Musciomol and flunitrazepam binding sites in a subcellular fraction enriched in rat cerebellar glomeruli

1992 ◽  
Vol 17 (7) ◽  
pp. 683-686
Author(s):  
F. Viennot ◽  
B. Foucaud ◽  
G. Gombos
Keyword(s):  
Binding Sites ◽  
Subcellular Fraction ◽  
Cerebellar Glomeruli

scholarly journals Purification of an inositol 1,4,5-trisphosphate-binding calreticulin-containing intracellular compartment of HL-60 cells

1992 ◽  
Vol 281 (3) ◽  
pp. 651-656 ◽  
Author(s):  
C Van Delden ◽  
C Favre ◽  
A Spät ◽  
E Cerny ◽  
K H Krause ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Storage Protein ◽  
Binding Sites ◽  
Subcellular Fraction ◽  
Sucrose Density Gradient ◽  
Subcellular Fractions ◽  
Differential Centrifugation ◽  
Similar Extent ◽  
Inositol 1,4,5 Trisphosphate

To investigate the identity of Ins(1,4,5)P3-sensitive intracellular Ca2+ stores in myeloid cells, we have developed a method that yields subcellular fractions highly enriched in Ins(1,4,5)P3 binding. HL-60 cells were disrupted by nitrogen cavitation, and subcellular fractions were obtained by differential centrifugation, followed by Percoll- and sucrose-density-gradient separations. A subcellular fraction enriched 26-fold in Ins(1,4,5)P3-binding sites was obtained. This fraction showed no enrichment in plasma-membrane markers and only a comparatively moderate enrichment (7-fold) in endoplasmic-reticulum markers. The ratio between specific enrichment of Ins(1,4,5)P3 binding and endoplasmic-reticulum markers in the different fractions varied over 50-fold, from less than 0.1 to greater than 5. The purified Ins(1,4,5)P3-binding fraction was enriched to a similar extent (27-fold) in the putative intravesicular Ca(2+)-storage protein calreticulin. Our results favour the concept of a distinct Ins(1,4,5)P3-binding, calreticulin-containing compartment (i.e. the calciosome) in HL-60 cells.

[3 H]Naloxone binding sites in porcine ovarian follicles and corpora lutea during the ovarian cycle

1995 ◽  
Vol 132 (5) ◽  
pp. 622-626 ◽  
Author(s):  
Hiroko Hamada ◽  
Shiroh Kishioka ◽  
Mareo Yamoto ◽  
Ryosuke Nakano
Keyword(s):  
Opioid Receptors ◽  
Granulosa Cells ◽  
Binding Sites ◽  
Subcellular Fraction ◽  
Specific Binding ◽  
Ovarian Follicles ◽  
Ovarian Cycle ◽  
Corpora Lutea ◽  
Follicular Maturation ◽  
Porcine Granulosa Cells

Hamada H, Kishioka S, Yamoto M, Nakano R. [3H]Naloxone binding sites in porcine ovarian follicles and corpora lutea during the ovarian cycle. Eur J Endocrinol 1995;132:622–6. ISSN 0804–4643 We demonstrated the presence of opioid receptors in the porcine ovary using [3 H]naloxone. We also examined the change in the number of opioid receptors during follicular maturation. In addition, we found specific binding of [3H]naloxone in the porcine ovary using naloxone, β-endorphin, methionine-enkephalin and dynorphin. The binding of [3H]naloxone to porcine granulosa cells and the 2000-g subcellular fraction of corpora lutea was examined to demonstrate the presence of specific [3H]naloxone binding in the porcine ovary. Binding of [3H]naloxone to porcine granulosa cells was displaced by cold naloxone and β-endorphin but not by dynorphin and methionine-enkephalin. A similar phenomenon was also demonstrated in the 2000 g subcellular fraction of porcine corpora lutea. However, Scatchard analyses revealed a single class of high-affinity (Kd = 28.5 × 10−9 mol/l) and low-capacity binding sites (Bmax = 30.5 fmol/5 × 106 cells) in porcine granulosa cells. Similar binding parameters were obtained in the 2000-g subcellular fraction of porcine luteal tissue (Kd = 28.3 × 10−9 mol/l, Bmax = 59.3 nmol/kg protein). [3H]Naloxone binding sites in the porcine ovary showed binding characteristics similar to those of opioid receptors in other organs like brain, uterus and placenta. Furthermore, we demonstrated that the specific binding sites of [3H]naloxone in porcine granulosa cells decreased during follicular maturation. Opioid receptors have been detected in the uterus, placenta and Sertoli cell cultures in some species. However, there is no detailed study on opioid receptors in granulosa cells and luteal tissues in any species. Our data suggest a relationship between folliculogenesis and ovarian opioid peptides. The opioid system may participate in the regulation of follicular maturation. Hiroko Hamada, Department of Obstetrics and Gynecology, Shichibancho 27, Wakayama 640, Japan

Indomethacin inhibits the effects of oestrogen in the anterior pituitary gland of the rat

1989 ◽  
Vol 121 (3) ◽  
pp. 513-519 ◽  
Author(s):  
D. G. Rosental ◽  
G. A. Machiavelli ◽  
A. C. Cherñavsky ◽  
N. Sterin Speziale ◽  
J. A. Burdman
Keyword(s):  
Pituitary Gland ◽  
Binding Sites ◽  
Anterior Pituitary ◽  
Subcellular Fraction ◽  
Culture Media ◽  
Biological Effects ◽  
Prostaglandin Synthesis ◽  
Anterior Pituitary Gland ◽  
Prostaglandin F ◽  
Prolactin Synthesis

ABSTRACT Two inhibitors of prostaglandin synthesis, indomethacin and aspirin, blocked the increase of oestrogen-binding sites in the nuclear subcellular fraction, an increase which occurs after the administration of oestradiol. Consequently the biological effects of oestrogens in the anterior pituitary gland of the rat (prolactin synthesis, concentration of progesteronebinding sites and cell proliferation) are diminished. The anterior pituitary gland synthesized prostaglandin F2α (PGF2α), PGE2 and PGD2 from arachidonic acid. This synthesis was blocked when indomethacin was added to the culture media. Oestrogen increased the concentration of PGE2: an increase that was partially prevented by indomethacin. Prostaglandins may have an important role on the effects of oestrogen in the anterior pituitary gland of the rat. Journal of Endocrinology (1989) 121, 513–519

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

Sites of Insulin Action Using Ferritin Labeling

1971 ◽  
Vol 29 ◽  
pp. 540-541
Author(s):  
Burton B. Silver ◽  
Ronald S. Nelson
Keyword(s):  
Electron Microscopy ◽  
Binding Sites ◽  
Anterior Pituitary ◽  
Insulin Action ◽  
Diabetic Rats ◽  
Insulin Antibody ◽  
Fat Pad ◽  
Target Organs ◽  
Uranium Salts ◽  
Sugar Levels

Some investigators feel that insulin does not enter cells but exerts its influence in some manner on the cell surface. Ferritin labeling of insulin and insulin antibody was used to determine if binding sites of insulin to specific target organs could be seen with electron microscopy.Alloxanized rats were considered diabetic if blood sugar levels were in excess of 300 mg %. Test reagents included ferritin, ferritin labeled insulin, and ferritin labeled insulin antibody. Target organs examined were were diaphragm, kidney, gastrocnemius, fat pad, liver and anterior pituitary. Reagents were administered through the left common carotid. Survival time was at least one hour in test animals. Tissue incubation studies were also done in normal as well as diabetic rats. Specimens were fixed in gluteraldehyde and osmium followed by staining with lead and uranium salts. Some tissues were not stained.

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Lectin Binding Studies on RNA Tumor Virus-Infected Cells

1975 ◽  
Vol 33 ◽  
pp. 326-327
Author(s):  
D. C. Hixson
Keyword(s):  
Binding Sites ◽  
Lectin Binding ◽  
Culture Conditions ◽  
3T3 Cells ◽  
Binding Studies ◽  
Con A ◽  
Microscopic Studies ◽  
Tumor Virus ◽  
Infected Cells ◽  
Cell Culture Conditions

The abilities of plant lectins to preferentially agglutinate malignant cells and to bind to specific monosaccharide or oligosaccharide sequences of glycoproteins and glycolipids make them a new and important biochemical probe for investigating alterations in plasma membrane structure which may result from malignant transformation. Electron and light microscopic studies have demonstrated clustered binding sites on surfaces of SV40-infected or tryp- sinized 3T3 cells when labeled with concanavalin A (con A). No clustering of con A binding sites was observed in normal 3T3 cells. It has been proposed that topological rearrangement of lectin binding sites into clusters enables con A to agglutinate SV40-infected or trypsinized 3T3 cells (1). However, observations by other investigators have not been consistent with this proposal (2) perhaps due to differences in reagents used, cell culture conditions, or labeling techniques. The present work was undertaken to study the lectin binding properties of normal and RNA tumor virus-infected cells and their associated viruses using lectins and ferritin-conjugated lectins of five different specificities.

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