RESUMEN
Phytochemical investigation of the endophytic fungus Coniothyrium sp. resulted in the isolation of a new phenoxyphenyl ether, named coniothyren (1), and two known compounds, coniol (2) and (+)-epoxydon (3). The structure of the new compound was elucidated by detailed spectroscopic analysis, namely, (1)H NMR, (13)C NMR, COSY, HMQC, HMBC, and HR-EI-MS. Preliminary studies demonstrated that (+)-epoxydon (3) displayed good antibacterial and antialgal activities toward Bacillus megaterium and Chlorella fusca, respectively.
Asunto(s)
Antibacterianos/aislamiento & purificación , Ascomicetos/química , Éteres/aislamiento & purificación , Éteres Fenílicos/aislamiento & purificación , Antibacterianos/química , Antibacterianos/farmacología , Éteres/química , Éteres/farmacología , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Éteres Fenílicos/química , Éteres Fenílicos/farmacologíaRESUMEN
Pulmonary arterial endothelial function is known to be affected in patients with idiopathic pulmonary arterial hypertension (IPAH). Current reports also detected peripheral systemic arterial dysfunction in IPAH patients. The purpose of this study was to assess whether there is a relation between pulmonary arterial and systemic arterial endothelial function. Pulmonary arterial endothelium-dependent relaxation was assessed by changes in pulmonary blood flow in response to acetylcholine which were determined using intravascular Doppler flow measurements. Pulmonary flow reserve (PFR) was calculated as the ratio of pulmonary blood flow velocity in response to acetylcholine relative to baseline values. Systemic arterial endothelial function was assessed by the vascular response to reactive hyperemia, and was recorded non-invasively by peripheral arterial finger tonometry under standardized conditions. Thirteen children and young adults [mean age 16.7 (±5.6) years] with IPAH and 13 age-/gender-matched controls were included in the study. Digital reactive hyperemic index (RHI) of the IPAH patients was 1.54 (±0.69), and of the controls was 1.67 (±0.66) [p = 0.64]. The mean baseline flow velocity in the segmental pulmonary artery of all patients was 18.5 (±5.5) cm/s, increasing to 27.4 (±12.3) cm/s (p = 0.003) during acetylcholine infusion. The calculated mean PFR was 1.48 (±0.4). There was no significant correlation between the PFR and RHI (r = 0.19; p = 0.54). According to our results, systemic arterial endothelial function assessed by peripheral arterial finger tonometry was not significantly impaired in children and young adults with IPAH compared with age-/gender-matched controls. There was no correlation between systemic arterial and pulmonary arterial endothelial function, suggesting that different mechanisms may contribute to their pathogenesis and progression.
Asunto(s)
Endotelio Vascular/fisiopatología , Hipertensión Pulmonar Primaria Familiar/fisiopatología , Arteria Pulmonar/fisiopatología , Acetilcolina , Adolescente , Velocidad del Flujo Sanguíneo , Niño , Femenino , Hemodinámica , Humanos , Hiperemia , Masculino , Vasodilatadores , Adulto JovenRESUMEN
OBJECTIVES: The purpose of our study was to assess pulmonary endothelial function by vasodilator response to acetylcholine (Ach) administered in segmental pulmonary arteries in children with idiopathic pulmonary arterial hypertension (IPAH). We hypothesized that there was a relationship among pulmonary endothelial response to Ach, severity of the disease, and clinical outcome. BACKGROUND: IPAH may be associated with pulmonary endothelial dysfunction; however, data regarding the impact of endothelial dysfunction on severity and prognosis of this disease are limited. METHODS: Forty-three children and adolescents (mean age: 10.4 ± 5.5 years) with IPAH were included in the study. Changes in pulmonary blood flow in response to Ach were determined using intravascular Doppler flow measurements. Pulmonary flow reserve (PFR) was calculated as the ratio of pulmonary blood flow velocity in response to Ach relative to baseline values. RESULTS: Mean PFR of all patients was 1.58 ± 0.67. Mean follow-up after catheterization was 55.7 ± 41.9 months. Freedom from serious cardiovascular events (lung transplantation or death) was 83% after 2 years, 76% after 3 years, and 57% after 5 years. PFR was related significantly to World Health Organization functional class. Receiver-operating characteristic curves revealed a PFR of 1.4 as the best cutoff value. Kaplan-Meier analysis demonstrated that a PFR of <1.4 was highly predictive for cardiovascular events (log-rank [Mantel Cox] chi-square: 12.49, p < 0.0001). CONCLUSIONS: Our study demonstrates a strong relationship between pulmonary endothelial response to Ach and prognosis of children with IPAH. As an adjunct to the usual testing protocol, this method provides additional information for therapeutic guidance.
Asunto(s)
Endotelio Vascular/fisiopatología , Hipertensión Pulmonar/fisiopatología , Pulmón/fisiopatología , Acetilcolina/farmacología , Adolescente , Bloqueadores de los Canales de Calcio/uso terapéutico , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/fisiopatología , Niño , Preescolar , Hipertensión Pulmonar Primaria Familiar , Femenino , Humanos , Hipertensión Pulmonar/complicaciones , Hipertensión Pulmonar/tratamiento farmacológico , Flujometría por Láser-Doppler , Masculino , Pronóstico , Arteria Pulmonar/fisiopatología , Flujo Sanguíneo Regional/efectos de los fármacos , Vasodilatadores/farmacologíaRESUMEN
BACKGROUND: Membrane proteins (MPs) play key roles in signal transduction. However, understanding their function at a molecular level is mostly hampered by the lack of protein in suitable amount and quality. Despite impressive developments in the expression of prokaryotic MPs, eukaryotic MP production has lagged behind and there is a need for new expression strategies. In a pilot study, we produced a Drosophila glutamate receptor specifically in the eyes of transgenic flies, exploiting the naturally abundant membrane stacks in the photoreceptor cells (PRCs). Now we address the question whether the PRCs also process different classes of medically relevant target MPs which were so far notoriously difficult to handle with conventional expression strategies. PRINCIPAL FINDINGS: We describe the homologous and heterologous expression of 10 different targets from the three major MP classes--G protein-coupled receptors (GPCRs), transporters and channels in Drosophila eyes. PRCs offered an extraordinary capacity to produce, fold and accommodate massive amounts of MPs. The expression of some MPs reached similar levels as the endogenous rhodopsin, indicating that the PRC membranes were almost unsaturable. Expression of endogenous rhodopsin was not affected by the target MPs and both could coexist in the membrane stacks. Heterologous expression levels reached about 270 to 500 pmol/mg total MP, resulting in 0.2-0.4 mg purified target MP from 1 g of fly heads. The metabotropic glutamate receptor and human serotonin transporter--both involved in synaptic transmission--showed native pharmacological characteristics and could be purified to homogeneity as a prerequisite for further studies. SIGNIFICANCE: We demonstrate expression in Drosophila PRCs as an efficient and inexpensive tool for the large scale production of functional eukaryotic MPs. The fly eye system offers a number of advantages over conventional expression systems and paves the way for in-depth analyses of eukaryotic MPs that have so far not been accessible to biochemical and biophysical studies.
Asunto(s)
Drosophila melanogaster/metabolismo , Células Eucariotas/metabolismo , Canales Iónicos/biosíntesis , Proteínas de Transporte de Membrana/biosíntesis , Células Fotorreceptoras de Invertebrados/metabolismo , Receptores de Superficie Celular/biosíntesis , Animales , Membrana Celular/metabolismo , Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Canales Iónicos/aislamiento & purificación , Proteínas de Transporte de Membrana/aislamiento & purificación , Neurotransmisores/metabolismo , Receptores de Superficie Celular/aislamiento & purificación , Receptores de Glutamato/metabolismo , Proteínas Recombinantes/aislamiento & purificación , Rodopsina/metabolismoRESUMEN
BACKGROUND: The fundamental role of the light receptor rhodopsin in visual function and photoreceptor cell development has been widely studied. Proper trafficking of rhodopsin to the photoreceptor membrane is of great importance. In human, mutations in rhodopsin involving its intracellular mislocalization, are the most frequent cause of autosomal dominant Retinitis Pigmentosa, a degenerative retinal pathology characterized by progressive blindness. Drosophila is widely used as an animal model in visual and retinal degeneration research. So far, little is known about the requirements for proper rhodopsin targeting in Drosophila. METHODOLOGY/PRINCIPAL FINDINGS: Different truncated fly-rhodopsin Rh1 variants were expressed in the eyes of Drosophila and their localization was analyzed in vivo or by immunofluorescence. A mutant lacking the last 23 amino acids was found to properly localize in the rhabdomeres, the light-sensing organelle of the photoreceptor cells. This constitutes a major difference to trafficking in vertebrates, which involves a conserved QVxPA motif at the very C-terminus. Further truncations of Rh1 indicated that proper localization requires the last amino acid residues of a region called helix 8 following directly the last transmembrane domain. Interestingly, the very C-terminus of invertebrate visual rhodopsins is extremely variable but helix 8 shows conserved amino acid residues that are not conserved in vertebrate homologs. CONCLUSIONS/SIGNIFICANCE: Despite impressive similarities in the folding and photoactivation of vertebrate and invertebrate visual rhodopsins, a striking difference exists between mammalian and fly rhodopsins in their requirements for proper targeting. Most importantly, the distal part of helix 8 plays a central role in invertebrates. Since the last amino acid residues of helix 8 are dispensable for rhodopsin folding and function, we propose that this domain participates in the recognition of targeting factors involved in transport to the rhabdomeres.
Asunto(s)
Rodopsina/metabolismo , Secuencia de Aminoácidos , Animales , Animales Modificados Genéticamente , Drosophila , Técnica del Anticuerpo Fluorescente , Microscopía Confocal , Datos de Secuencia Molecular , Rodopsina/química , Homología de Secuencia de AminoácidoRESUMEN
Cultivation of the marine-derived streptomycete isolate B8005 delivered three known antibiotics, resistomycin (1), resistoflavin (3a) and tetracenomycin (4), and a further member of the rare resistomycin class, the weakly antibiotically active 1-hydroxy-1-norresistomycin (2). From a related marine strain B4842, 1 and resistoflavin methyl ether (3b) have been isolated. The formation of 2 is of interest from a biosynthetic point of view.