Biomedical subjects

W F Odenwald

Publications and source records attributed to W F Odenwald.

26 records · Page 2Linked to original sources

PubMed1987

Expression of a homeo domain protein in noncontact-inhibited cultured cells and postmitotic neurons.

The murine Hox 1.3 gene is one of six homeo box genes clustered on chromosome 6. Our analysis of Hox 1.3 cDNA and genomic clones indicates that the gene is organized into two exons and encodes a 270-amino-acid homeo domain protein. The predicted protein is rich in serine, glycine, and proline residues, and its homeo domain is identical to the Hox 2.1 domain. During embryogenesis, the gene is maximally expressed at midgestation but is also expressed to a lesser extent in many adult tissues possessing different cell lineages. Hox 1.3 transcripts are also present in cultured fibroblasts. The Hox 1.3 protein accumulates in the nuclei of nonconfluent cultured fibroblasts but is greatly diminished in contact-inhibited nongrowing cells. Thus, the expression of the Hox 1.3 gene correlates with growth in embryos and cultured cells. Paradoxically, it is also expressed in certain subsets of postmitotic, fully differentiated neurons, most notably the Purkinje neurons of the cerebellum, the pyramidal and dentate neurons of the hippocampus, and the motor neurons of the spinal cord. This complex pattern of expression suggests that Hox 1.3 may provide a function required by many cell types in addition to any role it may have in morphogenesis.

Amino Acid Sequence↗

PubMed1986

Stereo images of vesicular stomatitis virus assembly.

Viral assembly was studied by viewing platinum replicas of cytoplasmic and outer plasma membrane surfaces of baby hamster kidney cells infected with vesicular stomatitis virus. Replicas of the cytoplasmic surface of the basilar plasma membrane revealed nucleocapsids forming bullet-shaped tight helical coils. The apex of each viral nose cone was anchored to the membrane and was free of uncoiled nucleocapsid, whereas tortuous nucleocapsid was attached to the base of tightly coiled structures. Using immunoelectron microscopy, we identified the nucleocapsid (N) viral protein as a component of both the tight-coil and tortuous nucleocapsids, whereas the matrix (M) protein was found only on tortuous nucleocapsids. The M protein was not found on the membrane. Using immunoreagents specific for the viral glycoprotein (G protein), we found that the amount of G protein per virion varied. The G protein was consistently localized at the apex of viral buds, whereas the density of G protein on the shaft was equivalent to that in the surrounding membrane. These observations suggest that G-protein interaction with the nucleocapsid via its cytoplasmic domain may be necessary for the initiation of viral assembly. Once contact is established, nucleocapsid coiling proceeds with nose cone formation followed by formation of the helical cylinder. M protein may function to induce a nucleocapsid conformation favorable for coiling or may cross-link adjacent turns in the tight coil or both.

Animals↗

PubMed1983

Identification of a second synexin-like adrenal medullary and liver protein that enhances calcium-induced membrane aggregation.

Synexin, an approximately 47,000 Mr soluble protein isolated from adrenal medulla or liver, shows Ca2+-specific enhancement of the aggregation of chromaffin granule or other negatively charged biological or artificial membranes. We report the identification of second synexin-like protein (Mr approximately 56,000) from the same sources with similar Ca2+-specific membrane aggregation activities. However, the molecular weight, aggregation kinetics, susceptibility to protease inactivation and peptide maps of the two synexins are quite different, suggesting that they are entirely different proteins, and that the aggregation assay is only a convenient method for identifying a large number of Ca2+-specific proteins with diverse, yet to be defined activities.

Adrenal Medulla↗

PubMed1983

The chromaffin granule as a model for membrane fusion: implications for exocytosis.

Rapid freeze/freeze-fracture and thin section electron micrographic studies of the Ca2+-promoted aggregation and fusion of isolated bovine adrenal medullary chromaffin granule membranes show that the granules undergo a series of morphological changes. The contact region becomes quite extensive and the membrane curvature changes radically at the edge of the contact site. The core material retracts away from the contact site leaving an electron lucent "stripe"; however, it remains adjacent to the membrane in the non-contact areas. The pentalaminar double membrane of the contact region often shows breaks. Close examination reveals that the two granule membranes have fused and become one continuous membrane. Rearrangement of large membrane associated particles (MAPs) can be seen by freeze fracture after Ca2+-promoted granule-granule contact. The broken pentalaminar septum becomes smaller and may break down into globular structures. These observations suggest a series of reactions in which the granules first form an encounter complex, then a stable complex. The membranes within the contact region undergo lateral displacement of the proteins and phase separations of the lipids, and then fuse. Analysis of the kinetics of turbidity and fluorescence changes during granule aggregation and fusion support the main postulates of the model. The initial events of aggregation are facilitated by putative recognition proteins and K+ will promote all activities except fusion. Recent observations that several soluble proteins (synexin, and albumin) will act as fusogens are discussed in terms of the relevance to exocytosis in vivo.

Animals↗

PubMed1981

Lysosomal abnormalities in cultured schwann cells from a patient with peripheral neuropathy and continuous muscle fiber activity.

Schwann cell cultures were established from a sural nerve containing large membrane-bound vacuoles in its Schwann cells, obtained from a patient with neuropathy and continuous muscle fiber activity. Cultured Schwann cells contained many large membrane-bound vacuoles, presumably lysosomes, resembling those present in the biopsied nerve. The acid phosphatase reaction was excessive in the patient's cultured Schwann cells but practically negative in normal cultured Schwann cells. This study indicates that the patient's neuropathy is primary dysschwannian with abnormal lysosomes as a major abnormality.

Acid Phosphatase↗

PubMed1981

Ultrastructural and cytochemical characteristics of cultured rat Schwann cells.

Schwann cell cultures were established from sciatic nerve of 3 day-old rats. Described are the ultrastructural, histochemical and ultracytochemical properties of amyelic cultured rat Schwann cells. Ultrastructural characteristics of the cultured Schwann cells are compared to the Schwann cells of 3 day-old and adult rat sciatic nerve. These findings serve as a basis for comparison when studying experimentally induced alterations in the cultured Schwann cells as well as changes due to myelination in vitro.

Animals↗

PubMed1978

Immune electron microscopy of avian infectious bronchitis virus serotypes.

An immune electron microscopy agglutination technique in which emphasis is placed upon the importance of antigen-antibody equivalence has been developed as a possible method for the serotyping of avian infectious bronchitis viruses. The Connecticut and Massachusetts 41 serotypes were used as a model system. Stock virus concentrations were standardized by physical particle counts of virions sedimented directly onto electron microscope specimen grids. Suspensions containing approximately 150 virions per grid square were allowed to react with dilutions of homologous and heterologous antisera. Virions in these constant virus-variable serum mixtures were sedimented directly onto electron microscope specimen grids, and the relative degree of aggregation per grid was determined from the mean percent aggregation of five randomly selected grid squares. In homologous assays, regions of relative antibody excess, of equivalence, and of relative antigen excess were clearly evident. At equivalence, the mean percent aggregation was significantly higher than in the regions of relative antibody or antigen excess. In the heterologous systems, the degree of aggregation differed little from that of the virus controls containing no antiserum.

Agglutination Tests↗

PubMedDate not supplied

An indirect enzyme-linked immunosorbent assay (ELISA) for measuring antibodies in chickens infected with infectious bursal disease virus.

An immuno-enzyme assay for measuring infectious bursal disease antibodies in chickens is described. The test is performed rapidly after coating plates overnight with partially purified antigen prepared in cell culture. Coated plates can be stored for at last 4 months. The chromatographically purified rabbit anti-chicken immunoglobulin-G, conjugated to horseradish peroxidase, was used optimally at a dilution of 1:3,000. It could be stored for at least 10 months without a reduction in titer. The test is safe, highly reproducible, specific, and sensitive. Results can be read visually or by spectrophotometry. Antibodies could be detected as early as 4 days postinfection. Serum titers rose rapidly to high levels, ranging from 1:1,600 to 1:25,600 by one week postinfection. High titers persisted for up to one year. The results of this assay compare favorably with results obtained with the agar-gel precipitin and virus-neutralization tests.

Animals↗