESUMEN

The GALAXIES beamline at the SOLEIL synchrotron is dedicated to inelastic X-ray scattering (IXS) and photoelectron spectroscopy (HAXPES) in the 2.3-12 keV hard X-ray range. These two techniques offer powerful complementary methods of characterization of materials with bulk sensitivity, chemical and orbital selectivity, resonant enhancement and high resolving power. After a description of the beamline components and endstations, the beamline capabilities are demonstrated through a selection of recent works both in the solid and gas phases and using either IXS or HAXPES approaches. Prospects for studies on liquids are discussed.

8.
Phys Chem Chem Phys ; 16(24): 12043-50, 2014 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-24710175

RESUMEN

A photovoltaic tandem cell made of amorphous silicon (a-Si) and microcrystalline silicon (µc-Si) was investigated as a photocathode for hydrogen evolution in a photoelectrochemical device. The electronic and electrochemical properties of the samples were characterized using X-ray photoemission spectroscopy (XPS) and cyclic voltammetry (CV), whereas the morphology of the surface in contact with the electrolyte was investigated by scanning electron microscopy (SEM). The electric efficiency of the tandem cell was determined to be 5.2% in a photoelectrochemical (PEC) setup in acidic solution which is only about half of the photovoltaic efficiency of the tandem cell. A significant improvement in efficiency was achieved with platinum as a catalyst which was deposited by physical vapour deposition (PVD) under ultra-high vacuum (UHV) conditions.

9.
Rev Epidemiol Sante Publique ; 61(6): 513-8, 2013 Dec.
Artículo en Francés | MEDLINE | ID: mdl-24206904

RESUMEN

BACKGROUND: School vaccination programs against human papilloma virus (HPV) have been implemented in most Western countries. Only a few studies have investigated socio-economic factors related to school-based vaccination. METHOD: A cross-sectional study was conducted using the vaccination cards of 1158 randomized girls aged 13 to 14 years enrolled in the public schools of the canton of Geneva. Several other socio-economic variables (nationality, socio-professional category and marital status of the parents) were collected. RESULTS: Immunization coverage for three doses of HPV vaccine was 56%. After having controlled the covariates, Portuguese adolescents (adjusted OR [95% CI]: 4.18 [1.76-9.92]), adolescents whose mothers were workers (adjusted OR [95% CI]: 1.91 [1.38-2.65]) or married (adjusted OR [95% CI]: 1.44 [1.06-1.98]) showed significantly higher immunization rates than Swiss adolescents or those whose mothers' socio-professional category was senior manager or executive. CONCLUSION: This study shows that the HPV vaccine coverage is not yet optimal in Geneva and varies significantly according to the socio-economic status, thus better promotion of HPV vaccination for certain target groups must be implemented.


Asunto(s)
Infecciones por Papillomavirus/prevención & control , Vacunas contra Papillomavirus/administración & dosificación , Neoplasias del Cuello Uterino/prevención & control , Vacunación/estadística & datos numéricos , Adolescente , Ciudades/epidemiología , Estudios Transversales , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Infecciones por Papillomavirus/epidemiología , Aceptación de la Atención de Salud/estadística & datos numéricos , Instituciones Académicas/estadística & datos numéricos , Factores Socioeconómicos , Suiza/epidemiología , Neoplasias del Cuello Uterino/epidemiología
10.
Plant Biol (Stuttg) ; 25(4): 498-508, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36992539

RESUMEN

The cyanogenic glucoside, dhurrin, present in Sorghum bicolor is thought to have multiple functions, including in defence against herbivory. The hormone methyl jasmonate (MeJA) is also induced by herbivory and is key to instigating defence processes in plants. To investigate whether dhurrin is induced in response to herbivore attack and also to the associated presence of MeJA, sorghum plants were either wounded or exogenous MeJA was applied. We show that specific wounding (pin board and perforation) and the application of MeJA increases dhurrin concentration in leaves and sheath tissue 12 h after treatment. Quantitative PCR shows that the expression of two genes, SbCYP79A1 and SbUGT85B1, involved in the synthesis of dhurrin are significantly induced by exogenous MeJA and by wounding. Analysis of 2 kb of sequence upstream of the start codon of SbCYP79A1 identifies several cis-acting elements that have been linked to MeJA induction. A promoter deletion series, coupled to GFP, and transiently expressed in Nicotiana benthamiana suggests that there are potentially three sequence motifs (~-925 to -976) involved in the binding of transcription factors that result in increased expression of SbCYP79A1 and the synthesis of dhurrin in response to MeJA.


Asunto(s)
Sorghum , Sorghum/genética , Sorghum/metabolismo , Regulación hacia Arriba , Plantas , Ciclopentanos/farmacología , Ciclopentanos/metabolismo , Oxilipinas/farmacología , Oxilipinas/metabolismo , Glucósidos , Acetatos/farmacología
11.
Nervenarzt ; 83(6): 741-50, 2012 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-22669125

RESUMEN

OBJECTIVE: This study characterized artificially ventilated patients in a neurological intensive care unit (NICU) between 2006-2008 in a purely neurological clinic and a so-called stand-alone situation. In addition the long-term prognoses as well as the quality of life of surviving patients were investigated. METHODS: All ventilated patients from October 2006 to December 2008 were enrolled in this descriptive, retrospective study. The duration of stay in intensive care was analyzed and the current quality of life was prospectively assessed based on the patient records. Final diagnoses, duration of intensive care unit and ventilation as well as the highest score in SAPS II (simplified acute physiology score) and complications during hospitalization were determined. The patients were divided into groups based on the diagnoses as vascular, inflammatory, neurodegenerative, hereditary, epileptogenic and others. Additionally patients were contacted and asked to respond by completing questionnaires on the Barthel index (BI) and the modified Rankin scale (mRS). RESULTS: During the study period a total of 512 patients were treated in the NICU of whom 201 required artificial respiration. Cerebrovascular diseases were the main reason for therapy in the NICU in 96 out of 201 cases (47.8%), followed by inflammatory diseases in 46 (22.8%) and epileptogenic diseases in 26 patients (13%). The median duration of artificial respiration was 9 days with a mean treatment duration of 16 days (range 1-57 days). Of the patients 31 (15.4%) died in the NICU and an additional 32 patients (18.8%) died within a median of 2 months after discharge. Outcome data were available from 67 out of 170 sent questionnaires and rehabilitation reports of 86 patients, which enabled the outcome of 121 surviving patients to be analyzed (71.2%). Of these 42.2% showed no or mild impairment in everyday life. However, the remaining 38% had severe impairments according to the BI. The evaluation of the mRS showed that 49.6% of the patients still had severe symptoms. CONCLUSIONS: More than one third of the patients treated in the NICU required artificial ventilation with an emphasis on cerebrovascular diseases, which illustrates the overlap between stroke unit and NICU care. Despite a lengthy duration of ventilation and a long stay in the intensive care unit more than one third of surviving patients showed no or only mild impairment. However, an additional third suffered from severe disability up to nursing care dependency. The study data differ little from the few publications in this field despite the stand alone situation of the NICU. The case mix index per day averaged around 0.3 and underlines the economic importance with respect to other forms of neurological treatment.


Asunto(s)
Trastornos Cerebrovasculares/mortalidad , Trastornos Cerebrovasculares/rehabilitación , Unidades de Cuidados Intensivos/estadística & datos numéricos , Neurología/estadística & datos numéricos , Calidad de Vida , Respiración Artificial/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Alemania/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Medición de Riesgo , Análisis de Supervivencia , Tasa de Supervivencia , Resultado del Tratamiento
12.
Nat Cell Biol ; 3(8): 715-22, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11483956

RESUMEN

To ensure proper timing of the G1-S transition in the cell cycle, the cyclin E-Cdk2 complex, which is responsible for the initiation of DNA replication, is restrained by the p21(Cip1)/p27(Kip1)/p57(Kip2) family of CDK (cyclin-dependent kinase) inhibitors in humans and by the related p27(Xic1) protein in Xenopus. Activation of cyclin E-Cdk2 is linked to the ubiquitination of human p27(Kip1) or Xenopus p27(Xic1) by SCF (for Skp1-Cullin-F-box protein) ubiquitin ligases. For human p27(Kip1), ubiquitination requires direct phosphorylation by cyclin E-Cdk2. We show here that Xic1 ubiquitination does not require phosphorylation by cyclin E-Cdk2, but it does require nuclear accumulation of the Xic1-cyclin E-Cdk2 complex and recruitment of this complex to chromatin by the origin-recognition complex together with Cdc6 replication preinitiation factors; it also requires an activation step necessitating cyclin E-Cdk2-kinase and SCF ubiquitin-ligase activity, and additional factors associated with mini-chromosome maintenance proteins, including the inactivation of geminin. Components of the SCF ubiquitin-ligase complex, including Skp1 and Cul1, are also recruited to chromatin through cyclin E-Cdk2 and the preinitiation complex. Thus, activation of the cyclin E-Cdk2 kinase and ubiquitin-dependent destruction of its inhibitor are spatially constrained to the site of a properly assembled preinitiation complex.


Asunto(s)
Quinasas CDC2-CDC28 , Proteínas de Unión al Calcio , Proteínas de Ciclo Celular/metabolismo , Ciclo Celular/fisiología , Proteínas Cullin , Ciclina E/metabolismo , Quinasas Ciclina-Dependientes/metabolismo , Replicación del ADN/fisiología , Proteínas Nucleares , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Supresoras de Tumor , Ubiquitinas/metabolismo , Proteínas de Xenopus , Animales , Proteínas Portadoras , Proteínas de Ciclo Celular/genética , Cromatina/genética , Cromatina/metabolismo , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Ciclina E/genética , Quinasa 2 Dependiente de la Ciclina , Inhibidor p27 de las Quinasas Dependientes de la Ciclina , Quinasas Ciclina-Dependientes/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila , Embrión no Mamífero/citología , Embrión no Mamífero/metabolismo , Femenino , Ligasas/genética , Ligasas/metabolismo , Oocitos/citología , Oocitos/metabolismo , Complejo de Reconocimiento del Origen , Péptido Hidrolasas/genética , Péptido Hidrolasas/metabolismo , Péptido Sintasas/genética , Péptido Sintasas/metabolismo , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Proteínas Quinasas Asociadas a Fase-S , Proteínas Ligasas SKP Cullina F-box , Ubiquitina-Proteína Ligasas , Ubiquitinas/genética , Xenopus laevis
13.
Science ; 371(6525): 168-172, 2021 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-33335019

RESUMEN

Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the systems formed, which is analogous to how meteorite abundances inform our understanding of the early Solar System. We report the detection of lithium, sodium, potassium, and calcium in the atmosphere of the white dwarf Gaia DR2 4353607450860305024, which we ascribe to the accretion of a planetesimal. Using model atmospheres, we determine abundance ratios of these elements, and, with the exception of lithium, they are consistent with meteoritic values in the Solar System. We compare the measured lithium abundance with measurements in old stars and with expectations from Big Bang nucleosynthesis.

14.
Encephale ; 36(1): 54-61, 2010 Feb.
Artículo en Francés | MEDLINE | ID: mdl-20159197

RESUMEN

AIM OF THE STUDY: The aim of the present study is to explore the validity of the Padua inventory and two belief questionnaires: the obsessive beliefs questionnaire (OBQ) and the interpretation of intrusions inventory (III). BACKGROUND: The Padua inventory is a 60-item self-report measurement of obsessive compulsive symptoms that measures both classic compulsive checking and cleaning behaviour as well as various types of obsessions, including impulses. Studies in several countries have provided support for the reliability and validity of the Padua inventory, including Italy, the Netherlands, North America, and the UK. The obsessive beliefs questionnaire assesses belief domains related to obsessive compulsive disorder (OCD): inflated responsibility, importance of thoughts, control of thoughts, overestimation of threat, perfectionism, and intolerance of uncertainty. It consists of 87 items representing dysfunctional assumptions covering these six domains. The interpretation of intrusions inventory consists of 31 items that refer to interpretations of intrusions that have occurred recently. Three of the above domains are represented: importance of thoughts, control of thoughts and responsibility. Data from clinical or non-clinical samples are used to study the factor structure, reliability, and convergent and divergent validity of these two questionnaires. METHODOLOGY: The three questionnaires were administrated to two groups of people as follows: 96 patients with OCD and 53 non-clinical subjects. The patients were selected from Rhone Alpes clinics and hospitals using DSM-IV criteria for diagnosis, prior to treatment. Diagnosis was based on semi-structured interview (MINI) and clinical interview by a trained psychiatrist using DSM-IV criteria. The second aim of the study was to investigate generality and congruence criterion of the subscales of the Padua inventory and beliefs domains in OCD symptom subtypes (rumination, washing, checking). The present study investigates whether specific OCD symptom subtypes are associated with specific symptom subscales and belief domains in an OCD sample. The criteria for categorizing a participant into an OCD symptom subtype was a score greater or equal to 75% of one main ritual. Fifty participants (52%) met these criteria: washing (n=20), rumination (n=16), checking (n=8), hoarding (n=1), perfectionism (n=3), and repeating (n=2). The other 46 subjects formed a non-specific symptom subtype (two or more rituals). Participants in the precision (perfectionism), the hoarding, and repeating symptom subtypes were excluded because of a small sample. RESULTS: The Padua inventory and the two questionnaires OBQ and III discriminated between French OCD and non clinical controls. In the OCD sample, the three subtypes (washers, rumination and checkers) did not differ from each other on total YBOCS score and total Padua score. The "washer" subjects scored higher than both "checker" subjects and subjects with rumination on the washing scale of the Padua inventory. The "checker" subjects scored higher than the two other subtypes on the checking scale. The impaired mental control and urges and worries of losing control scales failed to discriminate between the subjects with rumination and the two other (checking and washing) subtypes. The OBQ total and the six subscale scores failed to discriminate between the three OCD subtypes. These results were replicated with the III. The ANOVAs revealed that the participants in the rumination symptom subtype scored higher only on the importance/control of thoughts of the OBQ-44 than the participants in the checking subtype. Implications for future research are discussed.


Asunto(s)
Cultura , Trastorno Obsesivo Compulsivo/diagnóstico , Trastorno Obsesivo Compulsivo/psicología , Adulto , Femenino , Francia , Humanos , Individualidad , Entrevista Psicológica , Masculino , Persona de Mediana Edad , Trastorno Obsesivo Compulsivo/clasificación , Inventario de Personalidad/estadística & datos numéricos , Psicometría/estadística & datos numéricos , Reproducibilidad de los Resultados , Adulto Joven
15.
Trends Cell Biol ; 10(10): 429-39, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10998601

RESUMEN

Recently, many new examples of E3 ubiquitin ligases or E3 enzymes have been found to regulate a host of cellular processes. These E3 enzymes direct the formation of multiubiquitin chains on specific protein substrates, and - typically - the subsequent destruction of those proteins. We discuss how the modular architecture of E3 enzymes connects one of two distinct classes of catalytic domains to a wide range of substrate-binding domains. In one catalytic class, a HECT domain transfers ubiquitin directly to substrate bound to a non-catalytic domain. Members of the other catalytic class, found in the SCF, VBC and APC complexes, use a RING finger domain to facilitate ubiquitylation. The separable substrate-recognition domains of E3 enzymes provides a flexible means of linking a conserved ubiquitylation function to potentially thousands of ubiquitylated substrates in eukaryotic cells.


Asunto(s)
Ligasas/metabolismo , Animales , Dominio Catalítico , Células Eucariotas/enzimología , Humanos , Ligasas/química , Especificidad por Sustrato/fisiología , Ubiquitina-Proteína Ligasas
16.
J Cell Biol ; 152(6): 1267-78, 2001 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-11257126

RESUMEN

Using an in vitro chromatin assembly assay in Xenopus egg extract, we show that cyclin E binds specifically and saturably to chromatin in three phases. In the first phase, the origin recognition complex and Cdc6 prereplication proteins, but not the minichromosome maintenance complex, are necessary and biochemically sufficient for ATP-dependent binding of cyclin E--Cdk2 to DNA. We find that cyclin E binds the NH(2)-terminal region of Cdc6 containing Cy--Arg-X-Leu (RXL) motifs. Cyclin E proteins with mutated substrate selection (Met-Arg-Ala-Ile-Leu; MRAIL) motifs fail to bind Cdc6, fail to compete with endogenous cyclin E--Cdk2 for chromatin binding, and fail to rescue replication in cyclin E--depleted extracts. Cdc6 proteins with mutations in the three consensus RXL motifs are quantitatively deficient for cyclin E binding and for rescuing replication in Cdc6-depleted extracts. Thus, the cyclin E--Cdc6 interaction that localizes the Cdk2 complex to chromatin is important for DNA replication. During the second phase, cyclin E--Cdk2 accumulates on chromatin, dependent on polymerase activity. In the third phase, cyclin E is phosphorylated, and the cyclin E--Cdk2 complex is displaced from chromatin in mitosis. In vitro, mitogen-activated protein kinase and especially cyclin B--Cdc2, but not the polo-like kinase 1, remove cyclin E--Cdk2 from chromatin. Rebinding of hyperphosphorylated cyclin E--Cdk2 to interphase chromatin requires dephosphorylation, and the Cdk kinase-directed Cdc14 phosphatase is sufficient for this dephosphorylation in vitro. These three phases of cyclin E association with chromatin may facilitate the diverse activities of cyclin E--Cdk2 in initiating replication, blocking rereplication, and allowing resetting of origins after mitosis.


Asunto(s)
Quinasas CDC2-CDC28 , Proteínas de Ciclo Celular/metabolismo , Ciclo Celular/fisiología , Cromatina/metabolismo , Ciclina E/metabolismo , Replicación del ADN/fisiología , Proteínas de Unión al ADN/metabolismo , Oocitos/fisiología , Proteínas Tirosina Fosfatasas , Proteínas de Saccharomyces cerevisiae , Secuencias de Aminoácidos , Animales , Western Blotting , Proteínas de Ciclo Celular/genética , Quinasa 2 Dependiente de la Ciclina , Quinasas Ciclina-Dependientes/metabolismo , Replicación del ADN/efectos de los fármacos , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/aislamiento & purificación , Humanos , Masculino , Modelos Biológicos , Oocitos/química , Complejo de Reconocimiento del Origen , Fosforilación , Unión Proteica , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Espermatozoides/citología , Espermatozoides/fisiología , Proteínas de Xenopus , Xenopus laevis
17.
Science ; 281(5380): 1202-6, 1998 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-9712587

RESUMEN

Nitrogen-fixing bacteroids in legume root nodules are surrounded by the plant-derived peribacteroid membrane, which controls nutrient transfer between the symbionts. A nodule complementary DNA (GmSAT1) encoding an ammonium transporter has been isolated from soybean. GmSAT1 is preferentially transcribed in nodules and immunoblotting indicates that GmSAT1 is located on the peribacteroid membrane. [14C]methylammonium uptake and patch-clamp analysis of yeast expressing GmSAT1 demonstrated that it shares properties with a soybean peribacteroid membrane NH4+ channel described elsewhere. GmSAT1 is likely to be involved in the transfer of fixed nitrogen from the bacteroid to the host.


Asunto(s)
Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Proteínas de Transporte de Catión , Glycine max/genética , Compuestos de Amonio Cuaternario/metabolismo , Proteínas de Soja , Secuencia de Aminoácidos , Secuencia de Bases , Transporte Biológico , Proteínas Portadoras/química , Membrana Celular/metabolismo , ADN Complementario , Canales Iónicos/metabolismo , Cinética , Metilaminas/metabolismo , Datos de Secuencia Molecular , Orgánulos/metabolismo , Técnicas de Placa-Clamp , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Potasio/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Glycine max/química , Glycine max/metabolismo , Glycine max/microbiología , Esferoplastos/metabolismo , Simbiosis , Transformación Genética
18.
Artículo en Inglés | MEDLINE | ID: mdl-31143467

RESUMEN

BACKGROUND: Psychiatric diagnostic manuals recognise the importance of local expressions of distress in culturally diverse settings [i.e. idioms/cultural concepts of distress (CCDs)], yet there is a lack of consensus on how these should be incorporated into mental health related research. AIMS: To perform a narrative synthesis and critical review of research exploring how idioms/CCDs have been integrated into assessment measures and interventions. METHOD: A systematic review was conducted in accordance with PRISMA guidelines. An adapted version of the COSMIN checklist was used to assess the quality of the linguistic translation of the idioms/CCDs. RESULTS: Twenty-nine papers were included in the final review. Primary qualitative research was the most common method of gathering information about idioms/CCDs. The majority of studies described integrating idioms/CCDs into assessment measures as opposed to interventions. Some studies used information relating to idioms/CCDs to develop novel assessment measures, while others adapted pre-existing assessment measures. The measures generated moderate to high levels of validity. Information relating to the linguistic translation conducted in the completion of the studies tended to be inadequately reported. CONCLUSIONS: Integrating information about idioms/CCDs into assessment measures can enhance the validity of these assessments. Allocating greater research attention to idioms/CCDs can also promote more equitable exchanges of knowledge about mental health and wellbeing between the Global North and the Global South.

19.
Artículo en Inglés | MEDLINE | ID: mdl-31258924

RESUMEN

BACKGROUND: The Boko Haram insurgency has brought turmoil and instability to Nigeria, generating a large number of internally displaced people and adding to the country's 17.5 million orphans and vulnerable children. Recently, steps have been taken to improve the mental healthcare infrastructure in Nigeria, including revamping national policies and initiating training of primary care providers in mental healthcare. In order for these efforts to succeed, they require means for community-based detection and linkage to care. A major gap preventing such efforts is the shortage of culturally appropriate, valid screening tools for identifying emotional and behavioral disorders among adolescents. In particular, studies have not conducted simultaneous validation of screening tools in multiple languages, to support screening and detection efforts in linguistically diverse populations. We aim to culturally adapt screening tools for emotional and behavioral disorders for use among adolescents in Nigeria, in order to facilitate future validation studies. METHODS: We used a rigorous mixed-method process to culturally adapt the Depression Self Rating Scale, Child PTSD Symptom Scale, and Disruptive Behavior Disorders Rating Scale. We employed expert translations, focus group discussions (N = 24), and piloting with cognitive interviewing (N = 24) to achieve semantic, content, technical, and criterion equivalence of screening tool items. RESULTS: We identified and adapted items that were conceptually difficult for adolescents to understand, conceptually non-equivalent across languages, considered unacceptable to discuss, or stigmatizing. Findings regarding problematic items largely align with existing literature regarding cross-cultural adaptation. CONCLUSIONS: Culturally adapting screening tools represents a vital first step toward improving community case detection.

20.
Rev Sci Instrum ; 79(1): 013905, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18248048

RESUMEN

A molecular beam apparatus has been developed for deposition and scattering experiments of size-selected clusters. The new setup combines a bimetallic laser ablation cluster source with a collinear time-of-flight mass spectrometer. Mass selection is achieved with a pulsed electrostatic mirror. A significantly improved transmission in combination with a reduction of the kinetic energy distribution of the mass selected clusters has been obtained. Without further modification of the apparatus, surface-induced dissociation of mass selected tin clusters has been investigated, demonstrating the possibility to combine cluster beam deposition and scattering experiments.

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