Evolutionary conservation of an epitope associated with striated rootlets in different epithelial ciliated cells.

In ciliated cells of metazoa, striated rootlets associated with basal bodies anchor the ciliary apparatus to the cytoskeleton. We have used here a monoclonal antibody against a 175 kDa protein associated with the striated rootlets of quail ciliated cells, to study ciliated cells of different species. In mussel gill epithelium the antibody recognized a protein of 92 kDa which shows a periodic distribution along the striated rootlets.

Relocalization of an 82-kDa protein from lampbrush loops into the nucleoskeleton during amphibian oogenesis.

Affinity-purified antibodies directed against an 82-kDa oocyte nuclear protein ofPleurodeles waltl (Amphibia, Urodela) were prepared using antigen bound to nitrocellulose paper. The specificity of the antibody was controlled on two-dimensional electrophoretic gels of nuclear proteins. The intranuclear distribution of the 82-kDa protein was analyzed by the indirect immunofluorescence method on spreads of oocyte nuclear content.

Isolation of cDNAs from a mouse astroglial cell line by a subtracted cDNA library.

Astrocytes belong to the glial cell population and represent a major subclass of the CNS. Although different subtypes of astrocytes have been described according to their morphological characteristics, biochemical markers of each subtype of astrocytes are not yet available. We have thus undertaken to compare gene expression pattern of different astroglial subtypes.

Changes in phospholipid composition of tracheal aspirates from newborns with hyaline membrane disease or transient tachypnoea.

Phospholipid analysis of tracheal aspirates obtained from 37 newborn infants, all intubated for respiratory diseases, was performed in order to compare infants having hyaline membrane disease (HMD) (n = 11), to those presenting with transient tachypnoea (TT) (n = 16) or another respiratory disorder (n = 10) and to determine if distinguishing features could be discovered for HMD or TT. In the HMD group, a significantly lower amount (about 20%) of recoverable phospholipid material was observed. Furthermore, the groups differed in their phospholipid profile: infants with HMD presented with a deficiency in saturated phosphatidylcholine, but had a related increase in unsaturated phosphatidylcholine, and an increased proportion of phosphatidylethanolamine (about 2.

Effects of cold shock treatment on lampbrush chromosomes of amphibian oocytes.

When females of the newt Pleurodeles waltl, normally raised in our laboratory at 20 degrees C, were placed in 8 degrees C water for several days, striking modifications occurred in the structure of oocyte lampbrush chromosomes: numerous normal-type lateral loops were partially reduced in size and number, while hyperdeveloped loops of a new morphological type occurred at constant, reproducible loci. However, induction of these cold loops apparently was not accompanied by preferential RNA synthesis at their levels. Cold loops resulted from the decompaction of specific landmarks, the granular loops.

Localization of pigment cells in cultured frog skin.

The pigmentation pattern of ventral skin of the frog Rana esculenta consists mainly of melanophores and iridophores, rather than the three pigment cells (xanthophores, iridophores, and melanophores) which form typical dermal chromatophore units in dorsal skin. The present study deals with the precise localization and identification of the types of pigment cells in relation to their position in the dermal tracts of uncultured or cultured frog skins. Iridophores were observed by dark-field microscopy; both melanophores and iridophores were observed by transmission electron microscopy.

Immunocytochemical study of the formation of striated rootlets during ciliogenesis in quail oviduct.

In quail oviduct, a 175K (K = 10(3) Mr) protein associated with striated rootlets was previously identified by Klotz and co-workers using monoclonal antibody CC310. As this monoclonal antibody recognizes several proteins on immunoblots of ciliated cells, we prepared a polyclonal antibody monospecific to the 175K protein by intrasplenic immunization of mice. Immunofluorescence study confirmed the distribution of the 175K protein at the apical part of the ciliated cell and its absence in other epithelial cells.

Chromosomes of amphibian oocytes as a model for gene expression: significance of lampbrush loops.

Amphibian lampbrush chromosome loops exhibit morphological variability in their RNP matrix. The biological significance of such variability remains unknown. In order to approach this problem, the structural organization of each RNP matrix type was analyzed in relation to transcriptional and post-transcriptional processes.

1,25(OH)2D3 stimulates phospholipid biosynthesis and surfactant release in fetal rat lung explants.

Lung tissue from 18-day-old rat fetuses was cultured in the presence of 1,25-dihydroxyvitamin D3 - 1,25(OH)2D3 - (10(-9) M) and dexamethasone (10(-7) M) for 48 h. 1,25(OH)2D3 increased the lung content in phospholipids more specifically related to lung surfactant, phosphatidylcholine and phosphatidylglycerol. This increase was similar to that observed with dexamethasone.

Effects of the antiglucocorticoid RU 486 on the initiation of ultrastructural type-II cell differentiation in fetal rat lung.

The possible early role of endogenous glucocorticosteroids on the further ultra-structural development of the fetal rat lung epithelium was investigated in vitro using a potent antiglucocorticoid drug, RU 486. Lung primordia were explanted on day 13 of gestation and cultured for 4-6 days in the presence of fetal calf serum, with or without RU 486 in excess. The results obtained show that osmiophilic lamellar bodies specific for morphologically differentiated type-II cells did appear in a number of epithelial cells, even though the glucocorticosteroids possibly present in the culture medium, or transferred at explantation were antagonized by RU 486.

Relationship between vitamin D status and deposition of bound calcium in skeletal muscle of the rat.

The effects of vitamin D on the intramuscular distribution of total and bound calcium, phosphate and on available cytosolic calcium, were investigated in skeletal muscle. Total calcium and phosphorus were measured on ashed subcellular fractions of muscles from vitamin D-repleted and vitamin D-deprived rats. The variations in available calcium were followed by determining the activities of calcium-sensitive enzymes in isolated cytosol.

Effects of cold shock treatment on amphibian oocytes: alteration of heterogenous nuclear RNP morphology.

In cold-stressed oocytes of Pleurodeles waltl, lampbrush chromosome lateral loops exhibited important structural modifications which were visualized under light microscopy. Electron microscopy study revealed that the RNP particles associated with growing transcripts in the matrix of these loops were 15 nm at 8 degrees C compared to 30 nm at normal temperature (20 degrees C); hnRNP isolated from cold-stressed oocytes sedimented at 15 S in sucrose, while those from control oocytes sedimented at 30 S, as expected. However, under both normal and cold stress conditions, hnRNP possessed a buoyant density of 1.

Redistribution of fibronectin and keratin localization patterns in early wounded confluent PtK2 cells.

Single and double-label immunofluorescence were used to study the fibronectin (FN) and keratins (Ks) localization patterns in early wounded confluent PtK2 cells. A time-course study (0 hr, 2 hr, 6 hr and 24 hr) gives the following results: before wounding, the FN localizations of confluent cells are composed of curved and sometimes branched strands or fibrils. The Ks network is formed by radial fluorescent filaments connecting the Ks centers near the nuclei with a linear fluorescence underlying the cell membrane.

Effects of in vivo heat treatment on lampbrush chromosome structure in amphibian oocytes.

When Pleurodeles (Amphibian, Urodele) females were subjected to high temperatures (32-35 degrees C) for varying periods of time (45 min to 7 days), lampbrush chromosome structure underwent striking modifications. These changes included a numerical reduction in normal loops and progressive disorganization of RNP matrices of various loops. The degree of such disorganization was a function of the intensity and duration of the stress.

Cold-induced changes in amphibian oocytes.

Female Pleurodeles waltl newts (Amphibia, urodele), usually raised at 20 degrees C, were submitted to low temperatures; oocytes responded to this cold stress by drastic changes both in lampbrush chromosome structure and in protein pattern. Preexisting lateral loops of lampbrush chromosomes were reduced in size and number, while cold-induced loops which were tremendously developed, occurred on defined bivalents of the oocyte at constant, reproducible sites. A comparison of protein patterns in control and stressed oocytes showed two main differences: in stressed oocytes, overall protein synthesis was reduced, except for a set of polypeptides, the "cold-stress proteins"; second, there was a striking inversion of the relative amount of beta- and gamma-actin found in the oocyte nucleus before and after cold stress.

Immunological detection of spectrin during differentiation and in mature ciliated cells from quail oviduct.

A protein that was immunologically related to the erythrocyte and brain alpha-240-subunit and to the brain beta-235-subunit of spectrin was characterized by immunoblotting and was detected by immunofluorescence in the apical part of ciliated cells from quail oviduct. After immunogold-labeling electron immunocytochemistry, spectrin was detected mainly in a fibrillar meshwork located between the proximal parts of the basal bodies. It was also observed to be in contact with the basal foot of basal bodies, but was not found to be associated with the apical plasma membrane.

The highly concentrated liquid-crystalline phase of DNA is columnar hexagonal.

The DNA molecule is extremely compacted in bacteria, in cell nuclei, sperm heads and virus capsids. These interactions between DNA molecules are important to our understanding of chromatin condensation. DNA forms multiple liquid-crystalline phases whose nature depends on the polymer concentration, and it has been suggested that the highly concentrated phase of 50-nm DNA molecules is two-dimensionally ordered and smectic-like.

Application of the pyroantimonate method and electron probe microanalysis to the study of glycogen metabolism in liver.

Glycogen distribution in the liver of mouse under different metabolic conditions was studied by the pyroantimonate (PA) method combined with semi-quantitative electron probe microanalysis (EPMA). In the liver of animals subjected to a sugar-rich diet, glycogen granules were abundant and electron transparent. In fasted animals, they were less numerous and stained by PA, which indicates the presence of a complexed cation.

A method of isolation of apical membranous sheets from frog urinary bladder epithelium by stripping with gelatin.

We have developed a technique for recovering apical membranous sheets from amphibian urinary bladders by gelatin stripping. The tissue is mounted on a lucite support and the apical surface is first stuck onto a gelatin-coated glass slide at 30 degrees C. This sandwich is then chilled on ice and the bladder is pulled away from the slide.

Microtubules and actin microfilaments in the amphibian bladder granular cells.

Microtubules and microfilaments were localized by an immunocytochemical method in the granular cells of the frog bladder after fixation and isolation. An extensive array of microtubules was observed in the granular cells with an orientation towards the luminal plasma membrane in the supranuclear zone. Actin filaments formed a continuous bundle that underlined the cellular membrane.

Culture media conditioned by wounded cells modify the fibronectin localization pattern of unwounded confluent PtK2 cells.

A confluent PtK2 cell sheet was incised in a serum-free culture medium, at 15 min, 2 hr and 24 hr after wounding. The culture media were collected in the same way and used as conditioned media. Unwounded confluent cells were cultured in the conditioned medium for 24 hr.

Fibronectin network recovery in confluent PtK2 cells after acrylamide treatment.

Confluent PtK2 cells 4 hr treated with 5 mM acrylamide were FN-detected by indirect immunofluorescence. The initial fibrillar-FN network was replaced by an alveolar-type network located at the cell-cell contacts areas in the form of a thick frame with a lace-like appearance. Afterwards, acrylamide removal was obtained by several washes with fresh FCS-free culture medium.

Anti-fibronectin serum inhibits the disorganization of the dermal-epidermal junction in cultured wounded skin.

During wound-healing in cultured frog skin fragments, fibronectin (FN) was detected in the dermal-epidermal junction. Intracellular fibronectin was stained using permeabilization and DAB immunoperoxidase. With electron microscopy intracytoplasmic FN granules were localized in the epidermal processes of the stratum germinativum cells protruding towards the dermis and in their marginal regions (membrane-associated plaques).

An analog of Xenopus N1N2 protein in Pleurodeles waltl.

The oocyte nucleus of Pleurodeles waltl contains a major 185-kDa protein analog of Xenopus N1N2. Rabbit antibodies were raised against the 185-kDa protein. Affinity-purified antibody directed against the acid part (pI 4.

Modification of cell evagination and cell differentiation in quail oviduct hyperstimulated by progesterone.

Quail oviduct development is controlled by sex steroid hormones. Estrogen (E) induce cell proliferation, formation of tubular glands by epithelial cell evagination and cell differentiation. Progesterone (P) strongly increases the secretory process in E-treated quails, but inhibits cell proliferation, cell evagination and differentiation of ciliated cells.