RESUMO
Liquid-ordered (Lo) and liquid-disordered (Ld) phase coexistence has been suggested to partition the plasma membrane of biological cells into lateral compartments, allowing for enrichment or depletion of functionally relevant molecules. This dynamic partitioning might be involved in fine-tuning cellular signaling fidelity through coupling to the plasma membrane protein and lipid composition. In earlier work, giant plasma membrane vesicles, obtained by chemically induced blebbing from cultured cells, were observed to reversibly phase segregate at temperatures significantly below 37 degrees C. In this contribution, we compare the temperature dependence of fluid phase segregation in HeLa and rat basophilic leukemia (RBL) cells. We find an essentially monotonic temperature dependence of the number of phase-separated vesicles in both cell types. We also observe a strikingly broad distribution of phase transition temperatures in both cell types. The binding of peripheral proteins, such as cholera toxin subunit B (CTB), as well as Annexin V, is observed to modulate phase transition temperatures, indicating that peripheral protein binding may be a regulator for lateral heterogeneity in vivo. The partitioning of numerous signal protein anchors and full length proteins is investigated. We find Lo phase partitioning for several proteins assumed in the literature to be membrane raft associated, but observe deviations from this expectation for other proteins, including caveolin-1.
Assuntos
Anexina A5/química , Caveolina 1/química , Membrana Celular/química , Toxina da Cólera/química , Lipídeos de Membrana/química , Transição de Fase , Animais , Anexina A5/metabolismo , Caveolina 1/metabolismo , Membrana Celular/metabolismo , Toxina da Cólera/metabolismo , Células HeLa , Temperatura Alta , Humanos , Lipídeos de Membrana/metabolismo , RatosRESUMO
Two types of inclusion bodies were consistently observed under light microscopy in bean (Phaseolus vulgaris) leaf tissue infected with Bean rugose mosaic virus (BRMV), a species of the genus Comovirus, family Comoviridae. One type consisted of vacuolated inclusions found mainly in the cytoplasm of epidermal cells. The other type consisted of abundant crystalloid inclusions of different sizes and shapes found consistently in glandular hairs, guard cells, phloem tissue, xylem elements and occasionally in epidermal and mesophyll tissues. The two types of inclusion bodies stained with Azure A and Luxol Brilliant Green Bl-Calcomine Orange 2RS (O-G), and were similar to those seen to be caused by other species of comoviruses.
Assuntos
Comovirus/ultraestrutura , Fabaceae/virologia , Corpos de Inclusão Viral , Doenças das Plantas/virologia , Folhas de Planta/virologia , Plantas MedicinaisRESUMO
El angioma serpiginoso es una rara afeccion,nevoide,cronica,caracterizada por una ectasia vascular progresiva,localizada en dermis papilar y subpapilar. Desde el punto de vista clinico se observan lesiones maculosa,rojas,puntiformes,que adoptan disposicion serpiginosa. Se presenta el caso de un ninio de 10 anios,localizado en miembros inferiores, con el cual se adopto conducta expectante. Se describen la clinica y la histopatologia de la entidad y se establecen diagnosticos diferenciales con dermatosis purpuricas y pigmentarias,angioqueratoma corporal difuso,angioqueratoma circunscripto,telangiectasia nevoide y nevo flameo