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  • 2010-2014
  • 2000-2004  (43)
  • 1975-1979  (515)
  • Life Sciences  (558)
  • 101
    Electronic Resource
    Electronic Resource
    The regional association of actin and myosin with sites of particle phagocytosis (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 369-384 
    Details
    ISSN: 0091-7419
    Keywords: phagocytosis ; actin ; myosin ; macrophages ; immunofluorescence ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Contractile proteins are thought to play a causative role in motile processes such as phagocytosis. In order to investigate their role in phagocytosis further, simultaneous immunofluorescence localization of F-actin and myosin was carried out in resident mouse peritoneal macrophages after phagocytosis of opsonized zymosan particles. Both actin and myosin appeared to concentrate rapidly at sites of particle phagocytosis. The observed concentration of both proteins at such sites preceded ultimate particle engulfment. Cytochalasin B, a drug which was shown to block pseudopod extensions around the particle, did not prevent the concentration of the two contractile proteins at cell-particle binding sites. This result ruled out path-length effects as an explanation for the observed concentration of actin and myosin at phagocytic sites. Kinetic analysis showed that actin rapidly concentrates at particle-cell binding sites within minutes (or less) of contact with cell surface. The two proteins are present throughout the engulfment phase until and after ingestion is complete. Finally, at later times the particles become clustered over the cell nucleus and the particle-associated actin-myosin seen earlier is no longer evident.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120308
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  • 102
    Electronic Resource
    Electronic Resource
    Rhodopsin phosphorylation suggests biochemical heterogeneities of retinal rod disks (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 419-424 
    Details
    ISSN: 0091-7419
    Keywords: frog retina ; rod membranes ; rhodopsin ; phosphorylation ; disk heterogeneity ; papainolysis ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Frogs (Rana pipiens) were injected subcutaneously with (3H)-leucine and allowed to incorporate the radioactive amino acid into newly assembled disks in the retinal rod outer segment. The labeled disks served as a temporal market for following the turnover of rod outer segments. Animals were killed at different times after injection and outer segments were isolated and phosphorylated with ATP in the light. The visual pigment (as isorhodopsin) was regenerated with 9-cis retinal, extracted, and chromatographed on epichlorohydrin triethanolamine cellulose so that phosphorylated pigment could be separated from unphosphorylated pigment. The ratio of (3H)-radioactivity of phosphorylated pigment to that of unphosphorylated pigment was then plotted against the time after injection. The ratio was high when (3H)-labeled disks were largely associated with the basal region of the rod and decreased as the labeled disks moved toward the rod apical region. The results were interpreted as suggesting that newer disks are phosphorylated preferentially to older disks. Papain digestion of (3H)-labeled disks indicated that rhodopsin in newer disks is more susceptible to proteolysis than that in older disks.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120402
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  • 103
    Electronic Resource
    Electronic Resource
    Isolation and characterization of human placental chorionic villar extracellular matrix (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 457-466 
    Details
    ISSN: 0091-7419
    Keywords: human placental basement membrane ; extracellular matrix ; human chorionic villar basement membrane ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The cell-free extracellular matrix of human placental chorionic villi has been prepared by a procedure employing extraction of the terminal villar fragments with the detergents Triton X-100 and sodium deoxycholate. The isolated human placental extracellular matrix retains an intact, but collapsed, histoarchitecture, as observed by scanning and transmission electron microscopy. It remains intact, in large part because of the presence of continuous sheets of villar basement membranes and associated interstitial collagen fibers and scattered patches of fibrin. The staining characteristics and chemical composition of the isolated human placental extracellular matrix are similar to those reported for basement membranes in several tissues and indicate the presence of collagen-like and glycoprotein components in this preparation. Gel electrophoresis of urea-SDS-mercaptoethanol extracts of the matrix showed that it consists of several polypeptide components of various molecular weights, some of which are associated into high molecular weight complexes by disulfide bonds.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120405
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  • 104
    Electronic Resource
    Electronic Resource
    Ribosome crystallization in homogenates and cell extracts of chick embryos (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 349-357 
    Details
    ISSN: 0091-7419
    Keywords: ribosomes ; crystallization ; hypothermia ; chick embryos ; reconstruction from electron micrographs ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Ribosome microcrystals have been obtained for the first time in homogenates and extracts of chick embryos mainly in the form of P422 stacks that have average linear dimensions some 40% greater than those obtained in vivo.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100306
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  • 105
    Electronic Resource
    Electronic Resource
    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100401
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  • 106
    Electronic Resource
    Electronic Resource
    Comparison of the major polypeptides of the erythrocyte nuclear envelope (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 405-418 
    Details
    ISSN: 0091-7419
    Keywords: nuclear envelope polypeptides ; chemical and enzymatic digestion ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The three most abundant nonhistone polypeptides (molecular weights 75,000, 71,000 and 61,000) of the avian erythrocyte nucleus have previously been isolated in the nuclear envelope fraction. They have been separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis and peptide-mapped after limited enzymatic digestion. Three enzymes-chymotrypsin, papain and Staphylococcus aureus protease-were used. Results obtained with each enzyme indicate strong similarities between the three nuclear envelope polypeptides. The amino acid compositions of the two most abundant polypeptides (P75 and P71) have been determined and found to be similar. Further, they readily yield large fragments upon brief alkaline hydrolysis. For both P75 and P71 the degree and the pattern of alkaline fragmentation are almost identical. A 61,000-dalton polypeptide which appears to be P61 is obtained from P75 and P71 by mild acid hydrolysis. These results establish the close chemical similarity of these predominant polypeptides in the erythrocyte nucleus and suggest that they serve related functions.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100404
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  • 107
    Electronic Resource
    Electronic Resource
    The errors in assembly of MuLV in interferon treated cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 35-46 
    Details
    ISSN: 0091-7419
    Keywords: MuLV ; uninfectious particles ; interferon ; virus assembly ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Interferon treatment of JLSV-6 cells chronically infected with Rauscher MuLV leads to the formation of noninfectious particles (interferon virions) containing the structural proteins of env and gag genes as well as additional viral polypeptides. In the control virions the major glycoprotein detected is gp71, interferon virions contain in addition to gp71 and 85k dalton (gp85) glucosamine-containing, fucose-deficient glycoprotein which is recognized by antiserum to MuLV but not by the gp71 antiserum. The surface iodination of the intact virions indicates that both gp71 and gp85 are the major components of the external virions envelope. However, unlike the control virions in which gp71 associates with p15E (gp90), the gp71-p15E complex was not detected in interferon virions. The analysis of the iodinated proteins of the disrupted interferon virions revealed the presence of 85k and 65k dalton polypeptides preciptable with antiserum against MuLV, which are not present in the control virions. The difference in the polypeptide pattern of virions produced in the presence of interferon does not seem to be a consequence of the slowdown in the synthesis of viral proteins or their processing in the interferon-treated cells. Both the structural proteins of env and gag genes seem to be synthesized and processed at a comparable rate in the interferon-treated and -untreated cells. These results indicate an alteration of virus assembly in the presence of interferon.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120105
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  • 108
    Electronic Resource
    Electronic Resource
    Role of the microfibrillar system in knob action of transformed cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 335-354 
    Details
    ISSN: 0091-7419
    Keywords: knobs or blebs ; transformed cells ; reverse transformation ; time-lapse cinematography ; scanning EM ; transmission EM ; microtubules and microfilaments or microfibrillar system ; colcemid ; cytochalasin B ; dibutyryl cyclic AMP ; indirect immunofluorescence ; antiactin ; antitubulin ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Transformed cells often display knobs (or blebs) distributed over their surface throughout most of interphase. Scanning electron microscopy (SEM) and time-lapse cinematography on CHO-K1 cells reveal roughly spherical knobs of 0.5-4 μm in diameter distributed densely around the cell periphery but sparsely over the central, nuclear hillock and oscillating in and out of the membrane with a period of 15-60 sec. Cyclic AMP derivatives cause the phenomenon of reverse transformation, in which the cell is converted to a fibroblastic morphology with disappearance of the knobs. A model was proposed attributing knob formation to the disorganization of the jointly operating microtubular and microfilamentous structure of the normal fibroblast. Evidence for this model includes the following: (1) Either colcemid or cytochalasin B (CB) prevents the knob disappearance normally produced by cAMP, and can elicit similar knobs from smooth-surfaced cells; (2) knob removal by cAMP is specific, with little effect on microvilli and lamellipodia; (3) immunofluorescence with antiactin sera reveals condensed, amorphous masses directly beneath the membrane of CB-treated cells instead of smooth, parallel fibrous patterns of reversetransformed cells or normal fibroblasts; (4) transmission electron microscopy (TEM) of sections show dense, elongated microfilament bundles and microtubules parallel to the long axis of the reverse-transformed CHO cell, but sparse, random microtubules throughout the transformed cell and an apparent disordered network of 6-nm microfilaments beneath the knobs; (5) cell membranes at the end of telophase, when the spindle disappears and cleavage is complete, display typical knob activity as expected by this picture.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120306
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  • 109
    Electronic Resource
    Electronic Resource
    Tumor-associated antigenic differences between the primary and the descendant metastatic tumor cell populations (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 385-402 
    Details
    ISSN: 0091-7419
    Keywords: hybrid resistance ; NK cells ; cytotoxic lymphocytes ; tumor-associated antigens ; primary and metastatic tumor cells ; immunoselection ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The existence of antigenic differences between cell populations in the local growth of the 3LL tumor (L-3LL) and its lung metastases (M-3LL) was studied. Normal C57BL/6 spleen cells sensitized in vitro for 5 days against L-3LL monolayers lysed preferentially L-3LL targets but not M-3LL tumor cell targets. Conversely, anti-M-3LL-sensitized lymphocytes killed M-3LL targets more efficiently than they killed L-3LL targets. Furthermore, spleen cells from mice bearing subcutaneous L-3LL tumors were significantly more cytotoxic to L-3LL targets than to M-3LL targets and vice versa. M-3LL cells were found also to be more resistant in vitro and in vivo to natural killer cells than were L-3LL tumor cells. M-3LL cells were more resistant than L-3LL cells to hybrid resistant mechanisms when they were inoculated into F1 (C3Heb X C57BL/6) or F1 (BALB/c X C57BL/6) mice. Anti-M-3LL lymphocytes generated both in vitro and in vivo, but not anti-L-3LL lymphocytes, admixed with L-3LL or M-3LL tumor cells and inoculated into footpads of syngeneic recipients suppressed the development of lung metastases. These results suggest that metastatic cells are indeed phenotypic variants of the local growing tumor cell populations. Presumably, these variants are selected for their capacity to home to and grow in the lungs, and for their resistance to specific immune effects initially evoked against the local tumor and to nonspecific natural killer cells. These data may prove to be of importance with respect to any rational approach to the problem of immunotherapy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120309
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  • 110
    Electronic Resource
    Electronic Resource
    Isolation and properties of gamma protein, the major transmembrane sialoglycoprotein of the HeLa cell (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 435-455 
    Details
    ISSN: 0091-7419
    Keywords: N-acetyl neuraminic acid ; neuraminidase (Vibrio cholerae) ; sialic acid ; wheat germ agglutinin receptor ; membrane glycoprotein ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The surface of the HeLa cell is composed of a heterogeneous population of sialogly coproteins which undergo lectin-mediated endocytosis (Kramer and Canellakis, Biochim Biophys Acta 551:328, 1979). One such sialoglyco-protein, gamma protein, is the major periodate-Schiff-reactive and [3H]-glucosamine-labeled component of the plasma membrane; it has an apparent molecular weight of 165,000. Gamma protein is also the major [125I]-wheat germ agglutinin-binding component in sodium dodecyl sulfate gels. Neuraminidase digestion of HeLa cells abolishes binding of [125I]-wheat germ agglutinin to gamma protein, and pretreatment of cells with wheat germ agglutinin protects gamma protein from desialation by neuraminidase. suggesting that wheat germ agglutinin binds to the sialic acid residues of gamma protein at the cell surface. Gamma protein can be extracted with various detergents but not with high-salt, chelating, or chaotropic agents. Intact inside-out plasma membrane vesicles have been prepared from HeLa cells that had phagocytosed latex particles. Treatment of these isolated vesicles with trypsin reduces the molecular weight of gamma protein. These results suggest that gamma protein is an integral membrane protein that spans the plasma membrane. Gamma protein can be purified to homogeneity by sequential lithium diiodosalicylate-phenol extraction, wheat germ agglutinin-agarose affinity chromatography, and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120404
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  • 111
    Electronic Resource
    Electronic Resource
    Alteration of human breast tumor cell membrane functions by chromosome-mediated gene transfer (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 355-367 
    Details
    ISSN: 0091-7419
    Keywords: Alkaline phosphatase ; chromosome-mediated gene transfer ; human breast tumor cells ; hydrocortisone ; lipochromes ; membrane bound enzymes ; nucleoside uptake ; thymidine kinase ; thymidine transport ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: BOT-2 cells (human breast tumor origin) have an impaired ability to utilize exogenous thymidine. Previous studies revealed this deficiency to be the permeation event rather than phosphorylation, since the cells have active thymidine kinase. Chromosome-mediated gene transfer was used to transfer genetic information in the form of metaphase chromosomes, from HeLa-65 cells to the BOT-2 cells, correcting the permease deficiency. Poly-L-ornithine or lipochromes were used for facilitation of chromosome uptake. After selection on HAT medium, transferant clones were isolated at a frequency of 4 X 10-5 and 1 X 10-5, respectively. Transferants MGP-1 and MGL-1 are stable after 18 months and have been characterized on the bases of purine and pyrimidine nucleoside uptake, relative thymidine kinase activities, alkaline phosphatase activities, and hydrocortisone-induced alkaline phosphatase activity. MGP-1 demonstrates positive thymidine uptake and incorporates radiolabeled thymidine into DNA. MGL-1 remains thymidine transport-deficient and survives on HAT by increasing endogenous dihydrofolate reductase activity. Alkaline phosphatase activity in MGL-1 is similar to HeLa-65, 2% of that in BOT-2, and in addition, is inducible 25-30-fold by 3 μM hydrocortisone. We have separated, genetically, a thymidine permease function from phosphorylation in cells of human origin and have transferred genetic information for the regulation of alkaline phosphatase.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120307
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  • 112
    Electronic Resource
    Electronic Resource
    Analysis of transmembrane proteins from eukaryotic cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 403-417 
    Details
    ISSN: 0091-7419
    Keywords: mouse L-929 cells ; “inside-out” configuration ; gel electrophoresis ; lectin-binding proteins ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The topography and properties of plasma membrane proteins from mouse L-929 cells are studied by comparing their availability for enzymatic labeling on the external and internal surfaces of the membrane. In order to study the internal surface, phagolysosomes are prepared from cells after they ingest latex particles. The plasma membrane surrounding these seems to have an “inside-out” orientation. The sugars of the membrane glycoproteins in intact phagolysosomes are not available for interaction with lectins or available for periodate-borotritide labeling. A comparison of the lectin-binding proteins lableled by lactoperoxidase-catalyzed iodination on the external cell surface with those labeled on the internal cell surface suggests that a variety of plasma membrane glycoproteins span the lipid bilayer.Using two-dimensional gel electrophoresis it has been shown that selected proteins are labeled at both the internal and external faces of the plasma membrane. Analysis of the 2-D gel electrophoregrams reveals that there are two distinct prominent proteins at 60,000 and 100,000 daltons which are enzymatically iodinated from both sides of the membrane. The partial hydrolysis of the 100,000 dalton protein reveals that different peptides are iodinated when the iodination is performed on intact cells or on the phagolysosomes. These proteins are extensively phosphorylated in cells incubated with inorganic 32P. We conclude that the phagolysosome is probably oriented in an “inside-out” configuration and that this membrane preparation can be used to study the topographic organization of membrane proteins.The use of oriented membranes, selective labeling of proteins, and affinity separation of proteins in combination with gel electrophoresis to define the position and properties of proteins is discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120310
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  • 113
    Electronic Resource
    Electronic Resource
    Mitogenic effects of murine serum and fibroblast growth factor on EGF nonproliferative variants of 3T3 (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 467-470 
    Details
    ISSN: 0091-7419
    Keywords: epidermal growth factor ; fibroblast growth factor ; cell division ; mitogenesis ; growth control ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The enhanced ability of murine serum to support growth of 3T3 cells, when compared with fetal calf serum, is also evident on variants of 3T3 cells lacking the ability to bind epidermal growth factor (EGF). Variant 3T3 cell lines unable to bind EGF also retain a mitogenic response to fibroblast growth factor.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120406
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  • 114
    Electronic Resource
    Electronic Resource
    Cross-linkings between spectrin and band 3 in human erythrocyte membranes (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 97-109 
    Details
    ISSN: 0091-7419
    Keywords: spectrin ; band 3 ; covalent cross-linking ; two-dimensional gel electrophoresis ; 125I-labeling ; chymotrypsin digestion ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A specific structural association between spectrin component 1 and band 3 in human erythrocyte membrane has been demonstrated by covalent cross-linkings, specific labeling, and the technique of two-dimensional gel electrophoresis. A complex of 330,000 daltons, representing 1 + 3, was produced in mildly oxidized membranes at physiologic pH and isotonic conditions but not at hypotonic conditions (〈 10 mM KCl or NaCl). The yield of this complex decreased dramatically as the monovalent cation concentration decreased from 90 mM to 30 mM. The presence of Mg++ or Ca++ (2 mM) at low ionic strength promoted 1 + 3 cross-linking in an amount similar to that produced at isotonic conditions. The specific segment of band 3 involved in the cross-linking was also investigated by means of chymotrypsin digestion of band 3 in the intact red cells. The results showed the cross-links between spectrin component 1 and the 55,000-dalton fragment of band 3 at physiologic pH and isotonic conditions. This is consistent with the idea that band 3 is anchored on or contacted with the submembrane meshwork at the cytoplasmic membrane surface.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100109
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  • 115
    Electronic Resource
    Electronic Resource
    Structure, function, and antigenicity of cholera toxin (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 137-149 
    Details
    ISSN: 0091-7419
    Keywords: cholera toxin ; chemical modification ; amino acid composition ; antigenic relationships ; radioimmunoassay ; adenylate cyclase ; ovine luteinizing hormone ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Chemical modification of intact cholera toxin or its B subunit by either partial nitration or reduction and alkylation did not result in significant loss of biological activity as determined by measurement of cyclic AMP in Chinese hamster overy cells. Complete nitration or succinylation in the presence of guanidine hydrochloride resulted in complete loss of biological activity and significantly affected the immunoreactivity of the toxin and B subunit. Compositional analyses of both the isolated α and γ chains of the toxin were typical of globular proteins and did not reveal significant hydrophobicity. Analysis of antigenic relationships by radioimmunoassay indicated a partial crossreactivity between the α chain and the B subunit of cholera toxin. Since previous structural studies of the β chain of cholera toxin indicated chemical similarity with the glycoprotein hormones [Kurosky et al. Science 195:299 (1977)], radioimmunoassay procedures were employed to investigate for possible crossreactivity. No evidence of crossreactivity between cholera toxin subunits and subunits of ovine luteinizing hormone was found.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100204
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  • 116
    Electronic Resource
    Electronic Resource
    Interaction between glycophorin and phospholipids in recombined systems (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 241-251 
    Details
    ISSN: 0091-7419
    Keywords: boundary lipid ; 31PNMR ; spin labels ; glycophorin ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Both the MN-glycoprotein from human erythrocytes and the hydrophobic fragment from the protein isolated with trypsin treatment, T(is), have been recombined with egg phosphatidylcholine in bilayers at various phospholipid/protein ratios. In order to investigate the effect of the protein on the phospholipid headgroups, 31P nuclear magnetic resonance spectra were obtained with the MN-glycoprotein recombined with egg phosphtidylcholine, which revealed two classes of phospholipid enviroments, one immobilized and one not immobilized. Electron spin resonance (ESR) of fatty acid methyl ester spin labels provided supporting evidence.Computer analysis of the ESR spectra indicate that 4-5 moles of phospholipid are immobilized per mole of protein over a wide range of lipid-to-protein ratios. The immobilization of the phospholipids appears mediated by both the polar headgroups and the hydrocarbon tails of the phospholipid.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100213
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  • 117
    Electronic Resource
    Electronic Resource
    Stimulation of human vascular endothelial cell growth by a platelet-derived growth factor and thrombin (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 361-370 
    Details
    ISSN: 0091-7419
    Keywords: endothelial cells ; platelet-derived growth factor ; thrombin ; wound healing ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Repair of a vascular wound is mediated by migration and subsequent replication of the endothelial cells that form the inner lining of blood vessels. We have measured the growth response of human umbilical vein endothelial cells (HuE) to two polypeptides that are transiently produced in high concentrations at the site of a wound; the platelet-derived growth factor (PDGF) and the protease thrombin. When 104 HuE cells are seeded as a dense island (2-mm diameter) in the center of a 16-mm tissue culture well in medium containing 20% human serum derived from platelet-poor plasma (PDS), no increase in cell number or colony size is observed. With the addition of 0.5 ng/ml partially purified PDGF, colony size increases and the number of cells after 8 days is 4.8 × 104. When human thrombin (1 μg/ml) is added along with the PDGF, the cell number rises to 9.2 × 104. Thrombin alone stimulates no increase in cell number. Although partially purified PDGF stimulates endothelial cells maintained in PDS as well as those maintained in whole blood serum (WBS), pure PDGF is active only when assayed in medium that contains WBS and is supplemented with thrombin. These results suggest the existence of a second class of platelet-derived factors that enable HuE cells to respond to the mitogenic activity of the purified platelet mitogen and thrombin.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110311
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  • 118
    Electronic Resource
    Electronic Resource
    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110101
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  • 119
    Electronic Resource
    Electronic Resource
    Preliminary molecular replacement results for a crystalline gene 5 protein-deoxyoligonucleotide complex (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 479-489 
    Details
    ISSN: 0091-7419
    Keywords: protein-nucleic acid interactions ; X-ray diffraction ; gene 5 protein ; molecular replacement ; DNA ; fd bacteriophage ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Complexes of the gene 5 protein from bacteriophage fd with a variety of oligodeoxynucleotides, ranging in length from two to eight and comprised of several different sequences, have been formed and crystallized for X-ray diffraction analysis. The crystallographic parameters of four different unit cells, all of which are based on hexagonal packing arrangements, indicate that the fundamental unit of the complex is composed of six gene 5 protein dimers. We believe this aggregate has 622 point group symmetry and is a ring formed by end-to-end closure of a linear array of six dimers. From our results we have proposed a double-helix model for the gene 5 protein-DNA complex in which the protein forms a spindle or core around which the DNA is spooled. Currently 5.0-Å X-ray diffraction data from one of the crystalline complexes is being analyzed by molecular replacement techniques to obtain a direct image of the protein-nucleic acid complex.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100410
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    Detection of erythrocyte membrane structural abnormalities in lecithin: Cholesterol acyltransferase deficiency using a spin label approach (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 1-7 
    Details
    ISSN: 0091-7419
    Keywords: erythrocyte membranes ; LCAT deficiency ; electron spin resonance ; spin label ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The membrane fluidity of erythrocytes from patients with Lecithin: cholesterol acyltransferase (LCT) deficiency was studied by means of electron spin resonance. The temperature dependence of the separation of the outer extrema of the spectra of 2-(3-carboxy-propyl)-4,4-dimethyl, 2-tridecyl-3-oxazolidinyloxyl spin probe was monitored for normal, presumed carrier and clinically affected subjects. The temperature profile of controls was significantly different form that of the presumed carriers and the clinically affected individuals. The results show that the compositional abnormalities previously noted in erythrocyte membranes from patients with LCAT deficiency are associated with alterations in the physicochemical state of the membrane. An investigation of the spectral lineshapes below 10°C allowed a distinction to be made at the membarne level between clinically affected subjects and clinically normal heterozygous carriers. Alterations in the temperature dependence of electron spin resonance parameters may provide a sensitive index of red cell membrane alterations in pathological states of generalized membrane involvement.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110102
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    Flow cytometry analysis of early DNA content changes in human and monkey cells following infection with simian virus 40 (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 25-31 
    Details
    ISSN: 0091-7419
    Keywords: simian virus 40 ; flow cytometry ; DNA synthesis induction ; transformation ; human diploid cells ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Simian virus 40 (SV40) is capable of inducing cellular DNA synthesis in permissive and nonpermissive cells. Utilizing flow cytometry, we analyzed the DNA content changes in two diploid human cell strains and two monkey cell lines. The osteogenesis imperfects (OI) human skin fibroblasts were induced into DNA synthesis, and within one to two cell generations, a polyploid cell population was produced. With WI-38 phase II cells, a similar pattern of increased cycling of cells into DNA synthesis was observed; however, the majority (∼60%) of the cells were blocked in the G2 + M phase of the cell cycle. At later time intervals, an increase in the G1 population was demonstrated. The two monkey cell lines responded to SV40 virus with an accumulation of cells in the G2 + M phase of the cell cycle. Thus, two diploid human cell strains exhibited different cell cycle kinetics early after infection with SV40 virus. The one strain (WI-38) behaved similarly to the two monkey cell lines studied. The other strain (OI) responded similarly to nonpermissive (transformin) cells infected with SV40 virus.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110104
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    Endogenous cyclic AMP does not modulate transport of hexoses, nucleosides, or nucleobases in chinese hamster ovary cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 51-60 
    Details
    ISSN: 0091-7419
    Keywords: cyclic AMP ; transport of nucleosides ; nucleobases ; hexoses ; Chinese hamster ovary cells ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In a previous study we have demonstrated that neither extracellular nor intracellular cyclic adenosine monophosphate (AMP) levels directly affect the uptake of nucleosides, nucleobases, or hexoses by various types of cultured mammalian cells. Uptake of these nutrients into cells, however, involves two processes operating in tandem: facilitated transport across the membrane and intracellular phosphorylation; and uptake rates generally reflect the rates of substrate phosphorylation rather than of transport. In the present study we have examined the question of whether substrate transport per se is regulated by intracellular cyclic AMP. Initially various cell lines, grown both in suspension and monolayer culture, were screened for their cyclic AMP response to prostaglandin E1, isoproterenol, and inhibitors of cyclic AMP phosphodiesterase. Prostaglandin E1 treatment of Chinese hamster ovary cells was selected as the systems giving the largest and most consistent (50-fold to 100-fold) elevation of cyclic AMP. Rapid kinetic techniques were used to measure the transport of 3-O-methylglucose, thymidine, adenosine, hypoxanthine, and adenine in wild-type cells and in mutant sublines incapable of phosphorylating these substrates. In no case was an increse in intracellular cyclic AMP accompanied by a singinficant change in the rate of transport of these substrates, although prostaglandin E1 slightly inhibited the transport of various substrates.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110106
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    Extracellular lectin and its glycosaminoglycan inhibitor in chick muscle cultures (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 61-67 
    Details
    ISSN: 0091-7419
    Keywords: lectin ; glycosaminoglycan ; extracellular material ; cell matrix ; cellular interactions ; myoblast development ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Embryonic chick muscle contains two developmentally regulated lectins, which may be involved in cell interactions. These endogenous lectins are assayed as agglutinins of appropriate test erythrocytes. One of these, called lectin-2, interacts with specific glycosaminoglycans, especially heparin and dermatan sulfate. Lectin-2 is present at constant levels in both chick fibroblast and chick muscle cells throughout 14 days of culture but is released into the medium of cultured embryonic muscle after 7-8 days of culture, soon after myoblast fusion. Lectin-2 interacts strongly with a component of substrate-attached material in embryonic muscle cultures which is extractable from the culture dishes with alkali after the cells have been removed with ethylediaminetetraacetic acid. The active component in the substrate-attached material appears to be a glycosaminoglycan that is a more potent inhibitor of lectin-2 agglutination activity than any of the known glycosaminoglycans that we have tested. The active material is degraded by chondroitinase ABC but not by chondrotinase AC, hyaluronidase, or proteolytic enzymes and thus appears to be similar to dermatan sulfate. The results of these studies raise the possibility that lectin-2 functions by interacting with glycosaminoglycans, either associated with the cell surface or with the extracellular matrix.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110107
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    Synergistic stimulation of early events and DNA synthesis by phorbol esters, polypeptide growth factors, and retinoids in cultured fibroblasts (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 79-93 
    Details
    ISSN: 0091-7419
    Keywords: Phorbol esters ; retinoids ; vasopressin ; mitogens ; uridine uptake ; deoxyglucose uptake ; ion fluxes ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: 12-O-Tetradecanoyl-phorbol-13-acetate (TPA), in the absence of serum, acts synergistically with a range of polypeptide growth factors to stimulate DNA synthesis in quiescent Swiss 3T3 cells. These growth factors include epidermal growth factor (EGF), insulin, and the peptide produced by BHK cells transformed by SV-40 virus (fibroblast-derived growth factor, FDGF). Retinoids also show mitogenic synergism with TPA or polypeptide growth factors. The spectrum of mitogenic synergisms displayed by TPA are similar to those of vasopressin, a pituitary peptide. However, TPA and vasopressin do not synergistically interact to stimulate DNA synthesis in quiescent 3T3 cells. This suggests that TPA and vasopressin act via an identical biochemical pathway. Several lines of evidence suggest rapid postreceptor convergence of the mitogenic mechanisms of action of the hormone and the tumor promotor. Thus, vasopressin and TPA both inhibit EGF binding to cellular receptors. Furthermore, TPA and vasopressin induce a similar array of early events in quiescent cells - most strikingly, identical stimulation of Rb+ influx. Stimulation of ion flux is suggested as the possible convergence point of the pathway by which TPA and vasopressin act as mitogens.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110109
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    Tumor metastases and cell-mediated immunity in a model system in DBA/2 mice. VIII. Expression and shedding of Fcγ receptors on metastatic tumor cell variants (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 105-115 
    Details
    ISSN: 0091-7419
    Keywords: tumor metastases ; Fc receptor ; shedding ; tumor variants ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The expression of receptors for the Fc portion of IgG immunoglobin molecules was studied on tumor cell lines with high and low metastatic capacity. Two tumor cell lines from DBA/2 mice that had high metastatic activity, ESb and MDAY-D2, contained a high percentage of Fc receptor positive cells, as detected in a rosette assay with IgG antibody-coated erythrocytes (EA). In contrast, the low metastatic parental line Eb, from which ESb was derived, contained only a low percentage of EA-rosette-forming cells. ESb ascites tumor cells adapted to tissue culture in the presence of 2-mercaptoethanol (2ME) had a high expression of Fc receptors, whereas a cell line adapted to tissue culture in the absence of 2ME had a low expression of Fc receptors.“Soluble” Fc receptors were detectable by their ability to bind to EA and to cause blocking of rosette formation. They were found to be present in fluids from tumor-bearing animals, such as serum and cell-free ascites. Even animals with an ascites tumor of the low-metastatic line Eb contained “soluble” Fc receptors.The results are discussed with regard to their possible significance for tumor metastasis.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110111
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    Cholesterol levels and plasma membrane fluidity in 3T3 and SV101-3T3 cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 477-483 
    Details
    ISSN: 0091-7419
    Keywords: virus transformation ; membrane fluidity ; plasma membrane ; filipin ; cholesterol ; spin label ; lectin agglutination ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Polyene antibiotics such as filipin selectively inhibit wheat germ agglutinin-induced agglutination of transformed and malignant cells compared to normal cells (Hatten ME, Burger MM: Biochemistry 18:739, 1979). Since filipin binds specifically to cholesterol, we measured cholesterol levels in 3T3 cells and SV101-3T3 cells. SV101-3T3 cells contained 50-100% more cholesterol per cell than 3T3 cells. Both cell types were starved for cholesterol by growth in lipid-depleted medium plus 25-hydroxycholesterol. The cholesterol level of SV101-3T3 cells decreased by 30-50%, while the level in 3T3 cells remained constant. Filipin-stained SV101-3T3 cells revealed bright patches of filipin under fluorescence microscopy. These patches were absent in 3T3 cells and in SV101-3T3 and 3T3 cells starved for cholesterol. We selectively labeled plasma membranes of these cells with a spin label analog of phosphatidylcholine. The spin label indicated differences in plasma membrane fluidity that may be related to the different cholesterol levels in 3T3 and SV101-3T3 cells.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110406
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    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120101
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    Glycosaminoglycans of the plasma membranes of renal tubule and liver cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 15-22 
    Details
    ISSN: 0091-7419
    Keywords: glycosaminoglycans ; glycocalyx ; liver and kidney plasma membranes ; hyaluronic acid ; chondroitin sulfates ; heparin sulfates ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Glycosaminoglycans were isolated from plasma membranes of hepatic and renal tubule cells of guinea pig. Plasmalemma of renal tubule cells contained more total glycosaminoglycans, hyaluronic acid, chondroitin-4 sulfates and chondroitin-6 sulfates, and less dermatan sulfates and heparin sulfates than liver plasma membranes. These glycocalyx components, owing to their polyanionic properties, may have a role in the transport of water, ions, and macromolecules across the cell membrane.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120103
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    Effects of the tumor promoter TPA on the induction of DNA synthesis in normal and RSV-transformed rat fibroblasts (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 63-72 
    Details
    ISSN: 0091-7419
    Keywords: tumor promoter ; DNA synthesis ; transformed cells ; serum stimulation ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Induction of DNA synthesis by the tumor promoter tetradecanoyl phorbol acetate (TPA) was studied in a line of cultured rat fibroblasts (Rat-1) and their ffRous sarcoma virus-transformed derivative (Rat-1(RSV)). Following serum deprivation for 54 h to achieve quiescene, semiconservative DNA replication was measured by incubation of cells in BrdUrd and FdUrd after serum stimulation in the presence or absence of TPA. Optimal concentrations of TPA (0.1-0.5 μg/ ml) in serum-free medium induced a small increase (10-15%) in the amount of DNA made over a 30-h period in both Rat-1 and Rat-1 (RSV) cells. When Rat-1 cells were stimulated by a 4-h serum pulse, 30% of the DNA was replicated by 30 h. If the serum pulse was follwed by TPA addition, 702% DNA replication wass observed. If the serum pulse was preceded by TPA addition, the onset of DNA synthesis waas delayed by several hous, but stimulation of DNA synthesis occurred. In contrast, the Rat-1 (RSV) cells did not show an increase in DNA synthesis induced by TPA in similar protocols, but the serum-induced onset on DNA synthesis was delayed by several hours in the presence of TPA. Therefore, TPA acts as a co-inducer of DNA synthesis in the Rat-1 but not in the Rat-(RSV) cells. The parent alcohol, phorbol, was inactive in Rat-1 cells, but delayed the onset of DNA synthesis in the Rat(RSV) cells. We conclude that the co-inducing and delaying activities of TPA on DNA synthesis appear to be distinct and to act at different points in the G1 phase of the cell cycle.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120107
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    Membrane dynamics of differentiating cultured embryonic chick skeletal muscle cells by fluorescence microscopy techniques (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 47-61 
    Details
    ISSN: 0091-7419
    Keywords: plasma membrane ; fluidity ; skeletal muscle ; myogenesis laser ; fluorescence photobleaching recovery ; fluorescence depolarization ; carbocyanine ; perylene ; fluorescence anisotropy ; microviscosity ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Changes in membrane fluidity during myogenesis have been studied by fluorescence microscopy of individual cells growing in monolayer cultures of embryonic chick skeletal muscle cells. Membrane fluidity was determined by the techniques of fluorescence photobleaching recovery (FDR), with the use of a lipidsoluble carbocyanine dye, and by fluorescence depolarization (FD), with perylene used as the lipid probe. The fluidity of myoblast plasma membranes, as determined from FPR measurements in membrane areas above nuclei, increased during the period of myoblast fusion and then returned to its initial level. The membrane fluidity of fibroblasts, also found in these primary cultures, remained constant. The fluidity in specific regions along the length of the myoblast membrane was studied by FD, and it was observed that the extended arms of the myoblast have the highest fluidity on the cell and that the tips at the ends of the arms had the lowest fluidity. However, since the perylene probe used in the FD experiments appeared to label cytoplasmic components, changes in fluidity measured with this probe reflect changes in membrane fluidity as well as in cytoplasmic fluidity. The relative change in each of these compartments cannot yet be ascertained. Tips have specialized surface structures, filopodia and lamellipodia, which may be accompanied by a more immobile membrane as well as a more rigid cytoplasm. Rounded cells, which may also have a more convoluted surface structure, show a lower apparent membrane fluidity than extended cells.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120106
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    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120201
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    Structural comparisons of the aggregates of tobacco mosaic virus protein (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 177-183 
    Details
    ISSN: 0091-7419
    Keywords: tobacco mosaic virus protein ; X-ray diffraction ; protein structure ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The coat protein of tobacco mosaic virus forms numerous aggregates, including the small A-protein, the disk, and two helical forms. The structures of the disk, the helical protein forms, and the virus are compared. Most of the differences are in the conformation of the chain between residues 89 and 113, which lies in the region of protein at the center of the virus, inside the RNA. It is disordered in the disk, but has a fixed conformation in the virus and the protein helices. The differences between the virus and the two helical protein forms are largely in the conformations of arginines and carboxylic acids in this region.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120204
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    Action of phorbol esters in cell culture: Mimicry of transformation, altered differentiation, and effects on cell membranes (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 195-208 
    Details
    ISSN: 0091-7419
    Keywords: tumor promoters ; phorbol esters ; plasminogen activator ; epidermal growth factor ; carcinogenesis ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The carcinogenic process is usually multifactor in its causation and multistep in its evolution. It is likely that entirely different molecular mechanisms underlie the many steps in this process. In contrast t o initiating carcinogens, the action of the tumor-promoting phorbol esters does not appear t o involve covalent binding t o cellular DNA and they are not mutagenic. Recent studies in cell culture have revealed two interesting biologic effects of the phorbol esters and related macrocyclic plant diterpenes. The first is that at nanomolar concentrations they induce several changes that resemble those seen in cells transformed by chemical carcinogens or tumor viruses. These include altered morphology and increased saturation density, altered cell surface fucose-glycopeptides, decrease in the LETS protein, increased transport of deoxyglucose, and increased levels of plasminogen activator and ornithine decarboxylase. In transformed cells exposed to phorbol esters the expression of these features is further accentuated. Phorbol esters do not induce normal cells to grow in agar but they do enhance the growth in agar of certain transformed cells. The second effect of the phorbol esters is inhibition of terminal differentiation. This effect extends to a variety of programs of differentiation and is reversible when the agent is removed. With certain cell culture systems induction of differentiation, rather than inhibition, is observed. Both the transformation mimetic and the differentiation effects are exerted by plant diterpenes that have tumor-promoting activity but not by congeners that lack such activity. The primary target of phorbol esters appears to be the cell membrane. Early membrane-related effects include enhanced uptake of 2-deoxyglucose and other nutrients, altered cell adhesion, induction of arachidonic acid release and prostaglandin synthesis, inhibition of the binding of epidermal growth factor t o cell surface receptors, altered lipid metabolism, and modifications in the activities of other cell surface receptors. A model of “two stage” carcinogenesis encompassing the known molecular and cellular effects of initiating carcinogens and tumor promoters is presented. According to this model, initiating carcinogens induce stable alterations in the cellular genome but these are not manifested until tumor promoters modulate programs of gene expression and induce the clonal outgrowth of the initiated cell.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120206
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    Direct linkage of thrombin to its cell surface receptors in different cell types (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 245-257 
    Details
    ISSN: 0091-7419
    Keywords: thrombin receptors ; epidermal growth factor receptors ; cell proliferation ; normal and transformed cells ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: When 125I-thrombin was incubated with foreskin fibroblasts, cervical carcinoma cells or fibrosarcoma cells of human origin, or with secondary chick embryo cells or Chinese hamster lung cells, it became directly linked to its cell surface receptors. The thrombin-receptor complex (TH-R) was derived exclusively from a pool of 125I-thrombin that had become specifically bound to the cell surface. The linkage was probably covalent, since the complex was resistant to boiling in sodium dodecyl sulfate and 2-mercaptoethanol. Raising the pH to 12 disrupted TH-R, but did not affect a similar complex between epidermal growth factor and its receptor, suggesting that the linkage of these mitogens to their receptors was different. Mild trypsin treatment removed the ability of cells to form TH-R; however, after a 24-h incubation in serum-free medium, trypsin-treated cells recovered the capacity to form TH-R, suggesting that TH-R resulted from interaction of 125I-thrombin with a cellular rather than a serum component. The mitogenic response of cells to thrombin was inversely related to the fraction of specifically bound 125I-thrombin represented by TH-R. The role of TH-R in mitogenesis may be clarified in future studies by obtaining clones of Chinese hamster lung cells that vary in their capacities to form TH-R and to respond to the mitogenic action of thrombin.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120209
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    Protein-RNA interactions during TMV assembly (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 305-320 
    Details
    ISSN: 0091-7419
    Keywords: tobacco mosaic virus ; structure ; RNA-binding site ; assembly ; protein-nucleic acid interactions ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A review of the structural studies of tobacco mosaic virus (TMV) is given. TMV is essentially a flat helical microcrystal with 16 1/3 subunits per turn. A single strand of RNA runs along the helix and is deeply embedded in the protein. The virus particles form oriented gels from which high-resolution X-ray fiber diffraction data can be obtained. This may be interpreted by the use of six heavy-atom derivatives to give an electron density map at 0.4 nm resolution from which the RNA configuration and the form of the inner part of the protein subunit may be determined. In addition, the protein subunits form a stable 17-fold two-layered disk which is involved in virus assembly and which crystallizes. By the use of noncrystallographic symmetry and a single heavy-atom derivative, it has been possible to solve the structure of the double disk to 0.28 nm resolution. In this structure one sees that an important structural role is played by four alpha-helices, one of which (the LR helix) appears to form the main binding site for the RNA. The main components of the binding site appear to be hydrophobic interactions with the bases, hydrogen bonds between aspartate groups and the sugars, and arginine salt bridges to the phosphate groups. The binding site is between two turns of the virus helix or between the turns of the double disk. In the disk, the region proximal to the RNA binding site is in a random coil until the RNA binds, whereupon the 24 residues involved build a well-defined structure, thereby encapsulating the RNA.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120304
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    Reconstituted low density lipoprotein: A vehicle for the delivery of hydrophobic fluorescent probes to cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 467-478 
    Details
    ISSN: 0091-7419
    Keywords: low density lipoprotein ; cell surface receptors ; receptor-mediated endocytosis ; reconstitution of lipoproteins ; fluorescent probes ; fluorescence-activated cell sorter ; familial hypercholesterolemia ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Previous studies have shown that the cholesteryl ester core of plasma low density lipoprotein (LDL) can be extracted with heptane and replaced with a variety of hydrophobic molecules. In the present report we use this reconstitution technique to incorporate two fluorescent probes, 3-pyrenemethyl-23, 24-dinor-5-cholen-22-oate-3β-yl oleate (PMCA oleate) and dioleyl fluorescein, into heptane-extracted LDL. Both fluorescent lipoprotein preparations were shown to be useful probes for visualizing the receptor-mediated endocytosis of LDL in cultured human fibroblasts. When normal fibroblasts were incubated at 37°C with either of the fluorescent LDL preparations, fluorescent granules accumulated in the perinuclear region of the cell. In contrast, fibroblasts from patients with the homozygous form of familial hypercholesterolemia (FH) that lack functional LDL receptors did not accumulate visible fluorescent granules when incubated with the fluorescent reconstituted LDL. A fluorescence-activated cell sorter was used to quantify the fluorescence intensity of individual cells that had been incubated with LDL reconstituted with dioleyl fluorescein. With this technique a population of normal fibroblasts could be distinguished from a population of FH fibroblasts. The current studies demonstrate the feasibility of using fluorescent reconstituted LDL in conjunction with the cell sorter to isolate mutant cells lacking functional LDL receptors.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100409
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    Analysis of cell surface interactions by measurements of lateral mobility (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 481-489 
    Details
    ISSN: 0091-7419
    Keywords: fluorescence photobleaching ; cell surface ; cytoskeleton ; lateral mobility ; membrane interactions ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Interactions of cell surface components with one another and with structures inside and outside the cell may have important physiological functions in the transmission of signals and the assembly of specialized structures. These interactions may be detected and analyzed through their effects on the lateral mobility of cell surface molecules. Measurements by a fluorescence photobleaching method have shown that in general lipid-like molecules diffuse rapidly and freely through the plasma membrane, whereas proteins move much more slowly or appear to be immobile. This dichotomy has been supposed to result from forces beyond the viscosity of the lipid bilayer, which specifically retard the diffusion of membrane proteins. This general picture should be qualified, however, by noting that the lateral mobility of lipid-like molecules can be influenced in detail by changes in the state of the plasma membrane such as result from mitosis or fertilization. The interactions of cell surface proteins that limit their lateral mobility are unknown. The effects of binding concanavalin A to localized regions of cell surface show that these interactions can vary in subtle and complex ways. It may soon be useful to interpret mobility experiments in terms of simple reaction models that attempt to describe surface interactions in physicochemical terms. More experimental data are needed to carry out this program and to relate interactions that affect mobility to the structural connections between cell surface components and the cytoskeleton, which have been detected by biochemical methods and electron and immunofluorescence microscopy.
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    URL: http://dx.doi.org/10.1002/jss.400120408
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    Covalent and non-covalent modulation of protein function (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 1-30 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120502
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  • 139
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    Extrachromosomal DNA (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 121-160 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120505
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  • 140
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    Growth control of normal and transformed cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 529-538 
    Details
    ISSN: 0091-7419
    Keywords: 3T3 cells ; transformed cells ; restriction point ; labile proteins ; growth factors ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Both serum factors and protein synthesis are required for normal cell growth. Swiss 3T3 cells require the serum growth factors insulin and EGF (epidermal growth factor) during the initial part of the G1 period, until they pass a restriction point about 2 h before the initiation of DNA synthesis. Concentration of cycloheximide that inhibit protein synthesis by as much as 70% dramatically lengthen the cell cycle before the restriction point, while the cell cycle after the restriction point remains nearly constant. These results are consistent with a model in which labile proteins are required for transit of cells past the serum-sensitive restriction point. The relation of these findings to the growth control of transformed cells is discussed.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110411
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    Alteration of insulin binding and cytoskeletal organization in cultured fibroblasts by tertiary amine local anesthetics (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 547-561 
    Details
    ISSN: 0091-7419
    Keywords: insulin receptors ; 125I-insulin binding ; microtubules and microfilaments ; cultured fibroblasts ; local anesthetics ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Tertiary amine local anesthetics cause a time- and dose-dependent, reversible increase in insulin binding sites in cultured chick embryo fibroblasts. Incubation of fibroblasts with 0.2 mM dibucaine for 3 h at 37°C results in a twofold to threefold increase in insulin binding, with an increase in average number of binding sites (Ka = 3.0 × 107M-1) from 9 × 103 to 29 × 103 per cell. Trypsin or ethylenegly coltetraacetic acid (EGTA) alone increases insulin binding twofold to threefold, but fails to further increase 125I-insulin binding in cells pretreated with dibucaine. Transformation of chick embryo fibroblasts with Rous sarcoma virus causes a threefold to fivefold increase in insulin binding, which is not further increased by incubation with dibucaine. As demonstrated by transmission electron microscopy, dibucaine and trypsin also induce changes in the cytoskeleton of chick embryo fibroblasts, characterized by disorganization and disappearance of microfilament and microtubule bundles. These alterations are accompanied by gross morphologic changes, including rounding of cells and appearance of numerous ruffles and blebs on the cell surface. These observations are consistent with the hypothesis that expression of surface receptors in cultured chick embryo fibroblasts is related to the organization and disorganization of cytoskeletal structures.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110413
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  • 142
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    Effect of thiourea and substituted thioureas on dynein ATPase and on the turbidity response of tetrahymena cilia (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 23-34 
    Details
    ISSN: 0091-7419
    Keywords: thiourea ; cilia ; dyneins ; ATPase ; sulfhydryl groups ; turbidity response ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The effects of thioura and of several substituted thioureas-phenylthiourea, α-naphtylthiourea, metiamide, and burimamide-on dynein ATPase have been studied. The substituted thioureas are over 30 times more potent than thiourea in causing enhancement of 30S dynein ATPase activity and inhibition of 14S dynein ATPase activity. The effects of thiourea and phenylthiourea can be prevented by very low concentrations of β-mercaptoethanol or dithiotheritol. Axonemal ATPase is also enhanced by the thioureas, but the reaction proceeds more slowly than for solubilized 30S dynein. Enhancement of 30S dynein ATPase by metiamide is prevented by low (∼ 1 μM) concentrations of ATP and, less effectively, by AMP-PNP, but not by AMP-PCP even though the latter is a stronger inhibitor of 30S dynein ATPase than is AMP-PNP.The thioureas inhibit the ATP-induced decrease in turbidity (measured as ΔA350) of axonemal suspensions. Inhibition of the turbidity response is also prevented by low concentrations of β-mercaptoethanol, but, in contrast to the irreversible enhancement of ATPase activity, inhibition of the turbidity response is largely reversible. The ability of 30S dynein to rebind onto twice extracted axonemes is not changed by treatment with phenylthiourea or metiamide.These observations indicate that the thioureas react with at least two sets of SH or S-S groups on axonemes. Reaction with the group(s) on the 30S dynein causes an apparently irreversible enhancement of ATPase activity. Reaction with another group(s) causes a reversible inhibition of the turbidity response.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120104
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    Ehrlich ascites tumor cell surface labeling and kinetics of glycocalyx release (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 115-125 
    Details
    ISSN: 0091-7419
    Keywords: glycocalyx ; cell surface ; tumor cells ; Ehrlich ascites tumor ; surface labeling ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Ehrlich ascites tumor cells spontaneously release cell surface material (glycocalyx) into isotonic saline medium. Exposure of these cells to tritium-labeled 4,4′-diisothiocyano-1,2′-dihenylethane-2,2′-disulfonic acid (3H2DIDS) at 4°C leads to preferential labeling of the cell surface coat. We have combined studies of the kinetics of 3H2DIDS-label release, the effects of enzymatic treatment, and cell electrophoretic mobility to characterize the 3H2DIDS-labeled components of the cell surface. Approximately 73% of the cell-associated radioactivity is spontaneously released from the cells after 5 h at 23°C. The kinetics of release is consistent with the first-order loss of two fractions; a slow (τ½ = 360 min) component representing 33% of the radioactivity, and a fast (τ½ = 20 min) component representing 26%. The remaining 14% of the labile binding may reflect mechanically induced surface release. Trypsin (1 μ/ml) also removes approximately 73% of the labeled material within 30 min and converts the kinectics of release to that of a single component (τ½ = 5.5 min). The specific activity (SA) of material released by trypsin immediately after labeling is 83% of the SA of the material spontaneously los in 1 h. However, trypsinization following a 2-h period of spontaneous release yields material of reduced (43%) SA. Neither 3H2DIDS labeling nor the initial spontaneous loss of labeled material alters cell electrophoretic mobility. However, extended spontaneous release is accompanied by a significant decrease in surface charge density. Trypsinization immediately following labeling or after spontaneous release (2 h) reduces mobility by 32%. We have tentatively identified the slowly released compartment as contributing to cell surface negativity.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120109
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  • 144
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    Polyoma T (tumor) antigen species in abortively and stably transformed cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 127-137 
    Details
    ISSN: 0091-7419
    Keywords: polyoma virus ; middle ; and small tumor antigens ; ts-a ; hr-t ; abortive transformation ; transformed cells ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Stable neoplastic transformation of cells by polyoma virus requires the participation of two viral genes, designated ts-a and hr-t. The effects of mutations in these two genes on the patterns of T-antigen synthesis during productive infection have been previously described: ts- a mutants are affected in the “large” (100K) nuclear T antigen, and hr-t mutants are affected in the “middle” (36K, 56K, 63K) and “small” (22K) T agtigens. The latter are associated predominantly with the plasma membrane (56K) and cytosol fractions, rrespectively.Here we examine the expression of the various forms of polyoma T antigen in nonproductive infection (abortive transformation) as well as in stably transformed cell lines of different species. The results on abortive transformation are essentially the same as those described above for productive infection. In stably transformed cells, the middle and small T antigens are seen to various extents. The large T antigen, however, is often absent or present below the level of detection. Clones lacking the large T antigen are found most often among mouse transformants, but are also seen among rat transformants. Retention of the 100K species in transformed cells therefore appears to be, at least in part, an inverse function of the level of permissivity of the host toward productive viral infection. These findings indicate that the induction of the transformed phenotype in both abortively and stably transformed cells generally does not require the large T antigen, but rather the products of the hr-t gene.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120110
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  • 145
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    7-Acetylcytochalasin B: Differential effects on sugar transport and cell motility (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 185-194 
    Details
    ISSN: 0091-7419
    Keywords: cytochalasin B derivative ; cell motility ; sugar transport ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Cytochalasin B (CB) is a potent inhibitor of sugar transport and cell motility in animal cells. We have synthesized and characterized the CB derivative 7-acetylcytochalasin B (CBAc) and have found that it has differential effects on transport and motile processes in fibroblasts. The derivative inhibited sugar transport in human red cells, 3T3 cells, and chicken embryo fibroblasts at micromolar concentrations, although it was less potent than its parent compound. Unlike CB, which causes fibroblasts to round up and arborize at less than 10 μM, CBAc had no effect on fibroblast morphology and membrane ruffling at concentrations as high as 90 μM. Competitive binding experiments using [3H] CB showed that the affinity of CBAc for sites related to sugar transport in the red cell membrane is about one-fourth of that of CB. In contrast, similar experiments using [3H] dihydrocytochalasin B (a derivative which inhibits cell motility but not sugar transport) showed that the affinity of CBAc for sites associated with red cell spectrin and actin is only about 1/20 of that dihydrocytochalasin B. This study demonstrates that acetylation of the C-7 hydroxyl group of CB reduces its effect on cell morphology and motility much more than its ability to inhibit sugar transport. This observation, together with our earlier work with dihydrocytochalasin B, establishes that the pharmacologic effects of CB on fibroblasts result from the binding of the drug to two distinct classes of receptors and that these receptors interact with different parts of the cytochalasin molecule.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120205
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  • 146
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    NMR of fd coat protein (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 139-145 
    Details
    ISSN: 0091-7419
    Keywords: fd coat protein ; 1H NMR ; 13C NMR ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The conformations of the major coat protein of a filamentous bacteriophage can be described by nuclear magnetic resonance spectroscopy of the protein and the virus. The NMR experiments involve detection of the 13C and 1H nuclei of the coat protein. Both the 13C and 1H nuclear magnetic resonance (NMR) spectra show that regions of the polypeptide chain have substantially more motion than a typical globular protein. The fd coat protein was purified by gel chromatography of the SDS solubilized virus. Natural abundance 13C NMR spectra at 38 MHz resolve all of the nonprotonated aromatic carbons from the three phenylalanines, two tyrosines, and one tryptophan of the coat protein. The α carbons of the coat protein show at least two different classes of relaxation behavior, indicative of substantial variation in the motion of the backbone carbons in contrast to the rigidity of the α carbons of globular proteins. The 1H spectrum at 360 MHz shows all of the aromatic carbons and many of the amide protons. Titration of a 1H spectra gives the pKas for the tyrosines.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110204
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    Properties of epithelial cells cultured from human carcinomas and nonmalignant tissues (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 147-166 
    Details
    ISSN: 0091-7419
    Keywords: carcinoma and nonmalignant cells ; fibronectin ; human epithelial cells ; plasminogen activator ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Human epithelial cell cultures were examined for expression of plasminogen activator and fibronectin matrix. All of the cells examined showed ultrastructural evidence suggesting their epithelial origin, including microvilli and specialized junctions. The nonmalignant cells were also negative for endothelial cell markers (ie, they lacked factor VIII antigen, a nonthrombogenic surface and Weibel-Palade bodies). The nonmalignant lines all produced large amounts of plasminogen activator, whereas the tumor-derived lines showed a gradation of activities, ranging from lines having as much activity as the nonmalignant lines to lines having little or no activity above background. For both normal and malignant cells, addition of dexamethesone only slightly decreased the levels of plasminogen activator. By immunofluorescence microscopy, normal bladder and fetal intestine epithelial cells showed fibronectin in a globular and fibrillar matrix. In contrast, normal mammary epithelial cells had a much diminished amount of fibronectin with a punctate distribution.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110205
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  • 148
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    Mitotic factors from mammalian cells: A preliminary characterization (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 189-195 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The objective of this study was the preliminary characterization of the factors from mitotic HeLa cells that can induce meiotic maturation in Xenopus laevis oocytes. We found that this factor is a heat-labile, Ca2+-sensitive, nondialyzable protein with a sedimentation value of 4-5S. Furthermore, no new protein synthesis was found to be required for this mitotic factor to induce maturation in the amphibian oocytes. These data suggest that the factors involved in the breakdown of nuclear membrane and the condensation of chromosomes that are associated with three different phenomena, mitosis, meiosis, and premature chromosome condensation, are very similar in different animal species.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110208
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    Pyrimidine biosynthesis in normal and transformed cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 197-205 
    Details
    ISSN: 0091-7419
    Keywords: pyrimidine biosynthesis ; V79 ; IARC19 ; IARC20 ; IARC28 ; biomarker ; pleiotropy ; confluence ; rat liver epithelial cells ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have developed procedures for sensitive measurement of specific radioactivities of pyrimidine nucleosides excreted from cells in culture. The changes in the observed values reflect dilution of the added isotope through de novo biosynthesis of nonradioactive pyrimidine nucleosides or by shifting and equilibration of other nucleotide pools into the free uridine pool. It is thus possible to monitor uridine biosynthesis occurring in intact cells without destroying or disrupting the cell population. On comparing a series of normal and transformed lines, we have observed several growth-dependent patterns of change in specific activity and levels of uridine excretion and the temporal appearance of these changes.Hamster embyro fibroblasts slows pyrimidine biosynthesis at mid-growth while the hamster cell line V79 continues to dilute the pyrimidine pool at about 7% of the rate observed during exponential growth at confluence. Both cells exhibit Urd excretion beginning at one-half maximal growth.Passageable normal rat liver cells (IARC-20) also show a cessation of pyrimidine biosynthesis with a prior increase in uridine excretion. Two chemically transformed lines IARC-28 and IARC-19 derived from IARC-20 show different patterns. IARC-19 begins uridine excretion in early log growth and the specific activity continues to decrease at about 2% of the rate observed during exponential growth at confluence. The IARC-28 cells also begin excretion in early log growth but pyrimidine biosynthesis stops at about midlog. This method may prove to be an additional aid in recognizing and differentiating transformed cells in culture that do not exhibit the transformed phenotype.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110209
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    Isolation and characterization of a variant of B16-mouse melanoma resistant to MSH growth inhibition (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 251-258 
    Details
    ISSN: 0091-7419
    Keywords: tumorigenicity ; cyclic AMP-dependent protein kinase ; tyrosinase MSH-growth-resistant variant ; mouse melanoma ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A variant of B-16 F1 mouse melanoma was selected for its ability to survive and replicate in the presence of melanocyte-stimulating hormone (MSH). Although the variant (MR-4) was completely resistant to growth inhibition by MSH, cyclic AMP was still able to block cell replication. Tyrosinase activity in MR-4 cells was considerably lower than in B-16 F1 cells. MSH induced a twofold to three-fold increase in tyrosinase activity in both cell types, but the absolute activity in MR-4 remained significantly less than in the parental cells. MR-4 cells were also found to have a markedly depressed cyclic AMP-dependent protein kinase activity relative to B-16 F1 cells. The protein kinase from both cell types was stimulated by cyclic AMP, but the level of MR-4 kinase activity at maximal cyclic AMP concentrations remained considerably lower than B-16 F1 kinase activity under the same conditions. In both cell types adenylate cyclase activity was markedly stimulated by MSH. When equal numbers of viable F1 and MR-4 cells were injected subcutaneously into C57/B1 mice, the MR-4 cells formed tumors earlier and killed the host sooner than the parental F1 cells. We conclude that the biochemical alteration which allows MR-4 cells to replicate in the presence of MSH is a low level of tyrosinase activity, which in turn may be the result of low cyclic AMP-dependent protein kinase activity.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110214
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    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110301
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    Erratum (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. i 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110302
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  • 153
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    Fibronectin associated with the glial component of embryonic brain cell cultures (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 269-281 
    Details
    ISSN: 0091-7419
    Keywords: fibronectin ; cell fractionation ; glial fibrillary acidic protein ; immunofluorescent labeling ; neuronal-glial cell interactions ; brain cell culture ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In a basic approach to investigations of neuronal-glial interactions during both normal brain development and its pathogenesis, embryonic brain cell populations were fractionated into purified neuronal and glial components. Using separation procedures based on differential adhesion and cytotoxicity, the isolated neuronal and glial phenotypes could be identified by distinct morphological and biochemical characteristics, including the visualization of glial fibrillary acid protein (GFA) within glial cells in immunohistochemical assays with monospecific anti-GFA serum.When unfractionated cerebrum cells dissociated from 10-day chick or 14-day mouse embryos were plated as monolayers and cultured for 1-14 days, monospecific antiserum against fibronectin (LETS glycoprotein) was found to react with many, but not all, of the cells as revealed by indirect immunofluorescence microscopy. The isolated neuronal and glial components of these populations were used to determine whether the appearance of membrane-associated fibronectin was characteristic of one cell type or the other, or both, and if neuronal-glial cell interaction was required for its expression. It was found that the surfaces of glial cells, completely isolated from neurons, showed an intense fluorescent reaction to the anti-fibronectin serum. In contrast, the purified neuronal cultures showed no fluorescence with either the anti-GFA or anti-fibronectin sera. These results demonstrate fibronectin as a cell surface protein associated primarily with glial cells and independent of neuronal-glial cell interaction for its expression. Furthermore, the results indicate that the fibronectin observed on glial cell surfaces in these cultures is produced endogenously and is not due to the preferential binding of fibronectin present in the culture medium. The role of fibronectin as an adhesive molecule in neuronal-glial interactions is discussed.
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    URL: http://dx.doi.org/10.1002/jss.400110216
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    Erratum (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 319-319 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110306
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    Specific interaction of cytochalasins with muscle and platelet actin filaments in vitro (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 283-293 
    Details
    ISSN: 0091-7419
    Keywords: cytochalasins ; muscle and platelet actin ; microfilaments ; cell motility ; viscosity changes ; electron microscopy ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The cytochalasins (CE, CD, CB and H2CB) inhibit numerous cellular processes which require the interaction of actin with other structural and contractile proteins. In this report we describe the effects of the cytochalasins on the viscosity and morphology of muscle and platelet actin. The cytochalasins decreased the viscosity of F-actin solutions. The effect of H2CB, CB and CD on F-actin viscosity was maximal at concentrations of 20-50μM and did not increase with time. In contrast, CE caused a progressive decrease in the viscosity of F-actin solutions which was dependent upon the concentration of CE and the duration of incubation of the CE-actin mixture. After two hours of incubation of drug-actin mixtures, the relative effectiveness of the cytochalasins in reducing the viscosity of F-actin was CE 〉 CD 〉 CB = H2CB. The effects of CD and CE were paralleled by morphologic changes in negatively stained actin filaments. The effects of the cytochalasins on the viscosity and morphology of muscle and platelet actin were the same whether the drugs were added before or after the polymerization of the protein.These studies show that the interaction of the cytochalasins with actin is highly specific. Because the relative potencies of these drugs for affecting motile processes and the relative affinities of the drugs for binding sites within a variety of cells are CE 〉 CD 〉 CB = H2CB, the effects of cytochalasins on actin described here may contribute to some of the biological effects of the drugs on motile processes.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110303
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    Fibronectin and proteoglycans as determinants of cell-substratum adhesion (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 401-427 
    Details
    ISSN: 0091-7419
    Keywords: fibronectin ; glycosaminoglycans ; proteoglycans ; adhesion ; substrate-attached material cytoskeleton ; immunofluorescence ; heparan sulfate ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: When normal or SV40-transformed Balb/c 3T3 cells are treated with the Ca++-specific chelator EGTA, they round up and pull away from their footpad adhesion sites to the serum-coated tissue culture substrate, as shown by scanning electron microscope studies. Elastic membranous retraction fibers break upon culture agitation, leaving adhesion sites as substrate-attached material (SAM) (Cells leave “footprints” of substrate adhesion sites during movement by a very similar process.) SAM contains 1-2% of the cell's total protein and phospholipid content and 5-10% of its glucosamine-radiolabeled polysaccharide, most of which is glycosaminoglycan (GAG). By one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, there is considerable enrichment in SAM for specific GAGs; for the glycoprotein fibronectin; and for the cytoskeletal proteins actin, myosin, and the subunit protein of the 10 nm-diameter filaments. Fibrillar fibronectin of cellular origin and substratum bound fibronectin of serum origin (cold-insoluble globulin, CIg) have been visualized by immunofluorescence microscopy. The GAG composition in SAM has been examined under different cellular growth and attachment conditions. Heparan sulfate content correlates with glycopeptide content (derived from glycoprotein). Newly attaching cells deposit SAM with principally heparan sulfate and fibronectin and little of the other GAGs. Hyaluronate and chrondroitin proteoglycans are coordinately deposited in SAM as cells begin spreading and movement over the substrate. Cells attaching to serum-coated or CIg coated substrates deposited SAM with identical compositions. The proteoglycan nature of the GAGs in SAM has been examined as well as the ability of proteoglycans to form two classes of reversibly dissociable “supramolecular complexes” - one class with heparan sulfate and glycopeptide-containing material and the second with hyaluronate-chondroitin complexes. Enzymatic digestion of “intact” SAM with trypsin or testicular hyaluronidase indicates that (1) only a small portion of long-term radiolabeled fibronectin and cytoskeletal protein is bound to the substrate via hyaluronate or chondroitin classes of GAG; (2) most of the fibronectin, cytoskeletal protein and heparan sulfate coordinately resist solubilization; and (3) newly synthesized fibronectin, which is metabolically labile in SAM, is linked to SAM by hyaluronate- and/or chondroitin-dependent binding. All of our studies indicate that heparan sulfate is a direct mediator of adhesion of cells to the substrate, possibly by binding to both cell-surface fibronectin and substrate-bound CIg in the serum coating; hyaluronate-chondroitin complexes in SAM appear to be most important in motility of cells by binding and labilizing fibronectin at the periphery of footpad adhesions, with subsequent cytoskeletal disorganization.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110314
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    Alkaline phosphatase of basal lateral and brush border plasma membranes from intestinal epithelium (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 451-466 
    Details
    ISSN: 0091-7419
    Keywords: alkaline phosphatase ; basal lateral membranes ; brush border membranes ; intestinal epithelium ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The alkaline phosphatases present on isolated brush border and basal lateral membranes of rat duodenal epitheilum were examined by means of a variety of biochemical assays and physical methods. The two alkaline phosphatases have similar pH optima of 9.6-9.8, similar substrate km's for p-nitrophenyl phosphate (PNPP) of 71 micromolar, similar responses to the inhibitors 2-mercaptoethanol, theophylline, phenylalanine, and ethylenediaminetetraacetic acid (EDTA), similar sensitivities to calcium, magnesium, zinc, sodium, and potassium, and similar insensitivities to digestion with trypsin or papain. The two enzymes also exhibit similar molecular weights on SDS-polyacrylamide gels in the range 124,000-150,000, and both enzymes show an Rf value of 0.092 on Triton X-100 polyacrylamide gels, indicating similar intrinsic charges. The Vmax of the brush border enzyme is ten times greater than that of the basal lateral enzyme, 140 μmoles/mg-h as opposed to 14 μmoles/mg-h. The differences in Vmax are a reflection of the known distribution of alkaline phosphatase in rat duodenum, there being more alkaline phosphatase activity present on the brush border than on the basal lateral surface. One other major difference was observed between the two enzymes, the stimulation of the basal lateral and not the brush border alkaline phosphatase by SDS, Triton X-100, or cholate. We conclude that the enzymes are very similar to one another and probably perform similar membrane functions.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110404
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    Selection of malignant melanoma variant cell lines for ovary colonization (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 517-528 
    Details
    ISSN: 0091-7419
    Keywords: cell variants ; electron microscopy ; malignant melanoma ; melanin ; metastasis ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Murine melanoma line B16-F1, which shows some specificity for metastatic organ colonization of lung but rarely metastasizes to ovary, was used to select variant cell lines with increased preference for experimental ovary metastasis. Ovary-colonizing melanoma cell lines were sequentially selected in syngeneic C57BL/6 mice by repeated intravenous administration and surgical recovery of ovarian melanoma tumors for tissue culture. After ten selections for experimental ovary metastasis, line B16-010 was established which formed experimental metastatic ovary tumors in almost every test animal. In tissue culture B16-010 cells grew in circular in circular colonies with rounded, smooth cell peripheries compared to B16-F1 cells which were flatter, grew in irregular patterns, and exhibited long cellular projections. Ovary-selected B16 lines contained less melainin pigment (B16-010 〈 B16-05 〈 B16-01 ≅ B16-F1) compared to the parental melanoma line. Together with previous cloning and selection data, these results are consistent with the preexistence of highly malignant cells in the parental tumor population that possess the ability to metastasize to specific organs.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110410
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    Solubilization and conversion of hepatic adenylate cyclase to a form requiring MnATP as substrate (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 31-37 
    Details
    ISSN: 0091-7419
    Keywords: adenylate cyclase ; liver ; solubilized ; MnATP ; MgATP ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A general feature of membrane-bound adenylate cyclase systems is the “lability” of the basal enzyme to dispersion by detergents. A stable form of the detergentsolubilized enzyme is obtained only if the membrane-bound enzyme is first pretreated with fluoride or Gpp(NH)p. However, we have found with the basal hepatic enzyme that the lability is evident primarily when MgATP is used as substrate; substitution of MnATP for MgATP reveals that substantial basal activity survives detergent treatment. This effect is independent of the detergent; it is seen with either Lubrol PX or with deoxycholate. In addition to the altered substrate requirement, the membrane-bound and solubilized forms of the basal enzyme exhibit other differences. In contrast to the membrane-bound form, the solubilized enzyme shows (1) weak stimulation by Gpp(NH)p; (2) little inhibition by adenosine, (3) strong inhibition by Pi or PPi, and (4) and apparent loss of the Me2+-reactive regulatory site. Such dissimilarities between membranebound and solubilized cyclase are not seen if the membranes are pretreated with Gpp(NH)p prior to exposure to detergents. The characteristics of the solubilized basal hepatic enzyme are similar to those of the naturally occurring soluble adenylate cyclase found in mature rat testes. It would appear that separation of adenylate cyclase from components that confer regulation by divalent cation and guanine nucleotides produces a form of the enzyme that will turnover only MnATP; this may represent the free catalytic moiety. Such preparations could be useful in reconstructing some of the regulatory functions of adenylate cyclase seen in its membrane-bound form.
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    URL: http://dx.doi.org/10.1002/jss.400100104
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    Tight junction development between cultured hepatoma cells: Possible stages in assembly and enhancement with dexamethasone (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 13-30 
    Details
    ISSN: 0091-7419
    Keywords: hepatoma ; cell culture ; tight junctions ; gap junctions ; freeze-fracture ; dexamethasone ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Freeze-fracture and thin-section methods were used to study tight junction formation between confluent H4-II-E hepatoma cells that were plated in monolayer culture in media with and without dexamethasone, a synthetic glucocorticoid. Three presumptive stages in the genesis of tight junctions were suggested by these studies: (1) “formation zones” (smooth P-fracture face ridges deficient in intramembranous particles), apparently matched across a partially reduced extracellular space, develop between adjacent cells; (2) linear strands and aggregates of 9-11 nm particles collect along the ridges of the formation zones. The extracellular space was always reduced when these structures were found matched with pits in gentle E-face depressions; (3) the linear arrays of particles on the ridges associate within the membranes to form the fibrils characteristic of mature tight junctions. The formation zones resemble tight junctions in terms of size, complexity and the patterns of membrane ridges. Although some of the beaded particle specialization may actually be gap junctions, it is unlikely that all can be interpreted in this way. No other membrane structures were detected that could represent developmental stages of tight junctions. Dexamethasone (at 2 × 10-6 M) apparently stimulated formation of tight junctions. Treated cultures had a greater number of formation zones and mature tight junctions, although no differences in qualitative features of the junctions were noted.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100103
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    Differences in the redistribution of concanavalin A and wheat germ agglutinin binding sites on mouse neuroblastoma cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 61-77 
    Details
    ISSN: 0091-7419
    Keywords: lectins ; binding sites ; neuroblastoma cells ; receptor redistribution ; cell surface labeling ; cytochalasin B ; concanavalin A ; wheat germ agglutinin ; fluorescent microscopy ; scanning electron microscopy ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Concanavalin A (Con A), wheat germ agglutinin (WGA), and Ricinus communis agglutinin (RCA) bound with either 125I, fluorescent dyes, or fluorescent polymeric microspheres were used to quantitate and visualize the distribution of lectin binding sites on mouse neuroblastoma cells. As viewed by fluorescent light and scanning electron microscopy, over 107 binding sites for Con A, WGA, and RCA appeared to be distributed randomly over the surface of differentiated and undifferentiated cells. An energy-dependent redistribution of labeled sites into a central spot occurred when the cells were labeled with a saturating dose of fluorescent lectin and maintained at 37°C for 60 min. Reversible labeling using appropriate saccharide inhibitors indicated that the labeled sites had undergone endocytosis by the cell. A difference in the mode of redistribution of WGA or RCA and Con A binding sites was observed in double labeling experiments. When less than 10% of the WGA or RCA lectin binding sites were labeled, only these labeled sites appeared to be removed from the cell surface. In contrast, when less than 10% of the Con A sites were labeled, both labeled and unlabeled Con A binding sites were removed from the cell surface. Cytochalasin B uncoupled the coordinate redistribution of labeled and unlabeled Con A sites, suggesting the involvement of microfilaments. Finally, double labeling experiments employing fluorescein-tagged Con A and rhodamine-tagged WGA indicate that most Con A and WGA binding sites reside on different membrane components and redistribute independenty of each other.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100107
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  • 162
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    Activation of cyclic AMP-dependent protein kinase and stimulation of protein phosphorylation in response to adenosine in C-1300 murine neuroblastoma (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 125-135 
    Details
    ISSN: 0091-7419
    Keywords: protein phosphorylation ; cAMP-dependent protein kinases ; adenosine on cyclic AMP ; C1300 neuroblastoma ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: DEAE-cellulose chromatography of the 20,000g supernatant fraction of homogenates of C-1300 murine neuroblastoma (clone N2a) yields one major and two minor peaks of cyclic AMP-dependent protein kinase activity. Assessment of the endogenous activation state of the enzyme(s) reveals that the enzyme is fully activated by the treatment of whole cells with adenosine (10 μM) in the presence of the phosphodiesterase inhibitor Ro 20 1724 (0.7 mM). This treatment produces a large elevation in the cyclic AMP content of the cells. The treatment of whole cells with adenosine alone (1-100 μM) or Ro 20 1724 alone (0.1-0.7 mM) produces minimal elevations in cyclic AMP but nevertheless causes significant activations of cyclic AMP-dependent protein kinase. The autophosphorylation of whole homogenates of treated and untreated cells was studied using [γ-32P] ATP, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Treatments which activate cyclic AMP-dependent protein kinase selectively stimulate the incorporation of 32P into several proteins. This stimulation is most prominent in the 15,000-dalton protein band. The addition of cyclic AMP to phosphorylation reactions containing homogenate of untreated cells stimulates the phosphorylation of the same protein bands. These results indicate that adenosine may have regulatory functions through its effect on the cyclic AMP: cyclic AMP-dependent protein kinase system.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100203
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    Relationship between steps in 8-anilino-1-naphthalene sulfonate (ANS) fluorescence and changes in the energized membrane state and in intracellular and extracellular adenosine 5′-triphosphate (ATP) levels following bacteriophage T5 infection of Escherichia coli (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 329-347 
    Details
    ISSN: 0091-7419
    Keywords: ANS fluorescence ; membrane hydration ; cholesterol ; phospholipid-cholesterol interaction ; infrared spectra ; red cell membranes ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The addition of bacteriophage T5 to anaerobic, fermenting cells of Escherichia coli B or K-12 in the presence of 8-anilino-1-naphthalene sulfonate (ANS), N-phenylnaphthyl-1-amine (NPN), or dansyl ethylamine causes the fluorescence of these probes to rise in two steps, the first occurring immediately upon addition, the second delayed by 6 min. The conditions necessary for observing this phenomenon are defined (cell density, probe concentration, substrate, absence of an electron acceptor, multiplicity of infection, growth, and harvesting conditions).The magnitudes of the first and second steps in fluorescence are dependent upon the multiplicity of infection; the timing of the steps is not. The first step correlates with a breakdown in the potassium or rubidium permeability barrier of the cell, and it occurs either aerobically or anaerobically, with fermentable or nonfermentable substrates. The second step occurs only with cells that are without an available electron acceptor, are fermenting, and which have a functional membrane-bound, Ca2+-Mg2+-dependent adenosine triphosphatase (ATPase). The results are consistent with disturbance of energization of the cell membrane by the membrane-bound ATPase at the time of the second step in fluorescence. No change in the intracellular level of adenosine 5′-triphosphate (ATP) was seen, whereas the extracellular level increased sharply, starting 3-6 min after phage addition. The quantity of ATP found in the medium by 30 min after infection amounted to about four times the amount present inside the cells at the time of infection. The quantity and rate of efflux of ATP was similar under aerobic and anaerobic conditions.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100305
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    Characterization of antigenic sialoglycoprotein subunits of the placental brush border membranes: Comparison with liver and kidney membrane subunits by two-dimensional electrophoresis (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 287-305 
    Details
    ISSN: 0091-7419
    Keywords: antigenic membrane glycoproteins ; immunoprecipitation ; two-dimensional electrophoresis ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The sialoglycoprotein subunits of human placental brush border membranes were labeled by sequential treatment with periodate and (3H)-sodium borohydride, which trititates sialic acid, and by lactoperoxidase-catalyzed (125I) iodination of tyrosine residues. The labeled subunits were characterized with respect to their affinity for antisera raised against Triton X-100 extracts of placental brush border membranes. The immunochemically reactive components were analyzed by two-dimensional electrophoresis according to a modification of the O'Farrell technique [20] enabling the assignment of estimated Mr̄ and pI. Of the 33 3H-labeled brush border subunits present in Triton X-100-solubilized membrane preparations, 18 subunits reacted with antiplacental brush border antisera insolubilized on CNBr-activated Sepharose or in immunoprecipitates. Fourteen of these tritiated subunits were also labeled with 125I, confirming that these are glycoproteins.The plasma membranes of normal human liver and microsomes from kidney were examined for the placental brush border glycoprotein subunits by reaction with insolubilized antiplacental brush border antisera and two-dimensional electrophoresis of the reacting tritium-labeled subunits. Comparison of the two-dimensional electrophoretic maps of the immunochemically reacting glycoproteins from liver, kidney, and placenta resulted in the identification of seven placental subunits in common with liver and kidney on the basis of antigenic cross-reactivity, Mr̄, and pI. Four placental glycoproteins were not found in the other tissues and are potentially specific to the placenta. Three of the placental subunits were only seen in placenta and kidney. Three of the subunits ran at the dye front and could not be assigned molecular weights. One of the subunits was poorly labeled by tritiation of sialic acid and was not considered.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100303
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    Carbohydrate structure of the major glycopeptide from human cold-insoluble globulin (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 391-399 
    Details
    ISSN: 0091-7419
    Keywords: cold-insoluble globulin ; carbohydrate structure ; human plasma ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Cold-insoluble globulin (CIg) is a member of a group of circulating and cell-associated, high-molecular-weight glycoproteins termed fibronectins. CIg was isolated from human plasma by affinity chromatography on gelatin-Sepharose. SDS-polyacrylamide gel electrophoresis of the purified glycoprotein gave a double band that migrated near myosin. The CIg glycopeptides were released by pronase digestion and isolated by chromatography on Sephadex G-50. Affinity chromatography of the major G-50 peak on Con A-Sepharose resulted in two fractions: one-third of the glycopeptides were unbound and two-thirds were weakly bound (WB). Sugar composition analysis of the unbound glycopeptides by GLC of the trimethylsilyl methyl glycosides gave the following molar ratios: sialic acid, 2.5; galactose, 3.0; N-acetylglucosamine, 4.9; and mannose, 3.0. Sugar composition analysis of the WB glycopeptides gave the following molar ratios: sialic acid, 1.7; galactose, 2.0; N-acetylglucosamine, 4.1; and mannose, 3.0. The WB CIg glycopeptides cochromatographed on Sephadex G-50 with WB transferrin glycopeptides giving an estimated molecular weight of 2,800. After degradation with neuraminidase alone or sequentially with β-galactosidase the CIg and transferrin glycopeptides again cochromatographed. Methylation linkage analysis of the intact and the partially degraded glycopeptides indicated that the carbohydrate structure of the major human CIg glycopeptide resembles that of the major glycopeptide from transferrin.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110313
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    Isolation and immunological characterization of an iron-regulated, transformation-sensitive cell surface protein of normal rat kidney cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 371-390 
    Details
    ISSN: 0091-7419
    Keywords: viral transformation ; iron starvation ; membrane proteins ; procollagen ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have analyzed the surface proteins of cultured normal rat kidney (NRK) cells and virus-transfromed NRK cells subjected to iron deprivation. Such a treatment specifically induces two transformation-sensitive plasma membrane-associated glycoproteins with a subunit molecular wegiht of 160,000 (160 K) and 130,000 (130 K) daltons in NRK cells. In these cells the 160 K glycoprotein is readily available to lactoperoxidase-mediated iodination, and the 130 K is apparently inaccessible to iodination. Major differences were revealed when iodinated membrane proteins of normal and virus-transformed cells subjected to iron deprivation were compared. In Kirsten sarcoma virus-transformed NRK cells the 160 K glycoprotein was weakly labeled. In two clones of simian virus 40-transformed NRK cells the 160 K glycoprotein was weakly labeled or not at all. The 130 K glycoprotein was inaccessible to iodination in all the virus-transformed cell lines.The 160 K and 130 K glycoproteins were isolated form plasma membranes of NRK cells using preparative SDS gel electrophoresis. Antibodies generated against these glycoproteins stained the external surfaces of NRK cells and induced antigen redistribution. Evidence presented suggests that 160 K and 130 K are plasma membrane-associated procollagen molecules. A possible interaction of these proteins with transferrin is also described. The data suggest that these proteins may have an important role in the sequence of events leading to transformation.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400110312
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    Subcellular fractionation of brown adipose tissue (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 445-449 
    Details
    ISSN: 0091-7419
    Keywords: subcellular fractionation ; brown adipose tissue ; plasma membranes ; microsomes ; Metrizamide ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The present study proposes a technique, using Metrizamide, which permits the preparation of brown adipose tissue plasma membranes from the crude mitochondria as well as from the crude microsome fraction. These plasma membranes have high relative specific activities of their marker enzyme, 5′-nucleotidase (15 ± 3 and 14 ± 2 respectively) and, particularly those originating in the crude microsomes, are relatively free of mitochondria contamination. This study also shows the influence of the mode of cell disruption on microsome integrity. When cell disruption was achieved by grinding in liquid nitrogen the purified microsome NADPH cytochrome c reductase specific activity was found to be 3.5 times greater than that of microsomes obtained after homogenization of the tissue.
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    URL: http://dx.doi.org/10.1002/jss.400110403
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    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100101
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    A possible modulation of acetylcholine receptors of embryonic chick muscle cells by α-bungarotoxin (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 39-50 
    Details
    ISSN: 0091-7419
    Keywords: muscle ; acetylcholine ; acetylcholine receptors ; α-Bungarotoxin ; chick ; modulation ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Acetylcholine receptors were assayed with α-bugarotoxin on embryonic chick skeletal muscle growing in primary cell culture. Toxin was bound specifically to muscle cells and could be competed with D-tubocurarine. Two dissociation constants were obtained by equilibrium binding: 7.2 × 10-9M and 2.7 × 10-7M at 25°C. Two sets of rate constants were also obtained from dissociation kinetics. There are five times more low affinity sites on cells than high affinity sites. The average density of high-affinity receptors is about 200/μm2.A time course of toxin binding to receptors at 37°C vs 25°C in growth medium revealed that under conditions permitting growth and metabolism, toxin bound to cells was lost. The possibility that the growth medium was in-activating toxin molecules was ruled out by showing that unbound toxin molecules in the medium were fully capable of binding to fresh cultures.
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    URL: http://dx.doi.org/10.1002/jss.400100105
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    Requirement for guanosine triphosphate in the activation of adenylate cyclase by cholera toxin (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 51-60 
    Details
    ISSN: 0091-7419
    Keywords: cholera toxin ; GTP ; pigeon erythrocyte ; adenylate cyclase ; cytosolic factor ; phosphodiesterase protein activator ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The activation of adenylate cyclase in lysed pigeon erythrocytes requires, among several cofactors, a nucleotide which may be ATP, GTP, or many other triphosphates. However, after removal of endogenous nucleotides by gel filtration or by adsorption onto charcoal the requirement can be met only by GTP, or an analog of GTP. The GTP is required during the activation of the cyclase by toxin even if GTP is also included during the subsequent adenylate cyclase assay, conducted without toxin. In the presence of GTP it is possible to assay for the cytosolic protein that is also required for the action of cholera toxin. By gel filtration, its apparent molecular weight is 15,000-20,000.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100106
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  • 171
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    Proteolytic cleavage and structural transformation: Their relationship in bacteriophage T4 capsid maturation (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 1-11 
    Details
    ISSN: 0091-7419
    Keywords: virus assembly ; limited proteolysis ; conformational change ; cooperativity ; electron microscopy ; optical diffraction ; computer image processing ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Giant T4 phage capsoids formed in canavanine-treated cultures infected by phage mutants in genes 21 and 17, respectively, differ with regard to cleavage of the major capsid protein, gp 23, and in the fine structure of their hexagonal surface lattices. Quantitative computer processing of electron micrographs shows that the significant differences in capsomer morphology amount to six symmetrically placed features present in the uncleaved hexamer but absent after cleavage. These features may be related with the N-terminal portions of gp 23 monomers excised by phage-specific proteolysis. Cleaved 17- giants can be induced to undergo a further structural transformation (expansion). Structural characteristics of partially transformed giant particles give clues about the dynamics of the cleavage and expansion transformations. Both processes appear to be polar, initiating in one cap and propagating along the particle. The transition zone of partial cleavage is diffuse, whereas the transition between unexpanded and expanded areas is confined to a narrow band of some 20 nm width.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100102
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  • 172
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    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100201
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  • 173
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    Growth factors and gangliosides: A possible new perspective in neuronal growth control (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 111-124 
    Details
    ISSN: 0091-7419
    Keywords: growth factors ; gangliosides ; neurogenesis ; cell developmental program ; neuronal cell lines ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: For many permanent cell lines the transition from a growing (P) to a resting (R) state is reversibly controlled by growth factors present in serum. This P-to-R transition was studied in a neuronal cell line (B 104) with respect to the action of serum, dibutyryl cyclic AMP (DBcAMP), gangliosides, and a glioma cell-produced growth factor GGF. In this cell system gangliosides seem to act as differentiation and survival factors. The kinetics of uptake of radioactively labeled gangliosides and survival experiments both support the idea of the stable incorporation of exogenously added gangliosides into the cells. Based on the experimental evidence a new model of cell development is proposed. Thus in addition to the R or G0 state, which in this cell system is rather unstable and probably regulated by cyclic nucleotides, we postulate a differentiated D state, which is controlled by gangliosides and which is characterized by its stability (survival time). This D compartment seems to be closer to the in vivo differentiated neuron than does the R or P state. The possible mechanisms for the action of gangliosides are discussed.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100202
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  • 174
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    Independence of the lethal actions of glucocorticoids on lymphoid cells from possible hormone effects on calcium uptake (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 165-174 
    Details
    ISSN: 0091-7419
    Keywords: glucocorticoids ; calcium ; thymus ; lymphosarcoma ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have examined the possibility that hormone-induced increases in calcium uptake might initiate the lethal actions of glucocorticoids in two types of lymphoid cells. Hormone-induced increases in nuclear fragility are used as the measure of hormone action, since in both rat thymus cells and in mouse P1 798 lymphosarcoma cells increased nuclear fragility (the inability of nuclei to survive lysis of the cells by hypotonic shock) precedes other indices of cellular deterioration by several hours.In the case of the tumor cells, those from corticosteroid-sensitive lines are less able to withstand incubation in vitro than resistant cells. Such differences in cell survival are predicted both by earlier changes in nuclear fragility and also by differences in calcium uptake. However, there is no detectable early glucocorticoid effect on calcium uptake that precedes or coincides with the substantial hormone-induced increases in nuclear fragility that develop in the sensitive cells by 2 h.In rat thymus cells the absence of calcium in the medium does prevent some of the increase in nuclear fragility and cell disintegration that occurs spontaneously during incubation in vitro. Nevertheless, when cells are exposed to hormones the glucocorticoid effect on nuclear fragility develops in the absence of calcium and is similar in magnitude to that seen in the presence of calcium.We conclude that calcium seems to enhance the spontaneous deterioration of lymphoid cells, and there is a large increase in calcium uptake that occurs as cells deteriorate. It nevertheless seems unlikely that hormone-induced changes in calcium uptake initiate the lethal actions of glucocorticoids. The data also support a proposal made earlier [2] that resistance to glucocorticoids in tumor cells may develop by the selection of cells with hardier membranes.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100206
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  • 175
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    Effect of metabolic inhibitors on vasopressin-stimulated transport systems in the toad bladder (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 175-184 
    Details
    ISSN: 0091-7419
    Keywords: vasopressin ; nocodazole ; urea transport ; rotenone ; dinitrophenol ; methylene blue ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Vasopressin increases the permeability of receptor cells to water and, in tissues such as toad bladder, to solutes such as urea. While cyclic AMP appears to play a major role in mediating the effects of vasopressin, there is evidence that activation of the water permeability system and the urea permeability system involves separate pathways. In the present study, we have shown that inhibitors of oxidative metabolism (rotenone, dinitrophenol, and methylene blue) selectively inhibit either vasopressin-stimulated water flow or vasopressin-stimulated urea transport. There was no inhibition, however, when exogenous cyclic AMP was substituted for vasopressin, and little to no inhibition when the potent analogue 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) was employed. Rotenone had no effect on adenylate cyclase activity or cyclic AMP levels within the cell; dinitrophenol decreased adenylate cyclase activity minimally.Additional studies with vinblastine and nocodazole, inhibitors of microtubule assembly, demonstrated an inhibition of vasopressin and cyclic AMP-stimulated water flow but showed no effect on urea transport.We would conclude that water and urea transport, as examples of hormone-stimulated processes, have different links to cell metabolism, and that in addition to cyclic AMP, a non-nucleotide pathway may be involved in the action of vasopressin.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100207
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  • 176
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    Properties of (Mg2+ + Ca2+)-ATPase of erythrocyte membranes prepared by different procedures: Influence of Mg2+, Ca2+, ATP, and protein activator (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 215-225 
    Details
    ISSN: 0091-7419
    Keywords: (Mg2+ + Ca2+)-ATPase ; erythrocyte membranes ; endogenous protein activator ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Erythrocyte membranes prepared by three different procedures showed (Mg2+ + Ca2+)-ATPase activities differing in specific activity and in affinity for Ca2+. The (Mg2+ + Ca2+)-ATPase activity of the three preparations was stimulated to different extents by a Ca2+-dependent protein activator isolated from hemolystes. The Ca2+ affinity of the two most active preparations was decreased as the ATP concentration in the assay medium was increased. Lowering the ATP concentration from 2 mM to 2-200 μM or lowering the Mg:ATP ratio to less than one shifted the (Mg2+ + Ca2+)-ATPase activity in stepwise hemolysis membranes from mixed “high” and “low” affinity to a single high Ca2+ affinity. Membranes from which soluble proteins were extracted by EDTA (0.1 mM) in low ionic strengh, or membranes prepared by the EDTA (1-10 mM) procedure, did not undergo the shift in the Ca2+ affinity with changes in ATP and MgCl2 concentrations. The EDTA-wash membranes were only weakly activated by the protein activator. It is suggested that the differences in properties of the (Mg2+ + Ca2+)-ATPase prepared by these three procedures reflect differences determined in part by the degree of association of the membrane with a soluble protein activator and changes in the state of the enzyme to a less activatable form.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100211
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  • 177
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    Internalization and processing of the EGF receptor in the induction of DNA synthesis in cultured fibroblasts: The endocytic activation hypothesis (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 199-214 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The addition of EGF to cultured murine 3T3 cells produces a decrease in EGF binding activity with concomitant internalization and degradation of the initially bound EGF. When the EGF receptor on cultured 3T3 cells is affinity labeled with high specific activity 125I-EGF, and the fate of the affinity labeled EGF-receptor complex determined, the loss in binding activity was accounted for by receptor internalization and subsequent proteolytic processing of the EGF receptor molecules in the lysosomes. Studies of the effects of EGF concentration on EGF binding by cells, EGF-induced receptor internalization and EGF-induced stimulation of 3H-thymidine uptake into cellular DNA show that there is a direct correlation between EGF-induced receptor internalization and EGF-induced stimulation of DNA synthesis, but not between EGF binding and EGF-induced stimulation of DNA synthesis. This correlation is lost at high EGF concentrations, where stimulation of DNA synthesis is suboptimal. Optimal stimulation of DNA synthesis requires a minimum of 6 h of incubation of EGF with cells, and the suboptimal stimulation of DNA synthesis at high EGF concentration is intensified when the period of incubation of EGF with cells is less than 6 h. These data are consistent with a model of hormone signal transmission by Endocytic Activation, wherein the activation of EGF-induced processes requires constant EGF-induced internalization of receptor for a requisite 6-8 h period as an obligatory step in production of “second messenger” in the action of this hormone.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400100210
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  • 178
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    Selective protein transport: Characterization and solubilization of the phosvitin receptor from chicken oocytes (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 491-504 
    Details
    ISSN: 0091-7419
    Keywords: oocyte protein transport ; receptor solubilization ; phosvitin receptor ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Phosvitin (PV), a subunit of a female-specific protein, vitellogenin, binds to oocyte membranes with a KD of 10-6 M. Binding reaches equilibrium within 30 min after incubation at 25°C. Bound 125I-PV dissociates from the membrane with a t1/2 of 13 h when incubated in buffer. However, when 125I-PV-labeled membranes are incubated in buffer containing 10-5 M unlabeled PV, 50% of the initially bound 125I-PV dissociates from the membrane within 10 min. These results support the conclusion that PV binds to a membrane-associated receptor.Solubilization studies show that Triton X-100 solubilizes up to 45% of the total membrane-bound 125I-PV. Gel-exculsion chromatography of the solubilized material yields a 500,000 dalton 125I-PV-containing complex separated from free 125I-PV. The 500,000 dalton complex completely dissociates to yield free 125I-PV when incubated with excess unlabeled PV. However, when incubated with (1) no addition, (2) IgG, or (3) serum albumin, the extent of dissociation is significantly reduced and is consistent with that which would be predicted on the basis of the observed dissociation rate in the absence of unlabeled PV.These results suggest that bound 125I-PV can only be displaced by unlabeled PV. These results also indicate that the 500,000 dalton species is a solubilized PV-receptor complex and that it is possible to solubilize the PV-receptor in an active form.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120409
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  • 179
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    Tumor cell surfaces and malignancy (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 161-231 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120506
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  • 180
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    T and B lymphocytes: Recognition and function (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 233-332 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120507
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  • 181
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    Structure of the dna binding cleft of the gene 5 protein from bacteriophage fd (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 457-465 
    Details
    ISSN: 0091-7419
    Keywords: DNA binding protein ; gene 5 ; fd bacteriophage ; X-ray diffraction ; protein-nucleic acid interactions ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The structure of the gene 5 DNA unwinding protein from bacteriophage fd has been solved to 2.3-Å resolution by X-ray diffraction techniques. The molecule contains an extensive cleft region that we have identified as the DNA binding site on the basis of the residues that comprise its surface. The interior of the groove has a rather large number of basic amino acid residues that serve to draw the polynucleotide backbone into the cleft. Arrayed along the external edges of the groove are a number of aromatic amino acid side groups that are in position to stack upon the bases of the DNA and fix it in place. The structure and binding mechanism as we visualize it appear to be fully consistent with evidence provided by physical-chemical studies of the protein in solution.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400100408
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  • 182
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    Structural and functional alterations in the surface of vascular endothelial cells associated with the formation of a confluent cell monolayer and with the withdrawal of fibroblast growth factor (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 73-114 
    Details
    ISSN: 0091-7419
    Keywords: fibronectin ; CSP-60 ; extracellular matrix ; thrombogenic properties ; low-density lipoprotein ; receptor redistribution ; asymmetry of cell surfaces ; cell morphology ; spatial configuration ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Vascular endothelial cells cultured in the presence of fibroblast growth factor (FGF) devide actively when seeded at low or clonal cell densities and upon reachin confluence adopt a morphologic appearance and differentiated properties similar to those of the vascular endothelium in vovi. In this review, we present some of our recent observations regarding the characteristics (both structural and functional) of these endothelial cells and the role of FGF in controlling their proliferation and normal differentation. At confluence the endothelial cells from a monolayer of closely apposed and nondividing cell that have a nonthrombogenic apical surface and can no longer internalize bound ligands such as low-density lipoprotein (LDL). The adoption of these properties is correlated and possibly causally related to changes in the cell surface such as the appearance of a 60,000 molecular weight protein (CSP-60); the disappearance of fibronectin from the apical cell surface and its concomitant accumulation in the basal lamina; and a restriction of the lateral mobility of various cell surface receptor sites. In contrast, endothelial cells that are maintained in the absence of FGF undergo within three passages alterations that are incompatible with their in vivo morphologic apperarance and physiologic beharior. They grow at confluence on top of each other and hence can no longer adopt both the structural (CSP-60, cell surface polarity) and functional (barrier function, nonthrombogenicity) attributes of differentiated endothelial cell. Since these characteristics can be reacquired in response to readdition of FGF, in addition to being a mitogen FGF may also be involved in controlling the differentitation and phenotypic expression of the vascular endothelium.
    Additional Material: 20 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120108
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  • 183
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    Biosynthesis of membrane glycoproteins in rat hepatoma tissue culture cells (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 151-164 
    Details
    ISSN: 0091-7419
    Keywords: membrane glycoproteins ; posttranslational modifications ; intracellular transport ; secretion ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The early steps in the biosynthesis of glycoproteins associated with the plasma membranes of rat hepatoma tissue culture cells has been analyzed. By measuring the effect of tunicamycin on the incorporation of [3H] mannose and [3H] fucose into cell glycoproteins, it was determined that an interval of about 1 h was required to transfer the glycoprotein from the site of mannosylation to the site of fucosylation. This result was corroborated by an analysis of the time required for the appearance of either mannose or fucose-labeled glycoproteins at the cell surface. The separation of membrane glycoproteins by a two-dimensional gel system allowed the visualization of the modifications leading to both size and charge heterogeneity of these proteins. By following the changes in electrophoretic mobility introduced into membrane glycoproteins during a chase period after a pulse labeling, the time course of these molecular alterations could be estimated. Several glycoproteins have apparently higher rates of synthesis than the bulk of membrane-associated glycoproteins. Most of these glycoproteins were released within 2 h after biosynthesis from the intracellular membrane fraction and appear after 3 h in the medium. In addition to the glycoproteins that contain both mannose and fucose and that show a high degree of charge heterogeneity, there are other membrane-bound species that are not noticeably modified by the in corporation of fucose or sialic acids. These glycoproteins could represent constituents limited to the internal membrane system of the HTC cell.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120202
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  • 184
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    Biosynthesis and maturation of cellular membrane glycoproteins (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 209-226 
    Details
    ISSN: 0091-7419
    Keywords: membrane glycoproteins ; human diploid fibroblasts ; BHK21 cells ; exoglycosidases and endoglycosidases ; asparaginyl-oligosaccharides ; gel filtration ; processing of oligomannosyl core ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The biosynthesis and the processing of asparagine-linked oligosaccharides of cellular membrane glycoproteins were examined in monolayer cultures of BHK21 cells and human diploid fibroblasts after pulse-and pulse-chase labeling with [2-3H] mannose. After pronase digestion, radiolabeled glycopeptides were characterized by high-resolution gel filtration, with or without additional digestion with various exoglycosidases and endoglycosidases. Pulse-labeled glycoproteins contained a relatively homogenous population of neutral oligosaccharides (major species: Man9GlcNAc2ASN). The vast majority of these asparagine-linked oligosaccharides was smaller than the major fraction of lipid-linked oligosaccharides from the cell and was apparently devoid of terminal glucose. After pulse-chase or long labeling periods, a significant fraction of the large oligomannosyl cores was processed by removal of mannose units and addition of branch sugars (NeuNAc-Gal-GlcNAc), resulting in complex acidic structures containing three and possibly five mannoses. In addition, some of the large oligomannosyl cores were processed by the removal of only several mannoses, resulting in a mixture of neutral structures with 5-9 mannoses. This oligomannosyl core heterogeneity in both neutral and acidic oligosaccharides linked to asparagine in cellular membrane glycoproteins was analogous to the heterogeneity reported for the oligosaccharides of avian RNA tumor virus glycoproteins (Hunt LA, Wright SE, Etchison JR, Summers DF: J Virol 29:336, 1979).
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120207
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  • 185
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    Masthead (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120301
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  • 186
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    Gliding mycoplasmas are inhibited by cytochalasin B and contain a polymerizable protein fraction (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 299-304 
    Details
    ISSN: 0091-7419
    Keywords: mycoplasma ; cytochalasin B ; actin-like protein ; cytoskeleton ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Studies are presented on the effect of cytochalasin B (CB) on the growth of five Mycoplasma species, three Acholeplasma species, and one Spiroplasma species. The three gliding mycoplasma species (M) gallisepticum, M pneumoniae and M pulmonis are the only mycoplasmas inhibited by CB. These are the only prolaryotes reported to be inhibited by CB. This suggested that these three mycoplasmas might have some sort of cytoskeletal structure. A protein fraction has been isolated from M gallisepticum which polymerizes in 0.6 M KC1 and depolymerizes when KC1 is removed. This fraction contains a major 58,000-dalton protein, a 46,000-dalton protein, and a minor 87,000-dalton protein.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120303
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  • 187
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    Ganglioside patterns of metastatic and non-metastatic transplantable hepatocellular carcinomas of the rat (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 485-492 
    Details
    ISSN: 0091-7419
    Keywords: carcinoma ; cell surface ; ganglioside ; hepatoma ; metastatis ; sialic acid ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In previous investigations, we correlated levels of sialic acid, gangliosides, and ganglioside glycosyltransferases with tumorigenesis over a 24-week continuum of growth of hepatocellular neoplasms of the rat induced by the carcinogen N-2-fluorenylacetamide. However, metastatic tumors developed only rarely and were not analyzed. To investigate surface changes associated with metastasis, well-differentiated and poorly differentiated hepatocellular carcinomas were transplanted to syngeneic recipient rats. From those, several metastatic and nonmetastatic isolates were obtained and compared. Both total and ganglioside sialic acid amounts in transplantable hepatomas were elevated above control liver values but were significantly lower for metastatic lines than for nonmetastatic lines. The nonmetastatic lines were characterized by ganglioside patterns depleted in the precursor ganglioside GM3 (sialic acid-galactose-glucose-ceramide) and elevated in the products of the monosialoganglioside pathway. In contrast, metastatic isolates exhibited a restoration of GM3 and nearer normal amounts of other gangliosides. The findings point to differences in sialic acid-containing glycolipids, comparing metastatic and nonmetastatic hepatocellular carcinomas, and further extend the concept that ganglioside alterations do not cause tumorigenesis but are the end result of a cascade of events which apparently continue beyond the onset of metastasis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110407
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  • 188
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    Isolation of cholera toxin receptors from a mouse fibroblast and lymphoid cell line by immune precipitation (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 273-291 
    Details
    ISSN: 0091-7419
    Keywords: cholera toxin-receptors ; cell growth ; glycolipids-transformation ; organization in membranes ; glycolipids as cell surface receptors ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Cholera toxin receptors have been isolated from both a mouse fibroblast (Balbc/3T3) and mouse lymphoid cell line labeled by the galactose oxidase borotritiide technique. Tritiated receptor-toxin complexes solubilized in NP40 were isolated by addition of toxin antibody followed by a protein A-containing strain of Staphylococcus aureus. In both cell types by far the major species of toxin receptor isolated was ganglioside in nature, although galactoproteins were also present in the immune complexes. Whether the galactoproteins form part of a toxin-receptor complex or are artifacts of the isolation procedure is presently unclear.The relative specificity of cholera toxin for a carbohydrate sequence in a glycolipid suggests that the toxin might prove a useful tool in establishing the function and organization of glycolipids in membranes. For example, interaction of cholera toxin with the mouse lymphoid cell line was shown to result in patching and capping of bound toxin, raising the possibility that the glycolipid receptor interacts indirectly with cytoskeletal elements. Cholera toxin might also be used to select for mutant fibroblasts lacking the toxin receptor and therefore having an altered glycolipid profile. Such mutants might prove useful in establishing the relationship (if any) between modified glycolipid pattern and other aspects of the transformed phenotype. Attempts to isolate mutants, based on the expectation that growth of cells containing the toxin receptor would be inhibited by the increase in cAMP levels normally induced by cholera toxin, proved unsuccessful. Cholera toxin failed to inhibit significantly the growth of either Balbc or Swiss 3T3 mouse fibroblasts although it markedly elevated cAMP levels.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jss.400120211
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  • 189
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    Comparison of the structures of human fibronectin and plasma cold-insoluble globulin (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 505-516 
    Details
    ISSN: 0091-7419
    Keywords: fibronectin ; cold-insoluble globulin ; carbohydrate content ; proteoglycan ; proteolytic cleavage ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Human amniotic fluid fibronectin and plasma fibronectin (cold-incoluble globulin) are indistinguishable both immunologically and by amino acid composition. Cyanogen bromide and tryptic peptides also suggest substantial structural homology. However, carbohydrate analysis has demonstrated additional saccharides in fibronectin and an overall increase in carbohydrate content relative to coldinsoluble globulin. Furthermore, limited proteolytic cleavage of the two proteins indicates differences in primary structure or in conformation. Using affinity-purified antibodies to cold-insoluble globulin, a glucosamine-labeled pronaseresistant component, probably proteoglycan, was found to coprecipitate with fibronectin, suggesting an association between these two macromolecules in the connective tissue matrix.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120410
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  • 190
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    Hormone-induced modification of EGF receptor proteolysis in the induction of EGF action (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 517-531 
    Details
    ISSN: 0091-7419
    Keywords: direct labeling of EGF receptors ; transient down-regulation of EGF receptors ; platelet derived growth factor ; receptor proteolysis ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A proposal that EGF action is mediated through enhanced internalization of EGF receptors is modified to account for more recent evidence. EGF receptors turn over at a rapid rate, and the maintenance of a steady state of EGF receptors on the cell surface is provided through a rapid synthesis of EGF receptors, balancing their removal. This rapid turnover of unoccupied receptors may arise through their removal. This rapid turnover of unoccupied receptors may arise through their internalization and proteolysis in the lysosomes, in much the same way as receptors are internalized and degraded when exposed to EGF, which enhances internalization. This provides a dilemma for the endocytic activation concept, since slight enhancement of receptor internalization gives rise to a strong hormone response. This problem may be solved by the observation that EGF induces a change in its receptor, exposing an otherwise unavailable site for proteolytic cleavage. This hormone-dependent modification of receptors may be the critical step in the induction of responses to EGF and other hormones that are internalized with their receptors. Both platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) are shown to down-regulate EGF receptors, though transiently, placing still more stringent requirements on the specificity by which hormones might act through endocytic activation of their receptors.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120411
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  • 191
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    Eucaryotic gene regulation (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 31-78 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400120503
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  • 192
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    A serological assay for the detection of cell surface receptors of nerve growth factor (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 9 (1978), S. 351-361 
    Details
    ISSN: 0091-7419
    Keywords: nerve growth factor ; receptors ; sensory ganglia cells ; brain cells ; serological receptor assay ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: When single-cell suspensions prepared from embroyonic day 8 (E8) chick sensory ganglia are incubated with nerve growth factor (NGF), anti-NGF antiserum, and complement, an NGF-dependent cytotoxic kill of 20 (±3)% of the ganglia cells is observed. This percentage is increased by a factor of two when only the neuronal cells are tested. No kill is observed on the nonneuronal cell population representing 50% of the ganglia dissociate. When E8 sensory ganglia cells are cultured in the presence of NGF following cytotoxic kill, the large, phase-bright NGF-reponsive neurons are missing from the culture. These results indicate that the cells recognized in the cytotoxicity assay have to carry NGF-binding sites of type I, which is the one with the higher affinity of the two types of NGF-binding sites (I and II) present on sensory ganglia cells. This conclusion is further supported by the following data: (a) half maximal cytotoxicity is reached already at a concentration of NGF which is below the KD of binding site I; (b) a washing step which removes all NGF bound to type II receptors while leaving a high percentage of type I receptors occupied has no effect on the percentage of ganglia cells killed.Using the cytotoxicity assay the presence of high-affinity binding sites of type I can be demonstrated on sensory ganglia cells from E8 chick embryos but not from E4 embryos and not on liver and heart cells from E8 embryos. Further, type I receptor-bearing cells were detectable in the brain using this assay. At E8, NGF receptors could be detected on cells of the forebrain and the tectum but not on brain stem cells. Cytotoxic kill of forebrain cells was found to be especially high at E8 and E9, and decreased by E10.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400090306
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  • 193
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    Photolabile and paramagnetic reagents for the investigation of transmembrane signaling events (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 9 (1978), S. 399-406 
    Details
    ISSN: 0091-7419
    Keywords: photoreactive probes ; ESR spin labels ; membranes ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: To investigate the dynamics of membrane processes that may be integral components of specific transmembrane signaling events we have synthesized several novel paramagnetic probes and their photoreactive counterparts. The structure of these probes was designed to (1) restrict “flipping” across the membrane bilayer; (2) contain paramagnetic or photoreactive moieties that could be placed at specific depths within the bilayer; (3) provide information about membrane structure as well as dynamics of protein movement; and (4) in the case of the photoreactive probes, be of high specific radioactivity.The molecules described in this paper consist of amino acid, dipeptide, or carbohydrate groups attached to arylazide- or nitroxide-bearing fatty acids. The synthesis and initial characterization of these membrane probes is described.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400090310
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  • 194
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    Masthead (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 9 (1978) 
    Details
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400090401
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  • 195
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    Effects of divalent-cation chelators and chloramphenicol on the spatial relationship of the nuclear envelope to chromatin in micronuclei of chinese hamster cells (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 9 (1978), S. 459-471 
    Details
    ISSN: 0091-7419
    Keywords: nuclear envelope-chromatin relationship ; chromosomes ; micronuclei ; mitochondria ; Colcemid ; EDTA and EGTA ; calcium magnesium ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In the presence of the spindle poison Colcemid in the culture medium to prevent anaphase, approximately 20% of Chinese hamster metaphase cells were converted to micronucleated cells during 7 h. In the micronuclei the chromosomes had become enclosed by a nuclear envelope (NE). In the light-microscope the micronuclei were of two kinds: with either visible chromatids or with decondensed chromosomes. In the electron microscope (EM) the spatial relationship of the NE to the chromatin was of two kinds only in the presence of Colcemid. In about 90% of the micronucleated cells the spatial relationship was normal, ie, the NE was immediately adjacent to the chromatin. In the remaining cells, the NE was distended so that the outer NE was separated from the inner one. In the presence of the drivalent cation chelator, (ethylenedinitrilo) tetraacetic acid (EDTA) or the Ca2+-chelator [ethylenebis (oxyethylenenitrilo)] tetraacetic acid (EGTA), in addition to Colcemid, the amount of cells with micronuclei increased to 40%. The light-microscope appearance was the same as that found in the absence of the chelating agents. However, after Colcemid plus EGTA, EM revealed that only about 50% of the micronucleated cells had NE that was immediately adjacent to the chromatin and about 10% of them had distended outer NE. In the remaining 40% a third kind of spatial relationship was seen: the NE was intact but most of it was not adjacent to the chromatin. Furthermore, this type of micronucleus often contained mitochondria within the confines of NE. Thus, Ca2+ and possibly Mg2+ may regulate the rate of formation of the NE and also its ultrastructural relation to the chromatin. Mitochondrial function also appears to be involved in this relationship. In the presence of chloramphenicol (CAP), an inhibitor of mitochondrial protein synthesis, in addition to Colcemid, only about 50% of the micronucleated cells exhibited the normal relationship. The outer NE was separated from the inner NE in about 46% of the micronucleated cells and the third kind of NE-chromatin relationship was observed only in 2%. In the case of the third kind of relationship produced by CAP, inclusion of mitochondria within the micronuclei was not observed, in contrast to the finding with EGTA.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400090402
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  • 196
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    Membrane alterations in irreversibly sickled cells: Hemoglobin-membrane interaction (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 9 (1978), S. 537-554 
    Details
    ISSN: 0091-7419
    Keywords: irreversibly sickled cells ; freeze-etching ; scanning electron micrography ; membrane-bound hemoglobin ; membrane proteins and glycoproteins ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Irreversibly sickled cells (ISCs) are sickle erythrocytes which retain bipolar enlongated shapes despite reoxygenation and owe their biophysical abnormalities to acquired membrane alterations. Freeze-etched membranes both of ISCs produced in vitro and ISCs isolated in vivo reveal microbodies fixed to the internal (PS) surface which obscure spectrin filaments. Intramembranous particles (IMPs) on the intramembrane (PF) surface aggregate over regions of subsurface microbodies. Electron microscopy of diaminobenzidine-treated ISC ghosts show the microbodies to contain hemoglobin and/or hemoglobin derivatives. Scanning electron microscopy and freeze-etching demonstrate that membrane-hemoglobin S interaction in ISCs enhances the membrane loss by microspherulation. Membrane-bound hemoglobin is five times greater in in vivo ISCs than non-ISCs, and increases during ISC production, paralleling depletion of adenosine triphosphate. Polyacrylamide gel electrophoresis of ISC membranes shows the presence of high-molecular-weight heteropolymers in the pre-band 1 region, a decrease in band 4.1 and an increase in bands 7, 8, and globin. The role of cross-linked membrane protein polymers in the generation of ISCs is discussed and is synthesized in terms of a unified concept for the determinants of the genesis of ISCs.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400090408
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  • 197
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    Immunochemical purification of probe-labeled plasma membrane proteins: An approach to the molecular anatomy of the cell surface (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 8 (1978), S. 39-49 
    Details
    ISSN: 0091-7419
    Keywords: affinity chromatography ; plasma membrane ; neoplastic transformation ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The probe 2,4,6-trinitrobenzene sodium sulfonate may be used under appropriate conditions for selective labelling of plasma membrane proteins exposed at the outer cell surface. Labeled proteins, solubilized by detergents, can be purified by reverse immunoadsorption using antiprobe antibodies covalently linked to Sepharose 4B. This method has been applied to an investigation of the outer cell surface structure of chicken embryo and hamster fibroblasts. Coelectrophoresis in sodium dodecyl sulfate-polyacrylamide gels of probe-labeled membrane proteins purified from baby hamster kidney fibroblasts have shown that 7 major protein groups of different molecular weight are exposed on both control and Rous sarcoma or polyoma virus-transformed cells. Moreover, the transformed cells display a nonvirion component of 80-100 k daltons that is not labeled by the probe in normal cells. In fibroblasts transformed by a temperature sensitive Rous sarcoma virus mutant, that transforms at 37°C but not at 41°C, the expression of this component is related to the expression of the transformed phenotype.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400080104
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  • 198
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    Temperature-dependent morphological changes in membranes of bacillus stearothermophilus (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 8 (1978), S. 129-138 
    Details
    ISSN: 0091-7419
    Keywords: freeze-fracturing ; membranes ; lipid phase separations ; B stearothermophilus ; temperature adaptation ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Bacillus stearothermophilus cells vary the lipid fatty acid composition of cytoplasmic membranes with growth temperature. Spin label studies of such membranes have been interpreted to indicate lateral lipid phase separations at the growth temperature. We have now used freeze-fracture electron microscopy to confirm the spin label studies. Freeze-fracture faces of protoplasts indicate slight but distinct protein aggregation at the growth temperature. Aggregation increases rapidly with decreasing quench temperature in wild-type cells. In contrast we were unable to demonstrate extended protein segregation in membranes of a temperature-sensitive mutant that contains more than 58% branched fatty acids.Storage of protoplasts for prolonged times below the lipid phase transition results in the appearance of corrugated fracture faces with 300- to 500-Å repeat patterns, although this organism does not synthesize lecithins.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400080203
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  • 199
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    Quantitative analysis of the microtubule system in isolated fish melanophores (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 8 (1978), S. 177-190 
    Details
    ISSN: 0091-7419
    Keywords: fish melanophores ; electron microscopy ; microtubules ; tubulin ; quantitative analysis ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Isolated melanophores of the angelfish, Pterophyllum scalare, have been used in a morphometric analysis and a quantitative study of their microtubule system. Using transverse sections spaced at regular intervals, the changes associated with the process of pigment aggregation have been determined. Upon the concentration of pigment granules in the central cell region, almost half of the cytoplasmic portion is also withdrawn from the peripheral cell regions. Counts of microtubules within a cell sector in cells with pigment aggregated and dispersed, respectively, reveal (a) a constancy of the number of microtubules in this sector regardless of the distance from the cell center, and (b) a reduction of microtubule number in cells with pigment aggregated by about 58%. On the basis of these counts, the total number of microtubules has been calculated. In the dispersed state, about 2,400 microtubules extend between the center and the periphery of the cell, while their number is about 1,000 in the aggregated state.Using a 13-protofilament model of a microtubule and relevant data on size and molecular weight of microtubule subunits, the amount of tubulin present as microtubules is calculated. In the average, the cells contain 1.95·108 monomers corresponding to 1.78·10-8 mg tubulin. A tentative estimation of the concentration of tubulin inside a melanophore yields values of 6.1 mg/ml for the whole cell and 16.5 mg/ml for the cytoplasm alone (excluding membrane-bound organelles). Based on this estimation, a comparison, with microtubule assembly in vitro is made.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400080207
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  • 200
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    Topology of amino-phospholipids in the red cell membrane (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 8 (1978), S. 191-213 
    Details
    ISSN: 0091-7419
    Keywords: amino-phospholipids ; chemical probes ; red cell membrane ; valinomycin ; ion transport ; membrane topology ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The red cell membrane has an asymmetric arrangement of phospholipids. The amino-phospholipids are localized primarily on the inner surface of the membrane and the choline phospholipids are localized to a large extent on the outer surface of the membrane. Evidence is presented based on the use of covalent chemical probes in sequence that the red cell membrane contains heterogeneous domains of PE and PS and that the transport systems for Pi and K+ are asymmetrically arranged. Certain amino groups of PE, PS, and/or protein localized on the outer membrane surface are involved in Pi transport and certain amino groups of PE, PS, and/or protein localized on the inner surface of the membrane are involved in K+ transport.Cross-linking studies with DFDNB show that the cross-linked PE-PE molecules are rich in plasmalogens. This suggests that clusters of plasmalogen forms of PE occur in the membrane. Both PE and PS are cross-linked to membrane protein. These PE and PS molecules contain 24-28% 16:0 and 18:0 fatty acids and 12% fatty aldehydes. PE and PS molecules are cross-linked to a spectrin-rich fraction. It is proposed that the binding of spectrin to membrane PE and PS may help anchor spectrin to the inner surface of the membrane and regulate shape changes in the cell.K+-valinomycin forms a complex with TNBS and converts it from a non-penetrating proble to a penetrating probe. Valinomycin enhances K+ leak and Pi leak in the red cells. SITS inhibits completely the valinomycin-induced Pi leak and inhibits partially the valinomycin induced K+ leak. Valinomycin and IAA have additive effects on Pi leak. Ouabin has no effect on basal or valino-mycin-induced Pi leak. These data suggest that Pi leak and K+ leak occur by separate transport systems.In summary, the amino-phospholipids in the red cell membrane are asymmetrically arranged; some occur in clusters and some are closely associated with membrane proteins. Amino-phospholipids also are believed to bind spectrin to the inner surface of the membrane and also may play a role in cation and anion leak.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400080208
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