RESUMEN
As part of an on-going project to characterize compounds from immature conifer cones with antibacterial or modulatory activity against multidrug-resistant (MDR) strains of Staphylococcus aureus, eight compounds were isolated from the cones of Chamaecyparis lawsoniana. The active compounds were mainly diterpenes, with minimum inhibitory concentrations ranging from 4 to 128 microg/ml against MDR effluxing S. aureus strains and two epidemic methicillin-resistant (EMRSA) clinical isolates. The compounds extracted were the diterpenes ferruginol, pisiferol and its epimer 5-epipisiferol, formosanoxide, trans-communic acid and torulosal, the sesquiterpene oplopanonyl acetate and the germacrane 4beta-hydroxygermacra-1(10)-5-diene. Some of these compounds also exhibited modulatory activity in potentiating antibiotic activity against effluxing strains and ferruginol, used at a sub-inhibitory concentration, resulted in an 80-fold potentiation of oxacillin activity against strain EMRSA-15. An efflux inhibition assay using an S. aureus strain possessing the MDR NorA efflux pump resulted in 40% inhibition of ethidium bromide efflux at 10 microM ferruginol (2.86 microg/ml). We report the (1)H and (13)C NMR data for the cis A/B ring junction epimer of pisiferol which we have named 5-epipisiferol. We also unambiguously assign all (1)H and (13)C NMR resonances for trans-communic acid.
Asunto(s)
Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Chamaecyparis/anatomía & histología , Chamaecyparis/química , Farmacorresistencia Bacteriana , Antibacterianos/química , Proteínas Bacterianas/metabolismo , Pruebas de Sensibilidad Microbiana , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Resonancia Magnética Nuclear Biomolecular , Staphylococcus aureus/efectos de los fármacosRESUMEN
Enteropathy-associated T cell lymphoma (EATL) is a lethal, and the most common, neoplastic complication of celiac disease. Here, we defined the genetic landscape of EATL through whole-exome sequencing of 69 EATL tumors. SETD2 was the most frequently silenced gene in EATL (32% of cases). The JAK-STAT pathway was the most frequently mutated pathway, with frequent mutations in STAT5B as well as JAK1, JAK3, STAT3, and SOCS1 We also identified mutations in KRAS, TP53, and TERT Type I EATL and type II EATL (monomorphic epitheliotropic intestinal T cell lymphoma) had highly overlapping genetic alterations indicating shared mechanisms underlying their pathogenesis. We modeled the effects of SETD2 loss in vivo by developing a T cell-specific knockout mouse. These mice manifested an expansion of γδ T cells, indicating novel roles for SETD2 in T cell development and lymphomagenesis. Our data render the most comprehensive genetic portrait yet of this uncommon but lethal disease and may inform future classification schemes.
Asunto(s)
Linfoma de Células T Asociado a Enteropatía/fisiopatología , N-Metiltransferasa de Histona-Lisina/fisiología , Animales , Variaciones en el Número de Copia de ADN/genética , Linfoma de Células T Asociado a Enteropatía/clasificación , Linfoma de Células T Asociado a Enteropatía/genética , Femenino , Perfilación de la Expresión Génica , Silenciador del Gen , Humanos , Masculino , Ratones Noqueados , Persona de Mediana Edad , Mutación/genética , Análisis de Secuencia de ADN , Linfocitos T/fisiologíaRESUMEN
The phenolic diterpene totarol had good antimicrobial activity against effluxing strains of Staphylococcus aureus. Subinhibitory concentrations reduced the MICs of selected antibiotics, suggesting that it may also be an efflux pump inhibitor (EPI). A totarol-resistant mutant that overexpressed norA was created to separate antimicrobial from efflux inhibitory activity. Totarol reduced ethidium efflux from this strain by 50% at 15 microM (1/4x MIC), and combination studies revealed marked reductions in ethidium MICs. These data suggest that totarol is a NorA EPI as well as an antistaphylococcal antimicrobial agent.
Asunto(s)
Proteínas Bacterianas/metabolismo , Diterpenos/farmacología , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Staphylococcus aureus/efectos de los fármacos , Abietanos , Antibacterianos/química , Antibacterianos/farmacología , Diterpenos/química , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Staphylococcus aureus/metabolismoRESUMEN
Conventional methods of isolating and reconstituting ryanodine receptors (RyRs) from native membranes into proteoliposomes take a minimum of 2 days to complete. We have developed an alternative strategy that can be used to isolate and reconstitute functional RyRs in just 3 h with a similar degree of purification. RyRs isolated by this method display characteristic functional behaviour as assessed by radioligand binding and single channel analyses.