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F G Klier

Publications and source records attributed to F G Klier.

31 records · Page 2Linked to original sources
PubMed1985

Clustered distribution of human placental alkaline phosphatase on the surface of both placental and cancer cells. Electron microscopic observations using gold-labeled antibodies.

The cell-surface distribution of human placental alkaline phosphatase (PLAP) on cultured cancer cells, A431 and HeLa TCRC-1, and on normal syncytial cells of placental tissue was examined in immunoelectron transmission microscopy using the gold-labeling technique. Chemically fixed cells were reacted with affinity-purified rabbit polyclonal antibodies to PLAP, and the antibodies were visualized using gold particles tagged with goat antirabbit IgG. On all cells PLAP was observed in clusters distributed throughout the membrane surface, including microvilli, but it was not expressed in desmosomes or along other dense regions on the membrane. Previous histochemical and immunochemical techniques failed to demonstrate clusters. The results show that (1) the gold-labeling technique allows a more precise localization of PLAP on the cell surface than previously employed methods, and (2) the distribution of the enzyme is the same on cultured cancer cells and on normal placental syncytial cells. The clustered distribution of PLAP is thus a general phenomenon and is probably influenced by the physiological function of the enzyme, which has yet to be defined.

Alkaline Phosphatase↗
PubMed1984

Molecular dimensions of the SS and FF phenotypes of human placental alkaline phosphatase. Rotary shadowing and negative staining electron microscope measurements.

The two most common homologous phenotypes (SS and FF) of human placental alkaline phosphatase were purified and observed in the electron microscope by rotary shadowing and negative staining techniques. In the rotary shadowing technique, the molecules of the two phenotypes appeared to be approximately elliptical with slit-like structures in the center of the molecules, suggestive of the groove between two subunits. The dimensions of the rotary-shadowed molecules were calculated as 10.1 nm X 5.7 nm for SS and 10.1 nm X 5.6 nm for FF phenotypes. The negative staining technique delivered more fine detail of the molecules than rotary shadowing. The predominant shape of the molecules in this method appeared to be rectangular, with a longitudinal stain-filled groove and with each of the half molecules (presumably 65,000 Mr subunit) very often appearing bi-lobed. This accounts for the molecules which appear to have four pronounced electron-transparent regions. The dimensions of the negatively stained rectangular-shaped molecules were measured as 7.5 nm X 5.5 nm for SS and 7.6 nm X 5.4 nm for FF phenotypes. No significant difference in electron microscopic appearance between the SS and FF phenotypes were observed.

Alkaline Phosphatase↗
PubMed1984

Acetylcholine receptor aggregation parallels the deposition of a basal lamina proteoglycan during development of the neuromuscular junction.

To determine the time course of synaptic differentiation, we made successive observations on identified, nerve-contacted muscle cells developing in culture. The cultures had either been stained with fluorescent alpha-bungarotoxin, or were maintained in the presence of a fluorescent monoclonal antibody. These probes are directed at acetylcholine receptors (AChR) and a basal lamina proteoglycan, substances that show nearly congruent surface organizations at the adult neuromuscular junction. In other experiments individual muscle cells developing in culture were selected at different stages of AChR accumulation and examined in the electron microscope after serial sectioning along the entire path of nerve-muscle contact. The results indicate that the nerve-induced formation of AChR aggregates and adjacent plaques of proteoglycan is closely coupled throughout early stages of synapse formation. Developing junctional accumulations of AChR and proteoglycan appeared and grew progressively, throughout a perineural zone that extended along the muscle surface for several micrometers on either side of the nerve process. Unlike junctional AChR accumulations, which disappeared within a day of denervation, both junctional and extrajunctional proteoglycan deposits were stable in size and morphology. Junctional proteoglycan deposits appeared to correspond to discrete ultrastructural plaques of basal lamina, which were initially separated by broad expanses of lamina-free muscle surface. The extent of this basal lamina, and a corresponding thickening of the postsynaptic membrane, also increased during the accumulation of AChR and proteoglycan along the path of nerve contact. Presynaptic differentiation of synaptic vesicle clusters became detectable at the developing neuromuscular junction only after the formation of postsynaptic plaques containing both AChR and proteoglycan. It is concluded that motor nerves induce a gradual formation and growth of AChR aggregates and stable basal lamina proteoglycan deposits on the muscle surface during development of the neuromuscular junction.

Animals↗
PubMed1983

Intermediate filament protein synthesis in preimplantation murine embryos.

The synthesis of two extraembryonic endodermal cytoskeletal proteins (Endo B, Mr = 50,000; Endo A, Mr = 55,000) was detected by immunoprecipitation at the 4- to 8-cell stage of preimplantation mouse development. The first detectable synthesis of both proteins occurs at about the same time as the earliest allocation of cells to the trophectodermal lineage. Both Endo A and B were identified in the two-dimensional gel pattern of blastocyst cytoskeletal proteins prepared by nonionic detergent and high-salt extraction. Endo A and B were identified as the y and x blastocyst cytoskeletal proteins, respectively, previously described by other investigators. Antibodies to Endo B are shown to react with intermediate filaments at the electron microscopic level, confirming that Endo B is an authentic intermediate filament protein. Previously, the TROMA 1 monoclonal antibody prepared by other investigators was shown to react specifically with Endo A and to decorate trophoblast cytoskeletons but did not react with the inner cell mass of blastocysts. Endo B antibodies are now also shown to decorate trophoblast cytoskeletons.

Animals↗
PubMed1983

A role for adherons in neural retina cell adhesion.

Embryonic chick neural retina cells release glycoprotein complexes, termed adherons, into their culture medium. When absorbed onto the surface of petri dishes, neural retina adherons increase the initial rate of neural retina cell adhesion; they also stimulate the rate of cell-cell aggregation. Adheron-stimulated adhesion is tissue specific, and the spontaneous aggregation of neural retina cells is inhibited by monovalent Fab' fragments prepared from an antiserum against neural retina adherons. Therefore cell surface antigenic determinants shared with adherons are involved in normal cell-cell adhesions. The particles from the heterogeneous neural retina population contain many proteins and several glycosaminoglycans. The adherons migrate as a symmetrical 12S peak on sucrose gradients and are predominantly 15-nm spheres when examined by electron microscopy. Finally, the specific activity of neural retina adherons increases from embryonic days 7 through 12 and then declines. These results suggest that glycoprotein particles may be involved in some of the adhesive interactions between neural retina cells and between the cells and their environment.

Animals↗
PubMed1981

Factors affecting the susceptibility of different strains of mice to experimental myasthenia gravis.

Mice immunized with purified AChR (T. californica) invariably form anti-AChR antibodies and often develop a condition of extreme muscular weakness and flaccid paralysis. Pharmacological, physiological, and ultrastructural studies indicate that the pathophysiology of EMG in the mouse closely resembles that of human MG. The single episode of muscular weakness typically found in mouse EMG differs from the acute phase of rat EMG in that macrophages and other phagocytes do not appear to play an active role in the destruction of the neuromuscular junction. The frequency of paralysis in mice immunized with AChR is highly strain dependent and is not attributable to polymorphisms with respect to susceptibility to cholinergic blockade. The incidence of paralysis does not correlate with the magnitude of the humoral response to either T. californica or mouse AChR. Because both paralyzed and nonparalyzed mice form antibodies which are able to increase the rate of both junctional and extrajunctional AChR degradation, the mere presence of antibodies reactive with cell surface antigenic determinants of AChR is not sufficient for the induction of paralysis. While it is still possible that antibody-induced degradation of AChR may be necessary for the induction of paralysis, these studies rule out the possibility that antigenic modulation of AChR is sufficient to account for the induction of paralysis in mouse EMG. In the present studies alleles of the two loci were identified which significantly effect the probability with which mice immunized with AChR can be expected to become paralyzed, the MHC and the IgCH region. Because one genotype, H-2b, Ig-1b segregated with high susceptibility to EMG in four strains derived from three dissimilar backgrounds, these studies strongly suggest that susceptibility to the development of paralysis is a heritable trait determined by regions of the mouse genome which regulate immune responsiveness.

Animals↗
PubMed1980

The modulation of neurotransmitter synthesis by steroid hormones and insulin.

Glucocorticoids stimulate tyrosine hydroxylase activity and catecholamine synthesis, while markedly inhibiting acetylcholine synthesis and storage in the a clone of sympathetic nerve-like cells. Nerve growth factor enhances the effect of glucocorticoids on tyrosine hydroxylase. The steroid effect is specific for glucocorticoids, since 11-desoxycortisol, testosterone, and estradiol-17 beta do not reproduce the effects of hydrocortisone and dexamethasone. Concomitant with the shift in neurotransmitter synthesis, there is an increase in the mean diameter of intracellular dense core vesicles. In contrast to glucocorticoids, insulin increases the specific activity of choline acetyltransferase through the interaction with typical insulin receptors. Insulin does not, however, alter the morphology of the cells, nor does it block the morphological response of the cells to nerve growth factor.

Acetylcholine↗
PubMed1977

Storage and release of acetylcholine by a clonal cell line.

The nerve cell line PC12, in its morphologically undifferentiated state, synthesizes, stores, and secretes catecholamines and acetylcholine. At least 60% of the basal level of neurotransmitter release is due to a calcium-dependent mechanism, and the rate of secretion is enhanced by increasing external potassium. A minimum of 80% of the intracellular acetylcholine and catecholamines are stored in particulate structures. The storage site for acetylcholine is dense core vesicles that can be distinguished from those containing catecholamines on the basis of vesicle density on sucrose gradients, vesicle size, and reserpine sensitivity. These results are discussed in relation to what are thought to be the early stages of synapse formation in cell culture.

Acetylcholine↗
PubMed1976

Development of a clonal myogenic cell line with unusual biochemical properties.

The morphological, ultrastructural, biochemical and electrophysiological properties of B104-F, a clonal cell line derived from a nitrosoethylurea-induced neoplasm in a rat, were studied as a function of the growth phase of the culture. Cells in exponentially growing cultures are mononucleate and produce action potentials when stimulated electrically. Stationary phase cultures contain three types of cells: cells of the first type are mononucleate and have long processes containing microfilaments and many parallel microtubules; cells of the second type are mononucleate but contain no microtubules and few microfilaments; and cells of the third type have ultrastructural features typical of multinucleate, striated myotubes. Multinucleate cells generate action potentials with both sodium and calcium components and are depolarized by acetylcholine. The acetylcholine response is blocked by d-tubocurarine. The specific activity of creatine phosphokinase is nine times higher in stationary phase cultures than in exponentially growing ones while the myokinase specific activity is unchanged. The gamma-aminobutyric acid content of the cells is 3.5- to 26-fold higher in stationary phase than in exponentially growing cultures, depending on the degree of fusion of the culture. The properties of B104-F are discussed in relation to the properties of developing skeletal muscle and of central nervous system cell lines.

Acetylcholine↗