Caveolin interacts with the angiotensin II type 1 receptor during exocytic transport but not at the plasma membrane

The mechanisms involved in angiotensin II type 1 receptor (AT(1)-R) trafficking and membrane localization are largely unknown. In this study, we examined the role of caveolin in these processes. Electron microscopy of plasma membrane sheets shows that the AT(1)-R is not concentrated in caveolae but is clustered in cholesterol-independent microdomains; upon activation, it partially redistributes to lipid rafts. Despite the lack of AT(1)-R in caveolae, AT(1)-R. caveolin complexes are readily detectable in cells co-expressing both proteins. This interaction requires an intact caveolin scaffolding domain because mutant caveolins that lack a functional caveolin scaffolding domain do not interact with AT(1)-R. Expression of an N-terminally truncated caveolin-3, CavDGV, that localizes to lipid bodies, or a point mutant, Cav3-P104L, that accumulates in the Golgi mislocalizes AT(1)-R to lipid bodies and Golgi, respectively. Mislocalization results in aberrant maturation and surface expression of AT(1)-R, effects that are not reversed by supplementing cells with cholesterol. Similarly mutation of aromatic residues in the caveolin-binding site abrogates AT(1)-R cell surface expression. In cells lacking caveolin-1 or caveolin-3, AT(1)-R does not traffic to the cell surface unless caveolin is ectopically expressed. This observation is recapitulated in caveolin-1 null mice that have a 55% reduction in renal AT(1)-R levels compared with controls. Taken together our results indicate that a direct interaction with caveolin is required to traffic the AT(1)-R through the exocytic pathway, but this does not result in AT(1)-R sequestration in caveolae. Caveolin therefore acts as a molecular chaperone rather than a plasma membrane scaffold for AT(1)-R.

Tissue engineering for bone regeneration using differentiated alveolar bone cells in collagen scaffolds

Regeneration of osseous defects by a tissue-engineering approach provides a novel means of treatment utilizing cell biology, materials science, and molecular biology. In this study the concept of tissue engineering was tested with collagen type I matrices seeded with cells with osteogenic potential and implanted into sites where osseous damage had occurred. Explant cultures of cells from human alveolar bone and gingiva were established. When seeded into a three-dimensional type I collagen-based scaffold, the bone-derived cells maintained their osteoblastic phenotype as monitored by mRNA and protein levels of the bone-related proteins including bone sialoprotein, osteocalcin, osteopontin, bone morphogenetic proteins 2 and 4, and alkaline phosphatase. These in vitro-developed matrices were implanted into critical-size bone defects in skulls of immunodeficient (SCID) mice. Wound healing was monitored for up to 4 weeks. When measured by microdensitometry the bone density within defects filled with osteoblast-derived matrix was significantly higher compared with defects filled with either collagen scaffold alone or collagen scaffold impregnated with gingival fibroblasts. New bone formation was found at all the sites treated with the osteoblast-derived matrix at 28 days, whereas no obvious new bone formation was identified at the same time point in the control groups. In situ hybridization for the human-specific Alu gene sequence indicated that the newly formed bone tissue resulted from both transplanted human osteoblasts and endogenous mesenchymal stem cells. The results indicate that cells derived from human alveolar bone can be incorporated into bioengineered scaffolds and synthesize a matrix, which on implantation can induce new bone formation.

Diagnosis of rubella infection by detecting specific immunoglobulin M antibodies in saliva samples: a clinic-based study in Niterói, RJ, Brazil

This study was designed to investigate whether saliva could be a feasible alternative to serum for the diagnosis of recent rubella infection in a clinic setting. Forty-five paired blood and saliva samples collected 1 to 29 days after onset of illness were tested for specific immunoglobulin (Ig) M by antibody-capture radioimmunoassay (MACRIA). Rubella IgM was detected in all serum samples and in 38 (84.4%) saliva specimens. Forty-six serum and saliva samples from other patients with rash diseases were tested by MACRIA for control purposes and two saliva specimens were reactive. The saliva test had specificity of 96%. These results indicate that salivary IgM detection may be a convenient non-invasive alternative to serum for investigation of recent rubella cases, especially for disease surveillance and control programmes.

Densidades e cultivares de soja RR em dois anos de plantio para o Sul de Minas Gerais.

Objetivou-se identificar as melhores populações de plantas de soja de três principais cultivares recém-lançadas para fins de recomendação aos produtores do sul de Minas Gerais. Por dois anos avaliou-se as cultivares BRSMG 760SRR, BRSMG 780RR e BRSMG 820RR, submetidas às populações 100.000, 200.000, 300.000 e 400.000 plantas por hectare, utilizando-se blocos casualizados com três repetições. Determinou-se altura de plantas e de inserção de 1° legume, índice de acamamento, n° de legumes por planta, n° de grãos por legume, peso de 100 grãos e rendimento de grãos. A cultivar BRSMG 760SRR mostrou-se superior apresentando o máximo rendimento de grãos (4.973kg ha-1) com 269.000 plantas ha-1. As demais cultivares não sofreram influência da variação populacional, podendo ser cultivadas com 200.000 plantas ha.

Caracterização de cultivares de soja em diversas densidades de plantio para o Estado de Minas Gerais.

Objetivou-se identificar as melhores populações de plantas de soja de cultivares recém lançadas, para fins de recomendação aos produtores do sul de Minas Gerais. Selecionou-se 3 cultivares convencionais e 3 transgênicas RR, semeadas em 4 populações de plantas. As cultivares transgênicas se mostraram altamente produtivas, não tendo a população de plantas alterado o rendimento de grãos. Para ambos os ensaios as maiores alturas de inserção do 1° legume foram obtidas com as maiores populações de plantas.

Observations of air composition in Brazil between the Equator and 20°s during the dry season.

Field measurement programs in Brazil during the dry season months of August and September in 1979 and 1980 have demonstrated the great importance of the continental tropics in global air chemistry. Especially in the mixed layer, the air composition over land is much different from that over the ocean and the land areas are clearly longe scale sources of many inportant trace gases. During the dry season much biomass, burning takes place especially in the cerrado regions leading to substantial emission of air pollutants, such as CO, NOx, N2O, CH4 and other hydrocarbons. Ozone concentrations are alsoenhanced due to photochemical reactions. Biogenic organic emissions from tropical forests play likewise an important role in the photochemistry of the atmosphere. Carbon monoxide was found to be present in high concentrations in the boundary layer of the tropical forest, but ozone concentrations were much lower than in the cerrado.

The terrestrial air-breathing mollusks of the United States, and the adjacent territories of North America: described and illustrated by Amos Binney. Ed. by Augustus A. Gould ...

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The terrestrial air-breathing mollusks of the United States, and the adjacent territories of North America: described and illustrated by Amos Binney. Ed. by Augustus A. Gould ...

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The terrestrial air-breathing mollusks of the United States, and the adjacent territories of North America: described and illustrated by Amos Binney. Ed. by Augustus A. Gould ...

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The terrestrial air-breathing mollusks of the United States, and the adjacent territories of North America: described and illustrated by Amos Binney. Ed. by Augustus A. Gould ...

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The terrestrial air-breathing mollusks of the United States, and the adjacent territories of North America: described and illustrated by Amos Binney. Ed. by Augustus A. Gould ...

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Anomalia em Coscinodiscus oculus-iridis ehrenberg, 1839 (Diatomácea)

The author describes an anomalous specimen in diatom Coscinodiscus oculus-iridis Ehr., 1839, caught from Guanabara Bat, (22º 51' 8" Lat. S. - 43º 14' 3" Long. W. G.); its dorsal face (fig. 1), is different from the ventral one, (fig. 2).