bluuebunny/crossref_metadata_2025 huggingface dataset:
Decidualisation: origin and role of associated cells
Authors: Tarachand U.
Published: February 2012

Proliferation of peri‐ and subluminal stroma following a stimulus from the blastocyst leads to the appearance of decidual cells in the mammalian endometrium. Decidualisation can also be elicited by artificial stimuli in pseudopregnant animals. A variety of histophysiological reactions accompany decidualisation and distinct morphological features characterize decidual cells localized in the antimesometrial and mesometrial area. Granulated metrial gland cells, arising in the endometrium of decidualising uterus, form a separate class of cells and become prominent in the mesometrial triangle as pregnancy advances. This review deals with factors related to induction of decidualisation; structural characteristics of decidual and metrial gland cells; the origin and postulated roles of decidualisation‐associated cells. The functional role of decidual and metrial gland cells is discussed in relation to their structural complexity and recent observations on the haemopoietic origin of these cells.
Evidence for ionic coupling between MDCK cells at non‐confluent and confluent stages of culture
Authors: Giaume C. , Sahuquillo C. , Louvard D. , Korn H.
Published: February 2012

The possibility of current flow between epithelial cells (MDCK) has been evaluated using intracellular electrophysiological techniques. We report here that a significant electrotonic coupling was found in this material at all ages of culture. This observation contrasts with previous reports that confluent MDCK are not ionically coupled and lack gap junctions. Alternative mechanisms for such coupling are considered, with emphasis on the role of tight junctions, should the absence of gap junctions be confirmed.
Sites of aluminum accumulation in bone marrow: study using electron microscopy, ionic microscopy and X‐ray microanalysis
Authors: Watrin A. , Galle P.
Published: February 2012

Two methods of analytical microscopy have been used to study the distribution of aluminum in bone marrow of rats intoxicated by aluminum gluconate. Images of the distribution of aluminum in a field of 250 microns in diameter were obtained by analytical ion microscopy. They show that this element was concentrated in spots, associated with iron or alone, in the cytoplasm of some cells. Electron Probe Microanalysis (EPMA) has shown that aluminum concentration occurred in cells of the reticulo‐endothelial system, principally in the reticular cells of erythroblastic islets. In cells of the reticuloendothelial system, aluminum was observed in intracytoplasmic organelles having ultrastructural characteristics of lysosomes or phagolysosomes. In these organelles, aluminum is always associated with phosphorus and sometimes with iron. No cytoplasmic or nuclear aluminum accumulation was detected in any other variety of bone marrow cells. The consequences of the selective accumulation of aluminum in the cytoplasm of reticular cells of erythroblastic islets for the maturation of erythrocytes are discussed.
A morphometric study of subcellular responses in frog pituitary corticotropic cells to constant environmental conditions
Authors: Gracia‐Navarro F. , Garcia‐Navarro S. , Garcia‐Herdugo G.
Published: February 2012

Ultrastructural morphometry (point‐counting method) was used to evaluate stereological parameters of rough endoplasmic reticulum (RER), Golgi complex, secretory granules, mitochondria and lysosomes of Rana ridibunda pituitary corticotropic (ACTH) cells in animals subjected to constant environmental conditions (CEC) in relation to temperature and photoperiod. During this experiment, corticotropic cells are particularly sensitive to the effects of changes in environmental conditions in such a way that they course through a phase of RER and Golgi complex hypertrophy after 7 days on CEC and a phase of enhancement in the amount of secretory granules (the 11th day). After 15 days on CEC, the cells seemingly recuperate almost all the control evaluate parameters. These results strongly suggest that, in frog kept in captivity, ACTH cells play an important role in the acclimation process to new constant environmental conditions.
Quantification of calcitonin gene expression at the cellular level in medullary carcinoma of the thyroid
Authors: Nöel M. , Fragu P. , Calmettes C. , Jullienne A.
Published: February 2012

Calcitonin mRNA was detected in human medullary carcinoma using an in situ hybridization technique. This specific and reproducible method could lead to a better functional characterization of medullary carcinoma and should allow the definition of new prognosis factors in medullary thyroid cancer.
Forskolin stimulates cAMP production and the onset of the functional differentiation in the fetal rat thyroid in vitro
Authors: Pic P. , Michel‐Bechet M. , el Atiq F. , Athouel‐Haon A. M.
Published: February 2012

Forskolin, a diterpen stimulating the adenylcyclase induces in vitro an accumulation of cAMP in thyroid glands explanted from 17 day‐old rat fetuses. Thyroid glands from 15 day‐old fetuses exposed to forskolin exhibit, within 24 hr, an active folliculogenesis and 125I fixation in follicular cavities. The results indicate that cAMP probably activates the onset of both morphological and physiological maturation in the fetal rat thyroid.
Verapamil reduces glucose and fatty acid metabolism of beating and nonbeating rat heart cells
Authors: Miletich D. J. , Albrecht R. F. , Holshouser S. S.
Published: February 2012

The effects of various dosages of verapamil on glucose or fatty acid utilization by beating or nonbeating rat heart myocytes in tissue culture were determined. Myocytes were incubated with verapamil and either D‐6‐14C glucose or 1‐14C palmitic acid as substrate. After incubation the subsequently generated 14CO2 was captured with hyamine hydroxide and the equivalent oxygen values were calculated. Low doses of verapamil (50 ng/ml) treatment produced a 52% reduction in myocyte glucose utilization and a 16% reduction in fatty acid utilization that appeared to be independent of its effect on myocyte contractile rate since these effects were evident in both beating and nonbeating myocytes. In addition, verapamil treatment caused differences in the myocyte handling of substrate. Verapamil (50 ng/ml) lowered cellular accumulation of glucose by 21% compared to controls. Contrary to glucose, myocyte concentrations of palmitic acid were significantly increased by 117% relative to controls in verapamil treated cultures. These results suggest that verapamil may have a direct effect on basal heart cell metabolism in a way that is unrelated to myocyte contractile activity. In addition, verapamil may interfere with glucose membrane transport.
Role of a major cell‐substratum adhesion system in cell behavior and morphogenesis
Authors: Dufour S. , Duband J. L. , Thiéry J. P.
Published: February 2012

Fibronectins are multifunctional glycoproteins involved in the embryogenesis and in multiple physiological processes. Most of their functions derive from interactions of these glycoproteins with the cell surface. Fibronectin and their cell surface receptor constitute the major cell‐substratum adhesion that plays a key role in cell adhesion, cell spreading and cell motility, particularly during embryonic development. Additionally, other functions of fibronectins are due to their ability to ban a great variety of macromolecules contained in an extracellular matrix and in plasma. In particular, the interaction of fibronectins with the cell surface, collagen, fibrin and fibrinogen are involved in physiological processes such as hemostasis, wound healing and phagocytosis.
Ultrastructure of multilayered cultures of human gingival epithelial cells: attachment to enamel surfaces in vitro
Authors: Calle A. , Poly H. , Faure M. , Couble M. L. , Magloire H.
Published: February 2012

Human gingival cells were collected using an enzymatic procedure and seeded on a feeder layer of irradiated mouse 3T3 fibroblasts. Epithelial cells generate stratified colonies ultimately forming an epithelium which was studied using electron microscopy. When this epithelium‐like structure was dispased and transferred to enamel surfaces, the relationship between basal cells and enamel corresponded to half‐desmosomes and a discontinuous extracellular matrix.
Flow cytometry: technical description and some applications in France
Authors: Metezeau P. , Ratinaud M. H.
Published: February 2012

After reviewing basic technical considerations, we discuss some applications of flow cytometry in French laboratories. This methodology is used in several areas: oncology, cellular pharmacotoxicology, molecular biology and genetics, immunology, as well as cellular biology and physiology. We also examine the evolution of this technique in two directions: on the one hand, the appearance of increasingly sophisticated instruments; on the other, the development of less expensive and less complicated apparatuses principally directed at clinical applications.
Some applications of microspheres in flow cytometry
Authors: Miglierina R.
Published: February 2012

Microspheres of latex ranging from 0.1 to 10 microns in diameter are nowadays commercially available. Labelled with different fluorochromes, they are good standards to check the optical path and to calibrate flow cytometers. The kits available contain microspheres highly selected with a precise size and a narrow distribution, so as to allow an easy alignment of instruments. Mixed with the cell preparations, microspheres may be used as an internal standard, in order to compare samples from day to day. Phagocytic activity has been investigated after incubation of cells with fluorescent microspheres. Covalently bound to ligands such as antibodies, microspheres become a powerful and specific reagent to label cell surface antigens. The positive signal is enhanced, allowing the detection of poorly represented epitopes. This paper reviews some examples of these applications published in the flow cytometry field.
Effects of antineoplastic agents on the cell cycle progression
Authors: Charcosset J. Y.
Published: February 2012

Almost all antineoplastic drugs are able to delay—or block—cells in a particular phase of the cell cycle. Few clinically active drugs seem to interact with the G1‐states where cell growth can be arrested, although new compounds could be of interest with this respect. In contrast, most antineoplastic agents interact with DNA and/or DNA metabolism and have been shown to provoke a delay in G2. This could be the consequence of the DNA damage or of interference with controls which take place within the G2 phase.
Modulating effects of drugs on cell cycle kinetics
Authors: Ronot X. , Adolphe M.
Published: February 2012

The effects of individual drugs on cell cycle progression can often be determined by analyzing the DNA distribution of cultured cells at appropriate times after drug administration. In addition, to cell counts, RNA and/or protein content, the alterations in cell cycle distribution of drug‐treated cells can yield information on the potential cell cycle phase specificity of the drug. However single parameter DNA analysis, as currently used, can give inaccurate information when drug effects are associated with cytokinesis perturbations, in spite of various statistical and mathematical analyses. Scanning flow cytometry could be an interesting alternative for the detection of binucleate cells.
Flow cytogenetics
Authors: Bernheim A. , Miglierina R.
Published: February 2012

Classical cytogenetics is often tedious and many efforts have been made to develop other methods of chromosome analysis, among which flow karyotyping has recently emerged. Although less efficient than banding techniques to identify each chromosome, flow cytometry offers the opportunity of analyzing large quantities of chromosomes at a very high rate, resulting in a flow karyotype. Even if the initial aim of this technique, namely clinical diagnosis, has not been reached, another major application has emerged, namely chromosome sorting. This method is unique for isolating a set of purified chromosomes from most cells grown in culture in sufficient amount to perform experiments using molecular biology techniques. Significant results have been already obtained either through the construction of chromosome‐specific libraries or in the assignment of DNA probes to particular sorted chromosomes.
Estimation of the degradation of endocytosed material by flow cytofluorometry using two neoglycoproteins containing different numbers of fluorescein molecules
Authors: Midoux P. , Roche A. C. , Monsigny M.
Published: February 2012

The fluorescence properties of fluorescein bound to protein are used to quantitate by flow cytofluorometry the degradation of fluorescein‐labeled alpha‐glucosylated serum albumin (fluorescein‐labeled neoglycoprotein) after endocytosis by the membrane lectin of Lewis lung carcinoma cells (3LL cells). The quantum yield of fluorescein bound to a protein decreases when the number of fluorescein residues per protein molecule increases; however, after proteolytic digestion the mean fluorescence intensity of a fluorescein molecule is constant and equal to that of free fluorescein. The extent of the degradation of the endocytosed neoglycoprotein was determined with a flow cytofluorometer by using two neoglycoproteins containing either a small or a large number of fluorescein residues per neoglycoprotein molecule. At 4 degrees C, 3LL cells bind 750,000 molecules of fluorescein‐labeled alpha‐glucosylated serum albumin with an apparent binding constant of 2 × 10(6) 1 × mole‐1. At 37 degrees C, after 4 hr incubation 2.2 × 10(6) molecules of fluorescent alpha‐glucosylated serum albumin were cell‐associated, and of these at least one third were degraded.
Effects of denervation and direct electrical stimulation upon acetylcholine receptors and acetylcholinesterase accumulation in developing latissimus dorsi muscle of the chick
Authors: Khaskiye A.
Published: February 2012

The effects of denervation and of direct electrical stimulation of denervated muscle upon the acetylcholine receptor (AChR) clusters and acetylcholinesterase (AChE) spots in the fast avian muscle posterior latissimus dorsi have been investigated. Denervation at day 2 after hatching leads to a disappearance of the junctional AChR clusters and to a marked decrease of AChE spots. Direct electrical stimulation of denervated muscle allows the maintenance of AChR clusters and partly prevents the loss of AChE spots. When AChR cluster and post‐synaptic AChE have disappeared in a denervated muscle, muscle activity induced by direct stimulation is unable to induce their accumulation.
In vitro development of blastema cells in axolotl limb regeneration: effect of insulin and nerve extracts on cellular proliferation
Authors: Albert P. , Boilly B.
Published: February 2012

For the purpose of investigating the nature of the nervous factor which controls cell proliferation in limb blastema of Newts, we have cultured primary mesenchymous cells from limb blastemas of Axolotl. The cultures were carried out in Petri dishes (Primaria, Falcon) with a basal medium with contained diluted MEM supplemented with hormones (insulin, somatotropin, hydrocortisone and thyroxine). In this medium, the cells disperse from the explant from the 4th day of culture and begin to divide from the 7th day; 3 weeks later the culture begins to decline. During the course of culture, beginning at the 8th day, differentiation of myotubes and chondrogenesis occur. The mitotic index, measured on the 16th day after 48 hr of colchicine treatment, is about 1.6%. Addition of foetal calf serum to the basal medium favours cell migration and survival and stimulates proliferation (mitotic: index 6%); beef embryo extract has no effect on cell migration and a small effect on proliferation (mitotic index: 2.3%). Addition to the basal medium of insulin or nerve extracts (brain and spinal cord of adult newts, brain of 12 days chick embryos) 6 days before we measure the mitotic index stimulates proliferation in proportion to the dose, up to 6 times the mitotic index in basal medium. These results are discussed with respect to the problem of cell proliferation control during limb regeneration.
Phorbol esters as signal transducers and tumor promoters
Authors: Castagna M.
Published: February 2012

Extracellular ligands transfer information into the cell through various signaling pathways which operate in an integrated way. Oncogene proteins and tumor promoters cooperate to constitutively turn on the signaling pathways and lead to irreversible cell activation. The evidence that supports this concept is reviewed, with emphasis on the role of phorbol esters and protein kinase C in signal transduction and oncogenesis.
Modifications of the chromatin arrangement induced by ethidium bromide in isolated nuclei, analyzed by electron microscopy and flow cytometry
Authors: Santi P. , Papa S. , del Coco R. , Falcieri E. , Zini N. , Marinelli F. , Maraldi N. M.
Published: February 2012

Ethidium bromide (EB) is widely used for investigating the DNA conformation in chromatin both with conventional and cytofluorimetric techniques. Since the interaction of the dye with DNA should result in structural deformations which can be different in isolated or in situ chromatin, a study has been performed on the effects caused by different amounts of EB and the analogous propidium iodide on isolated nuclei, in which chromatin maintains its native relationships with the other nuclear structures (envelope, nucleolus, interchromatin RNP, nuclear matrix). The results obtained by comparing ultrastructural observations in thin sections and in freeze‐fracturing with conformational analysis in multiparameter flow cytometry indicate that the phenanthridinic fluorochromes, especially at the high concentrations used for cytofluorimetric analyses, cause deep rearrangements of the chromatin in situ. These effects consist both in aggregation and condensation of the fibers into the dense chromatin domains, and in an increase of the supernucleosomal configuration associated with an enlargement of interchromatin spaces in which the RNP particles appear particularly evident. These results, discussed with those available on isolated chromatin, suggest that any unwinding effect of the intercalating dyes on the DNA cause a general condensation of chromatin as a consequence of the constraints which characterize the organization of the chromatin inside the nucleus.
Primary muscle cells cultivated in medium conditioned by spinal cord cells show changes in messenger RNA as detected by translation in ovo accompanied by synthesis of extracellular matrix components
Authors: Schmid D. W. , de la Porte S. , Koenig J.
Published: February 2012

Primary muscle cell cultures were prepared from rat embryos and maintained in normal (unconditioned) and spinal cord (conditioned) media. In order to relate translational regulation to the morphological changes associated with each culture condition, mRNA was isolated from both culture variants and subjected to in ovo translation. Xenopus oocytes were injected with mRNA and their incubation media checked for the presence of newly formed proteins coded by the mRNAs and secreted into the medium. Electrophoretograms indicated mRNA‐dependent synthesis of several proteins in the molecular mass range of 30‐260 kD. To further characterize these proteins, antisera directed against several extracellular matrix proteins were used for immunoprecipitation: antigens recognized by anti‐heparan‐sulfate‐proteoglycan and anti‐fibronectin were enhanced in conditioned cells, whereas laminin was found to be reduced.
In situ localization of soluble and filamentous actin in Torpedo marmorata electrocyte
Authors: Kordeli E. , Cartaud J. , Nghiêm H. O. , Changeux J. P.
Published: February 2012

The subcellular distribution of soluble and filamentous forms of actin in Torpedo marmorata electrocyte was investigated by cytochemical methods. Under conditions of adequate fixation of the electric tissue, two different monoclonal anti‐actin antibodies revealed, in situ, actin only in the cytoplasm, never in association with the innervated and non‐innervated membranes. On the other hand, a fluorescent derivative of phalloidin labeled the polymerized F‐form of actin at the level of the non‐innervated membrane and of the nerve terminals. However, after homogenization of the tissue, innervated membrane fragments, which still comprised cytoskeletal filaments, were systematically labeled on their cytoplasmic face. In these membrane fragments, cytoplasmic actin was never observed on the cytoskeleton. These results point to a redistribution of actin during tissue fractionation. The secondary binding of actin to the cytoplasmic surface of the postsynaptic membrane is consistent with its known in vitro interaction with the membrane‐bound, 43 kd (v1) protein. Thus, at variance with the 43 kd protein, actin is not a prominent component of the mature Torpedo postsynaptic domain, and its suggested contribution to the stabilization of the AchR in the postsynaptic membrane should be reconsidered.
Growth of animal cells on microbeads. II. Estimation of biomass in situ and observation of cytopathic effects after infection of McCoy cells with Chlamydia trachomatis
Authors: Hanotte O. , Dejaiffe C. , Dubois D. , Vanderpoorten P. , Menozzi F. , Miller A. O.
Published: February 2012

The Channelyzer C256 together with the ZB Coulter Counter have been used to study in situ the growth kinetics of McCoy cells attached on Cytodex 3 microbeads. The number of cells per microbead varied linearly with the average size of the covered microbeads, showing that electronic particle sizing can be used to measure biomass or cell numbers. As the cells became confluent, an increase in cell volume with little accompanying increase in cell number was detected. The technique also enables the experimenter to follow in situ the development of cytopathic effects resulting from the infection by pathogens such as Chlamydia trachomatis serotype L1.
Crystallographic study of the ferritin molecule: new results obtained from natural crystals in situ (mollusc oocyte) and from isolated molecules (horse spleen)
Authors: Quintana C. , Bonnet N. , Jeantet A. Y. , Chemelle P.
Published: February 2012

The aim of the present work is to gather new information on the ferritin molecule. Natural crystals of ferritin occurring in the yolk platelets of a mollusc oocyte were studied. Their crystallographic structure was found to be equivalent to one of the structures obtained by artificial crystallization (fcc; a = 15 nm). Individual ferritin particles isolated from horse spleen were studied by microdiffraction techniques, using field emission gun transmission electron microscopy. The iron core crystals display a hexagonal structure; our results confirm the value of the unit cell parameter a (0.51 nm) and, for the first time, we have been able to extract the value of the unit cell parameter c (0.95 nm). Thus, among the three models described in the literature for the crystalline structure of the iron complex, our results corroborate that of Towe and Bradley (J. Colloid. Interf. Sci., 1967, 25, 384‐392).
In vitro effects of calcium phosphate biomaterials on fibroblastic cell behavior
Authors: Gregoire M. , Orly I. , Kerebel L. M. , Kerebel B.
Published: February 2012

The effect of synthetic granular hydroxyapatite (HAP) on cultured fibroblastic cells (L929, human bone and gingiva cells) was studied. Phagocytosis of HAP particles and resulting morphological cell changes were demonstrated by microscopic examinations. Cell counts and [3H]thymidine uptake indicated significant increases in cell proliferation and DNA synthesis. These results could account for some of the alterations of the fibroblast behavior induced by changes in intracellular levels of calcium ions released from the material.
Localization of basement membrane glycoproteins in rat kidney during foetal development
Authors: Cheignon M. , Bakala H. , Cornet S. , Djaziri R. , Schaeverbeke J.
Published: February 2012

The distribution of basement membrane glycoproteins (type IV collagen, laminin, fibronectin, and proteoglycans) was studied in foetal rat kidney by immunohistochemical techniques using polyclonal antibodies. From the first stages of nephron differentiation, all these glycoproteins were detectable by immunofluorescence in the tubular and glomerular basement membranes and in the mesangial matrix. As differentiation proceeded, labelling of glycoproteins progressively intensified, except for that of fibronectin, which gradually decreased in the glomerular basement membrane (GBM) and was barely observable at full differentiation. With immunoperoxidase staining in electron microscopy, all glycoproteins were seen to be widely dispersed in the spaces between the epithelial and endothelial glomerular cells so long as the GBM remained a loose structure. However, after it became a compact, 3‐layered formation, type IV collagen and laminin were distributed throughout the GBM, whereas proteoglycans and anionic sites appeared as 2 rows of granules confined to the laminae rarae.
Tridimensional structure of the Golgi apparatus of nonciliated epithelial cells of the ductuli efferentes in rat: an electron microscope stereoscopic study
Authors: Rambourg A. , Clermont Y. , Hermo L. , Segretain D.
Published: February 2012

The 3‐dimensional structure of the Golgi apparatus has been analyzed in thin and thick sections of nonciliated epithelial cells of ductuli efferentes of rat by use of low‐ and high‐voltage electron microscopes and a stereoscopic approach. In thick sections of tissue impregnated with osmium, the Golgi apparatus appeared at low magnification as a continuous network forming a corona at the apical pole of the nucleus. At higher magnification and in thin sections of tissue postfixed with reduced osmium and stained with lead citrate or treated to demonstrate phosphatase activity, the following structural features were observed. In the longitudinal axis of the Golgi network there were alternating compact and noncompact zones. The compact zones were composed of 6‐8 flattened, poorly fenestrated saccules in close apposition to each other and forming stacks. The noncompact zones were composed of a number of highly fenestrated and slightly distended saccules, which were continuous with and bridged the saccules of the compact zones. In the cis‐trans axis of the Golgi apparatus the following compartments were observed: (a) On the cis face there was a continuous osmiophilic tubular network referred to as the cis element; (b) a cis compartment composed of 3 or 4 NADPase‐positive saccules perforated with pores in register forming wells that contained small vesicles; (c) a trans compartment composed of 1 or 2 TPPAse‐positive elements underlying the NADPase ones, followed by 1 or 2 CMPase‐positive elements that showed a flattened saccular part continuous with a network of anastomotic tubules. These tubular networks curved away from the overlying elements, giving these elements a “peeling‐off” configuration. These elements referred to as sacculotubular elements were discontinuous along the Golgi network. This compartment also included shriveled trans‐tubular networks detached from the overlying sacculotubular elements and seemingly undergoing fragmentation into vesicles and tubules. The structural features of the elements of the trans compartment were indicative of continuous renewal.
Stress response in Drosophila subobscura. II. Puff activity during anoxia and recovery from anoxia
Authors: Arbona M. , De Frutos R.
Published: February 2012

When individuals of Drosophila subobscura at 0 hr prepupa are submitted to anoxia (4 hr and 24 hr, respectively), their puffing pattern is very similar to that shown by individuals at the moment of development in which treatment began. The same expression of genes (the same puffing pattern and the same protein pattern) is induced in this species by recovery from anoxia as well as by heat shock treatment at 31 degrees C.
Ultrastructural and cytochemical characterization of subcellular fraction of plasmalemmal origin obtained from uterine longitudinal smooth muscle
Authors: Lalanne C. , Duvert M. , Sarger C. , Salat C. , Chevallier J.
Published: February 2012

The role of Ca2+‐ATPase as the driving force for active calcium uptake, involved in the relaxation of smooth muscle, was studied. It was shown by immunocytochemistry that Ca2+‐ATPase activity was localized at the plasma membrane level of longitudinal smooth muscle of pregnant rat uteri (18‐20 days). To study calcium regulation in uterine longitudinal smooth muscle, 2 microsomal fractions (F1 and F2) were obtained, enriched in plasma membrane material (Lalanne et al., 1984, in: Calcium Regulation in Smooth Muscles. INSERM series, 124, pp. 283‐292). In the present paper this material is characterized at both morphologic and cytochemical levels. Both fractions are ultrastructurally heterogeneous: (a) thin sections clearly show 2 populations that differ in vesicular shape and size; (b) negative staining also shows differences in membrane structure, which could be related to biochemical differences and/or to the well known heterogeneity of the plasma membrane. Two reactions (PATAg and concanavalin A‐biotin‐avidin‐ferritin), allowing visualization of cell coat glycans, were performed on F1 and F2 and on thin sections of longitudinal smooth muscle. Plasma membrane and almost all the vesicles of F1 and F2 are reactive. It is concluded that these 2 fractions are characteristic enough for studying, at the molecular level, the ability of plasma membrane to control calcium circulation in uterine smooth muscle.
Soluble cytokeratins in Xenopus laevis oocytes and eggs
Authors: Gall L. , Karsenti E.
Published: February 2012

Xenopus oocytes contain a radial network of cytokeratins which seems to fragment during meiosis reinitiation (maturation). The mature egg contains only a cortical network of cytokeratins. We have looked for the presence of soluble cytokeratins in oocytes and unfertilized eggs and have found them in both cases. However, the proportion of soluble to insoluble cytokeratins is slightly higher in the egg than in the oocyte. Soluble cytokeratins incorporate 35S‐methionine at a high rate in the oocyte but to a lesser extent in the egg. This suggests that they are biosynthetic intermediates in the oocyte. In the egg, at least a fraction of the soluble cytokeratins may arise from the fragmentation of the polymer which seems to occur during the maturation process. Insoluble cytokeratins are strongly labeled with 32P both in oocytes and eggs. On the other hand only the soluble keratins of the egg incorporate 32P. Since the isoelectric point of soluble and insoluble cytokeratins is the same in oocytes and eggs, their absolute level of phosphorylation probably remains relatively constant. This suggests that: i) phosphate turnover is very slow in oocyte soluble cytokeratins, ii) phosphorylation is not a major way of changing the structural state of cytokeratins in amphibian oocytes and eggs.
Effects of estramustine, a new anti‐microtubule drug, on the induction of casein gene expression by prolactin
Authors: Zwierzchowski L. , Flechon J. , Ollivier‐Bousquet M. , Houdebine L. M.
Published: February 2012

Estramustine, a new anti‐microtubule drug, was added to the culture medium of rabbit mammary explants with lactogenic hormones. In the absence of the drug, prolactin with insulin and cortisol stimulated DNA synthesis and it induced beta‐casein and beta‐casein mRNA accumulation in the tissue. As opposed to other anti‐microtubule agents such as colchicine, estramustine was unable to prevent prolactin actions. An examination of the mammary cells by immunofluorescence revealed that the microtubule network was significantly altered under the influence of estramustine. These data indicate that the integrity of microtubules is not required for prolactin to deliver its message to the mammary cell. These data also suggest that other anti‐microtubule drugs such as colchicine which prevent prolactin action act through their binding to tubulin molecule unrelated to microtubule structures.
The occurrence of metals Al, Fe, Ni, Cu, Zn in the nuclei of animal cells: an ultrastructural, in situ, X‐ray microanalytical study
Authors: Quintana C. , Olmedilla A. , Antoine N. , Ollacarizqueta A.
Published: February 2012

Cell nuclei may contain significant quantities of the metals Fe, Ni, Cu, Zn, since they are present in the nucleo‐enzymes and/or nucleic acids. These metals have been detected by X‐ray microanalysis in situ in dinoflagellates (Kearns et al). Aluminum was only detected in cell nuclei in cases of natural or provoked intoxication. We observed at the ultrastructural level, in situ, the presence of Al, Fe, Ni, Cu, Zn in nuclei of different types of non‐intoxicated animal cells. Moreover, we measured the concentration of these metals in the nucleolus and chromatin and compared it with the concentration of P and S.
The energetic growth yields of the yeast Candida parapsilosis
Authors: Camougrand N. , Velours G. , Guerin M.
Published: February 2012

The energetic growth yields of Candida parapsilosis were compared with those of Saccharomyces cerevisiae as a function of the energy source in the presence or absence of antimycin A, an inhibitor of the second phosphorylation site. When glycerol was used as energy source, the energetic growth yields were quite similar in C. parapsilosis and S. cerevisiae. On the other hand, when experiments were carried out with glucose as energy source, although three phosphorylation sites were available, glucose was found to be a poor energy source for C. parapsilosis. When C. parapsilosis was grown in the presence of antimycin A, on glucose: YGluS = 3YGlu + AS and on glycerol: YGlyS = 2 YGly + AS. It was concluded that growth in the presence of antimycin A could occur due to the functioning of the third phosphorylation site. This result agrees with previous works indicating that in C. parapsilosis the alternative pathway merges into the main respiratory chain at the cytochrome c level. Although the doubling time of C. parapsilosis was much less temperature‐sensitive than that of S. cerevisiae, the energetic growth yield was the same at 13 degrees C and 28 degrees C, and consequently, the secondary pathway did not seem to be thermogenic.
Ultrastructural localization of concanavalin A receptors in the plasma membrane: association with underlying actin filaments
Authors: KATSUMOTO Tetsuo , KURIMURA Takashi
Published: February 2012

Whole‐mount cell preparations of cultured rat 3Y1 cells were examined by stereo electron microscopy to identify the ultrastructural localization of concanavalin A (Con A) receptors in the plasma membrane, and to clarify the relationship between Con A receptors and cytoskeletal components. Well spread monolayer cells were extracted with saponin, briefly fixed, and then partially broken open with shearing force to facilitate the introduction of antibodies for identification of actin filaments. Stereo electron microscopy of such treated cells revealed a 3‐dimensional image of filamentous structures such as fine filaments, microtubules (MT) and endoplasmic reticulum (ER) in the flattened areas of each cell. Just beneath the plasma membrane were meshworks of actin‐containing fine filaments, as identified by an immunogold staining method. Microtubules and ER were observed to be either directly or indirectly associated with this meshwork. The broken open part of each cell exhibited a meshwork of filaments which were associated with the cytoplasmic surface of the plasma membrane. Some of the filaments were connected to the plasma membrane either by their ends or by their lateral surfaces. The localization of Con A receptors was examined by binding colloidal gold‐labelled Con A to the surface of fixed, saponin‐extracted cells. Virtually all gold particles bound externally at the same membrane sites where intracellular actin filaments attached internally. The observations strongly suggest that the distribution of Con A receptors was regulated by the underlying meshwork of actin filaments.
Anti‐bromodeoxyuridine monoclonal antibody: An alternative tool for the identification of replicated DNA at the electron microscope level
Authors: Thiry Marc , Dombrowicz David
Published: February 2012

A new method for identifying the replicated DNA at the electron microscope level is described. Cells were first exposed in vitro to 5‐bromodeoxyuridine (BUdR) in conjunction with 5‐fluorodeoxyuridine (FUdR) and BUdR incorporated into DNA was then detected on Lowicryl‐embedded sections by immunogold technique using a monoclonal anti‐BUdR antibody. After using this method, chromatin and chromosomes are strongly labelled.
Polarity reversal of inside‐out thyroid follicles cultured within collagen gel: structure of the junctions assessed by freeze‐fracture and lanthanum permeability
Authors: Barriere Hélène , Chambard Marianne , Selzner Jean‐Pierre , Mauchamp Jean , Gabrion Jacqueline
Published: February 2012

The organization of tight junctional complexes (TJs) was studied in cultured porcine thyroid cells during the inversion of polarity induced by collagen‐embedding of inside‐out follicles, using freeze‐fracture replicas and lanthanum penetration. During the early steps of polarity reversal, freeze‐fractures showed that TJs generally persisted. They increased in width and progressively branched out into the basolateral surfaces, towards the basal pole. Later, the number of TJ strands decreased and gap junctions inserted within TJ networks were found between cells in reversed follicles, in the same manner as in typically polarized follicles, embedded in collagen or in suspension. The de novo formation of TJ complexes was rarely found in the reversing structures. Despite the heterogeneity of TJs assessed by freeze‐fracture, impermeability to lanthanum tracer was noted in inside‐out structures. During the reversal process, some TJs remained unstained, whereas others displayed permeability to lanthanum. This heterogeneity might be due to the ≪opening≫ of a small number of junctions (perhaps only one by aggregate). When the process was achieved after 48 hr in collagen, the tightness of the junctions was complete, confirmed by the absence of lanthanum in luminal cavities of newly formed follicles.
Human serum reacting specifically with a subset of β‐tubulin isoforms
Authors: Edde Bernard , Vandaele Sylvie , Darmon Michel , Soubiran Pierre
Published: February 2012

The serum of a patient suffering from myeloma was found to decorate microtubules and mitotic spindles of cultured cells. Immunoblots performed after one‐ and two‐dimensional electrophoresis showed a reaction with a certain subset of β‐tubulin isoforms, but not with β′‐ and α‐tubulins. The tubulin subset contained both ubiquitous (β‐3) and neurospecific (β‐4,5,6) isoforms.

An IgM lambda and an IgA kappa myeloma protein were found in this serum. Immunoblots performed with specific anti‐isotype second antibodies showed that the tubulin subset could be evidenced using anti‐mu, alpha, lambda, and kappa‐specific antisera. Moreover, the tubulin subset was also evidenced using an anti‐gamma second antibody. These results, which do not exclude a participation of the myeloma proteins in the anti‐tubulin reactivity, indicate, however, that the antibody response was polyclonal. The same restricted specificity of all classes of anti‐tubulin antibodies of this serum favours the hypothesis that the immune response of the patient was directed against an antigen sharing epitopes with tubulin rather than with tubulin itself.
Quantitative ultrastructural study of nucleolus‐organizing regions at some stages of the cell cycle (G0 period, G2 period, mitosis)
Authors: Zatsepina O. , Hozak P. , Babadjanyan D. , Chentsov Y.
Published: February 2012

The quantitative characteristics of chromosomal nucleolus‐organizing regions (NORs) and some other nucleolar components were studied on ultra‐thin sections of pig embryo kidney cells (PK cells). It was shown that: 1) nucleoli‐per‐cell volumes were 3 times smaller in the G0 period than in the G2 period; 2) the number of fibrillar centers (FCs) per cell in the G0 period, the G2 period, and at metaphase was equal to 7, 33.7, and 8, respectively; 3) mean volumes of individual FCs in the G0 period (0.033±0.005 μm 3), G2 period (0.014±0.001 μm 3), and at metaphase (0.04±0.05 μ3) were significantly different; 4) the total volumes of FCs calculated per haploid set of chromosomes were practically the same in the G0 (0.105 μm3) and G2 (0.107 μm3) periods, but were twice as large as those at metaphase (0.04–0.05 μm3). These data show that partial activation and inactivation of ribosomal genes in interphase PK cells are not accompanied by a considerable change in the total volume of FCs and may be due to the fragmentation and fusion of individual FCs. Complete inactivation of ribosomal genes in mitosis results in a decrease of total volumes of FCs per cell; 5) in G0 and G2 periods the total volume of the dense fibrillar component per nucleolus is practically proportional to the nucleolus volume (r = 0.99);6) in the G2 period, the nucleolus volume is also proportional to the number of FCs (r = 0.99;7) the volume of the dense fibrillar component within individual fibrillar complexes is not a constant one. This is indirect evidence for a different level of NOR functional activity in different NO‐chromosomes at interphase.
Immunocytochemical localisation of GABA in endocrine cells of the rat entero‐pancreatic system
Authors: Gilon Patrick , Campistron Ghislaine , Geffard Michel , Remacle Claude
Published: February 2012

The occurence of GABA‐containing cells in the rat entero‐pancreatic system was investigated by using anti‐GABA‐glutaraldehyde antibodies at the light and electron microscope level. In the pancreas, the B cells showed intense immunoreactivity, contrary to non‐B and exocrine cells. Moreover, post‐embedding immunogold staining was localised mostly in mitochondria, close to rough endoplasmic reticulum and in the nucleus. The insulin granules appeared non‐significantly stained, which suggests the lack of cosecretion of GABA together with insulin. In the duodenum, GABA immunoreactivity was detected in certain endocrine cell types, suggesting a possible interaction with this amino acid. The well established GABAergic innervation in the enteric system was also confirmed by immunolabelling.
Growth of normal and neoplastic rat pleural mesothelial cells in the presence of conditioned medium from neoplastic mesothelial cells
Authors: Van der Meeren Anne , Levy Françoise , Bignon Jean , Jaurand Marie‐Claude
Published: February 2012

Several transformed cells have been demonstrated to secrete growth factors. We studied the effect of conditioned medium from neoplastic rat pleural mesothelial cells on normal and neoplastic mesothelial cell growth. The results showed that the concentrated conditioned medium stimulated neoplastic mesothelial cell growth but inhibited reversibly normal mesothelial cell growth.
The development of a large nucleolus during oogenesis in Acanthocyclops vernalis (Crustacea, copepoda) and its possible relationship to chromatin diminution
Authors: Standiford David M.
Published: February 2012

The development of a single, very large (25–35 μm diameter) nucleolus during oogenesis in the crustacean Acanthocyclops vernalis is described. The nucleolus is the site of ribosomal RNA production the egg, as shown by in situ hybridization, and apparently the only source, as accessory cells are not observed. Ribosomal DNA amplification, as manifested by the presence of multiple nucleoli, is also not observed. Silver staining and C‐banding suggest that chromosomal regions other than the nucleolar organizer are involved with the elaboration of the nucleolus. These observations, along with what is known about the nature of the DNA lost during the developmental process of chromatin diminution in this organism, suggest a relationship between the large oocyte nucleolus and the DNA lost during diminution.
Starfish acrosomal acid phosphatase: a cytochemical and biochemical study
Authors: Sousa Mário , Ferreira Pedro Moradas , Amorim António , Azevedo Carlos
Published: February 2012

The acrosome reaction of spermatozoa from the starfish Marthasterias glacialis was induced with the ionophore A23187. Reacted cells were then processed for acid phosphatase ultrastructural cytochemistry, but significant enzyme activity was not detected. However, when the supernates from suspensions of ionophore‐treated sperm were assayed for acid phosphatase, a net enzyme activity was observed. Supernatant proteins were run in starch gel electrophoresis and fluorescent zymograms revealed a single band of acid phosphatase. SDS‐PAGE of proteins eluted from the active spots of starch gels showed one major band of about 63 kDa. The results obtained support the hypothesis that the acid phosphatase whose activity has been detected only at the time of binding of sperm and egg originates from the sperm acrosome.
Vasopressin modifies osmium impregnation of the endoplasmic reticulum in cultured kidney collecting duct cells
Authors: Denis Gustave , Akbarieh Marc , Bergeron Michel
Published: February 2012

The ultrastructure of collecting duct epithelia was studied with the osmium impregnation technique in renal cortical explants grown in culture in the form of globular bodies. When this technique was applied to 7‐day‐old globular bodies, the endoplasmic reticulum (ER) of the superficial layer cells was faintly impregnated in the presence or absence of arginine‐vasopressin (AVP) in the incubation medium; the ER of the cells located in the core of the globular bodies was densely impregnated with osmium. When these globular bodies were sectioned in 2 fragments and one was incubated in AVP for 30 min while the other was used as a control, a marked increase in osmium impregnation occurred: osmium black deposits were then noted in the lumen of the endoplasmic reticulum of two‐thirds of the cells in the superficial layer. Various patterns of impregnation were observed. Cryptlike formations gave rise to mature epithelial cells showing the same pattern of osmium impregnation. When cyclic adenosine monophosphate (cAMP) was substituted for AVP in the incubation medium, the treated globular bodies revealed the same ultrastructural characteristics. Our data suggest that this primary culture of collecting duct epithelia is made up of heterogeneous cells with characteristics of principal and intercalated cells and that the AVP has a stimulatory effect on ER maturation, which is mediated by the adenylate cyclase system.
Degradation of yolk in the brine shrimp Artemia. Biochemical and morphological studies on the involvement of the lysosomal system
Authors: Perona Rosario , Bés Jean‐Claude , Vallejo Carmen G.
Published: February 2012

The degradation of yolk granules during the development of Artemia was studied. The results obtained suggest that lysosomes are involved in the process. In homogenates of embryos and larvae at different stages of development, the distribution of 2 lysosomal markers, acid phosphatase and cathepsin B, was studied by sucrose isopycnic gradient centrifugation. Three peaks of enzyme activity of densities > 1.3 and around 1.25 and 1.18 were observed. As revealed by electron microscope analysis, the 3 peaks were found to be associated with increasingly degraded yolk structures which stained for acid phosphatase. The process can be mimicked in vitro by incubating isolated yolk granules and lysosomes. The enzyme activity levels of the 3 peaks observed during development presented an oscillatory pattern, suggesting that degradation of yolk is cyclic. Five cycles of degradation were observed during the initial 60 hr of development.