Normal immunoglobulin M—II. The molecular weights of the intact molecule and its tryptic and reductive fragments

1973 ◽  
Vol 10 (10) ◽  
pp. 689-694 ◽  
Author(s):  
J.D. Conradie ◽  
L. Visser
Keyword(s):  
Immunoglobulin M ◽  
Molecular Weights ◽  
Intact Molecule

scholarly journals FOURTH COMPONENT OF HUMAN COMPLEMENT: DESCRIPTION OF A THREE POLYPEPTIDE CHAIN STRUCTURE

1974 ◽  
Vol 140 (5) ◽  
pp. 1324-1335 ◽  
Author(s):  
Robert D. Schreiber ◽  
Hans J. Müller-Eberhard
Keyword(s):  
Disulfide Bonds ◽  
Periodic Acid ◽  
Chain Structure ◽  
Original Method ◽  
Human Complement ◽  
Periodic Acid Schiff ◽  
Molecular Weights ◽  
Intact Molecule ◽  
Fourth Component ◽  
Polypeptide Chains

The fourth component of human complement (C4) was shown to be composed of three distinct polypeptide chains linked by disulfide bonds and noncovalent forces. The sum of the molecular weights of the chains equalled that of the intact molecule. The mol wt of the α-, ß-, and γ-chains were respectively, 93,000, 78,000, and 33,000 daltons. Action of C1s on C4 affected only the α-chain, reducing its mol wt to 87,000 daltons. The size of the activation peptide. C4a, is therefore estimated to be 6,000 and that of the major fragment C4b, 198,000 daltons. Periodic acid-Schiff-stained SDS polyacrylamide gels of reduced C4 revealed carbohydrate to be associated with all three chains. A modification of the original method of isolation of C4 is presented.

Analysis of the thermal transition curves of deoxyribonucleic acid from microorganisms

1970 ◽  
Vol 16 (10) ◽  
pp. 989-995 ◽  
Author(s):  
R. E. Krieg ◽  
W. R. Lockhart
Keyword(s):  
Base Composition ◽  
Thermal Denaturation ◽  
Deoxyribonucleic Acid ◽  
Size Range ◽  
Thermal Transition ◽  
Molecular Fragments ◽  
Frequency Distributions ◽  
Molecular Weights ◽  
Intact Molecule ◽  
Transition Curves

The thermal transition of sheared deoxyribonucleic acid (DNA) may reveal differing nucleotide frequencies within individual fragments, which is a crude reflection of nucleotide sequence in the intact molecule. DNA samples from seven species were characterized at three molecular weights, encompassing a size range from about one one-hundredth to one ten-thousandth of the original molecules. Thermal denaturation curves were treated as cumulative frequency distributions of individual molecular fragments differing in average base composition. Thermal transition curves of individual DNA samples show characteristic deviations from normality, which indicates that the proportions of nucleotides in some DNA fragments differ considerably from the average for the intact molecule. The statistical values describing denaturation curves are characteristic and constant for DNA from a given organism and are different and distinctive for different organisms.

The covalent assembly of MOPC 104E immunoglobulin M. Identification of a heavy chain dimer, a complex of two heavy chains and one light chain, and a distinctive form of monomer as intracellular intermediates

1978 ◽  
Vol 56 (3) ◽  
pp. 190-196 ◽  
Author(s):  
Maire E. Percy ◽  
Arnold Feinstein ◽  
Reuben Baumal
Keyword(s):  
Heavy Chain ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Tumour Cells ◽  
Immunoglobulin M ◽  
Heavy Chains ◽  
Molecular Weights ◽  
Chain Dimer ◽  
Sds Page ◽  
Mouse Myeloma

The covalent assembly of MOPC 104E immunoglobulin M (IgM) was studied in mouse myeloma tumour cells producing a twofold molar excess of light chains (L's), using pulse-chase and continuous-label experiments with radioactive amino acids. In previous experiments with myeloma tumour cells which produced a large excess of L's, the half molecule (HL) was the only intermediate identified as a precursor of the intracellular monomer (LHHL). In the current experiments, heavy chain dimer (HH) and a disulfide-bonded intermediary containing two H chains and one L chain (HHL) also functioned as precursors of the monomeric subunit. These experiments indicate that the degree of excess L production by the tumour cells appears to influence the amounts of intracellular intermediates, and that MOPC 104E IgM assembles via the same pathways which are utilized in the assembly of mouse immunoglobulin G (IgG). On sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS–PAGE), the radiolabelled intracellular monomer which was synthesized by the mouse myeloma tumour cells in culture migrated slightly more slowly than the monomeric subunit liberated from MOPC 104E IgM by reduction with low concentrations of dithiothreitol. The distinctive mobility of the intracellular monomer did not result from the presence of radiolabelled, disulfide-bonded joining (J) chain. In addition, the apparent molecular weights of the constituent heavy IgM chain (μ) and L's of the intracellular monomer, as judged by SDS–PAGE, were not significantly different from those of secreted μ and L.

scholarly journals Mass Transport of Macromolecules within an In Vitro Model of Supragingival Plaque

2003 ◽  
Vol 69 (3) ◽  
pp. 1702-1709 ◽  
Author(s):  
Thomas Thurnheer ◽  
Rudolf Gmür ◽  
Stuart Shapiro ◽  
Bernhard Guggenheim
Keyword(s):  
Laser Scanning ◽  
Bulk Water ◽  
Immunoglobulin M ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Streptococcus Sobrinus ◽  
Molecular Weights ◽  
Supragingival Plaque ◽  
Depth Analysis

ABSTRACT The aim of this study was to examine the diffusion of macromolecules through an in vitro biofilm model of supragingival plaque. Polyspecies biofilms containing Actinomyces naeslundii, Fusobacterium nucleatum, Streptococcus oralis, Streptococcus sobrinus, Veillonella dispar, and Candida albicans were formed on sintered hydroxyapatite disks and then incubated at room temperature for defined periods with fluorescent markers with molecular weights ranging from 3,000 to 900,000. Subsequent examination by confocal laser scanning microscopy revealed that the mean square penetration depths for all tested macromolecules except immunoglobulin M increased linearly with time, diffusion coefficients being linearly proportional to the cube roots of the molecular weights of the probes (range, 10,000 to 240,000). Compared to diffusion in bulk water, diffusion in the biofilms was markedly slower. The rate of diffusion for each probe appeared to be constant and not a function of biofilm depth. Analysis of diffusion phenomena through the biofilms suggested tortuosity as the most probable explanation for retarded diffusion. Selective binding of probes to receptors present in the biofilms could not explain the observed extent of retardation of diffusion. These results are relevant to oral health, as selective attenuated diffusion of fermentable carbohydrates and acids produced within dental plaque is thought to be essential for the development of carious lesions.

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Electron Microscopic identification of Pre-B Lymphocytes in the Bone Marrow of a Patient with Chronic Myelocytic Leukemic in Blast Crisis

1982 ◽  
Vol 40 ◽  
pp. 346-347
Author(s):  
T. Mullin ◽  
G. Yee ◽  
M. Aheam ◽  
J. Trujillo
Keyword(s):  
Blast Crisis ◽  
Immunoglobulin M ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Transformation Theory ◽  
Electron Microscopic ◽  
Chemotherapeutic Sensitivity ◽  
Microscopic Studies ◽  
Hematopoietic Precursor ◽  
Lymphoblastic Transformation ◽  
B Lineage

There have been numerous reports in the current literature suggesting that hematopoietic precursor cells in some human chronic myelocytic leukemias (CML) undergo lymphoblastic transformation at the time of the acute blast crisis (BC) stage. The primary evidence offered in support of this transformation theory--lymphoblastic appearing morphology, increased terminal deoxynucleotidyl transferase (TdT) activity, and chemotherapeutic sensitivity to vincristine and prednisone--has been indirect, however, since these features may occur in nonlymphoid cells. More direct support for the Pre-B lineage of these cells has recently been provided by immunofluorescent light microscopic studies demonstrating the presence of intracytoplasmic immunoglobulin M (IgM) in these CML-BC cells.

Characterization of microtubules by dark-field STEM and replication

1991 ◽  
Vol 49 ◽  
pp. 152-153
Author(s):  
S.B. Andrews ◽  
R.D. Leapman ◽  
P.E. Gallant ◽  
T.S. Reese
Keyword(s):  
Protein Interactions ◽  
Low Dose ◽  
Unit Length ◽  
Dark Field ◽  
Carbon Films ◽  
Microtubule Associated Proteins ◽  
Molecular Weights ◽  
Freeze Dried ◽  
Protein Motors ◽  
Associated Proteins

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen (ca. -185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled to ca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.

Electron Microscope Study of RNA's of Paramyxoviruses

1972 ◽  
Vol 30 ◽  
pp. 196-197
Author(s):  
Ruchama Baum ◽  
J.T. Seto
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Sendai Virus ◽  
Sodium Dodecyl ◽  
Rna Molecules ◽  
Virus Particles ◽  
Molecular Weights ◽  
Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

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