RESUMEN
Sex workers are among the most stigmatised people globally, with sex workers in Vietnam being no exception. Self-stigma affects sex workers adversely, harming psychological health and acting as a barrier to seeking health care. To inform programmes and interventions to improve well-being, identifying unhelpful or negative core beliefs may provide the basis from which individuals can be supported. With this in mind, this study aimed to gain the perspective of sex workers in Vietnam on the contexts of their working lives. Data were collected in Hanoi. Fourteen semi-structured interviews were conducted with Vietnamese sex workers over the age of 18 who were working or formerly worked in Vietnam. Data were analysed manually, informed by theoretical models of self-stigma using inductive thematic analysis. The analysis identified negative/unhelpful core beliefs (disclosure, self-stigma and shame, sexuality, sexual pleasure relationships, health care); contextual life circumstances (sex work, violence, traditional education); and coping mechanisms (problem-focused coping, emotion-focused coping). Findings identify the importance of core beliefs in understanding self-stigma, paving the way for programmes and interventions to address self-stigma among sex workers.
Asunto(s)
Adaptación Psicológica , Aceptación de la Atención de Salud , Trabajadores Sexuales/psicología , Estigma Social , Adulto , Femenino , Humanos , Entrevistas como Asunto , Masculino , Vergüenza , VietnamRESUMEN
Metabolic homeostasis and circadian rhythms are closely intertwined biological processes. Nuclear receptors, as sensors of hormonal and nutrient status, are actively implicated in maintaining this physiological relationship. Although the orphan nuclear receptor estrogen-related receptor α (ERRα, NR3B1) plays a central role in the control of energy metabolism and its expression is known to be cyclic in the liver, its role in temporal control of metabolic networks is unknown. Here we report that ERRα directly regulates all major components of the molecular clock. ERRα-null mice also display deregulated locomotor activity rhythms and circadian period lengths under free-running conditions, as well as altered circulating diurnal bile acid and lipid profiles. In addition, the ERRα-null mice exhibit time-dependent hypoglycemia and hypoinsulinemia, suggesting a role for ERRα in modulating insulin sensitivity and glucose handling during the 24-hour light/dark cycle. We also provide evidence that the newly identified ERRα corepressor PROX1 is implicated in rhythmic control of metabolic outputs. To help uncover the molecular basis of these phenotypes, we performed genome-wide location analyses of binding events by ERRα, PROX1, and BMAL1, an integral component of the molecular clock. These studies revealed the existence of transcriptional regulatory loops among ERRα, PROX1, and BMAL1, as well as extensive overlaps in their target genes, implicating these three factors in the control of clock and metabolic gene networks in the liver. Genomic convergence of ERRα, PROX1, and BMAL1 transcriptional activity thus identified a novel node in the molecular circuitry controlling the daily timing of metabolic processes.
Asunto(s)
Proteínas de Homeodominio/metabolismo , Hígado/metabolismo , Receptores de Estrógenos/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Factores de Transcripción ARNTL/genética , Factores de Transcripción ARNTL/metabolismo , Animales , Ácidos y Sales Biliares/sangre , Glucemia/análisis , Western Blotting , Proteínas CLOCK/metabolismo , Células COS , Chlorocebus aethiops , Colesterol/sangre , Ritmo Circadiano , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Gluconeogénesis , Glucólisis , Células Hep G2 , Proteínas de Homeodominio/genética , Homeostasis , Humanos , Insulina/sangre , Hígado/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Actividad Motora , Fotoperiodo , Regiones Promotoras Genéticas , Unión Proteica , Interferencia de ARN , Receptores de Estrógenos/genética , Triglicéridos/sangre , Proteínas Supresoras de Tumor/genética , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Ampullosporin A (AmpA), a 15mer peptalbol containing seven Aib residues is able to induce pigmentation on Phoma destructiva and hypothermia in mice, as well as to exhibit a neuroleptic effect. A circular dichroism study of ampullosporin A and its analogues was carried out in organic solvents with different polarities and detergent micelles to determine the relationship between their conformational flexibility and biological activities. The analogues were obtained by modifying the N- and C-termini of ampullosporin A. Furthermore, Gln and Leu were systematically substituted by Ala and Aib residues were replaced by Ala and/or Ac6c. To estimate the helicity of the analogues, the CD spectrum of AmpA recorded in acetonitrile was correlated to its crystal structure. All analogues displayed similar CD curve shapes in organic solvents with the ratio between two negative band intensities R = [theta]n-pi*/[theta]pi-pi* < 1. In acetonitrile, most of the analogues adopted a 70%-85% helical structure, which was higher than the average of 40%-60% obtained in TFE. In detergent micelles, the analogues were distinguishable by their CD profiles. For most of the biologically active analogues, the CD spectra in detergent micelles were characterized by a R ratio > 1 and increased helicity compared with those recorded in TFE, suggesting that the interaction of the peptides with the membrane and peptide association was necessary for their hypothermic effect.
Asunto(s)
Dicroismo Circular , Proteínas Fúngicas/química , Péptidos/química , Secuencia de Aminoácidos , Permeabilidad de la Membrana Celular , Detergentes/farmacología , Proteínas Fúngicas/síntesis química , Modelos Biológicos , Peptaiboles , Péptidos/síntesis química , Estructura Secundaria de Proteína/efectos de los fármacos , Solventes/farmacología , Relación Estructura-Actividad , TemperaturaRESUMEN
Ampullosporin A is a 15-mer peptaibol type polypeptide that induces pigment formation by the fungus Phoma destructiva, forms voltage-dependent ion channels in membranes and exhibits hypothermic effects in mice. The structure of ampullosporin A has been determined by x-ray crystallography. This is the first three-dimensional (3D) structure of the peptaibol subfamily SF6. From the N-terminus to residue 13 the molecule adopts an approximate right-handed alpha-helical geometry, whereas a less regular structure pattern with beta-turn characteristics is found in the C-terminus. Even though ampullosporin A does not contain a single proline or hydroxyproline it is significantly bent. It belongs to both the shortest and the most strongly bent peptaibol 3D structures. The straight structure part encompasses residues Ac-Trp(1)-Aib(10) and is thus less extended than the alpha-helical subunit. The 3D structure of ampullosporin A is discussed in relation to other experimentally determined peptaibol structures and in the context of its channel-forming properties. As a part of this comparison a novel bending analysis based on a 3D curvilinear axis describing the global structural characteristics has been proposed and applied to all 3D peptaibol structures. A sampling of 2500 conformations using different molecular dynamics protocols yields, for the complete ampullosporin A structure, an alpha-helix as the preferred conformation in vacuo with almost no bend. This indicates that solvent or crystal effects may be important for the experimentally observed peptide backbone bending characteristics of ampullosporin A.
Asunto(s)
Proteínas Fúngicas/química , Ionóforos/química , Péptidos/química , Antibacterianos/química , Cristalización , Cristalografía por Rayos X , Dimerización , Canales Iónicos/química , Peptaiboles , Conformación Proteica , Solventes/farmacologíaRESUMEN
A series of analogues of the fungal peptaibol type metabolite ampullosporin A containing modifications in the C and N terminus as well as alpha-aminoisobutyric acid (Aib) substitutions in different positions of the peptide were synthesized by solid phase synthesis using the 9-fluorenylmethyloxycarbonyl strategy. Depending on the sequence position, couplings were performed with 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate/1-hydroxybenzotriazole and tetramethylfluoroformamidinium hexafluorophosphate, respectively. The structures of the target peptides were analyzed by electrospray ionization mass spectrometry and chromatographic methods (high-performance liquid chromatography, thin-layer chromatography). The biological activities of these compounds have been evaluated by assaying their potencies for the induction of pigment formation on the fungus Phoma destructiva as well as for the induction of hypothermia and inhibition of locomotoric activity in mice and were compared to the naturally occurring ampullosporins. Native ampullosporin A and analogues with C-terminal Leu or Leu-NH(2) showed comparable activity in the pigmentation assay. Similarly, the ampullosporin A analogues with N-terminal aromatic amino acid residues, such as D-Trp and Tic, also have high potency for pigment formation. The peptides containing structural modifications of ampullosporin A by systematic replacement of Aib by Ala (Ala scan) displayed moderate or high activity in the pigmentation assay, whereas simultaneous substitution of all Aib residues by Ala and Ile, respectively, or by insertion of nonaromatic residues into position 1 resulted in a loss of the effect on P. destructiva. Most of the compounds with no or weak activity in the microbial assay were not active in the hypothermic test, too, except the compound with 1-amino-1-cyclohexane carboxylic acid in position 4 instead of Aib. However, only a few compounds with high potency for pigmentation induction were found to produce strong hypothermia in mice. Thus, in contrast to the native ampullosporins, we succeeded to a certain degree in differentiation of the bioactivities with our synthetic analogues.