bluuebunny/crossref_metadata_2025 huggingface dataset:
Stabilization of Interferon Messenger RNA Activity by Treatment of Cells with Metabolic Inhibitors and Lowering of the Incubation Temperature
Authors: Vilček Jan , Havell Edward A.
Published: May 2006

Interferon production was induced in a strain of human diploid foreskin cells with poly(I)·poly(C). Cycloheximide was included in the culture medium at the time of addition of the inducer. Actinomycin D was added to the cultures 4 or 5 hr later, before the inhibition of protein synthesis was reversed at 6 hr. Thus, subsequent interferon synthesis had to be directed by messenger RNA synthesized before addition of actinomycin D. The amount of interferon produced after such treatment was about 50-fold greater than in cells induced with poly(I)·poly(C) but not treated with inhibitors. Experiments using cordycepin suggested that in spite of the continued presence of the inducer the synthesis of the bulk of interferon messenger RNA was completed within the first 2 hr of exposure of cells to poly(I)·poly(C) and cycloheximide. Transcription of interferon messenger RNA was apparently not affected when interferon synthesis was suppressed to various degrees by different inhibitors of protein synthesis, indicating the independence of transcription and translation. The high rate of interferon synthesis after the reversal of cycloheximide action was more sustained at 32° than at 37°. The rate of decrease of overall protein synthesis in cells treated with actinomycin D and then incubated either at 32° or 37° showed a similar dependence on incubation temperature, suggesting that the stability of messenger RNA (or of another actinomycin D-sensitive component required for protein synthesis) was greater at the lower temperature.
Control of Normal Differentiation of Myeloid Leukemic Cells to Macrophages and Granulocytes
Authors: Fibach Eitan , Hayashi Makoto , Sachs Leo
Published: May 2006

Cells from a myeloid leukemic line in culture can be induced by the differentiation-inducing protein MGI to form colonies with normal differentiation to mature macrophages and granulocytes. This line consisted of clones that can be induced to undergo normal cell differentiation (D
+
clones) and clones (D
-
clones) that were not inducible. D
+
clones were able to undergo differentiation to both macrophages and granulocytes. Normal differentiation was induced even in clones that were no longer diploid. D
+
clones can segregate some D
-
progeny, and D
-
clones can segregate some D
+
progeny. This, therefore, provides a system for studies on the genetic and chemical control of cell differentiation in leukemic cells.
Mechanism of Action of Ribonuclease H Isolated from Avian Myeloblastosis Virus and
Escherichia coli
Authors: Leis Jonathan P. , Berkower Ira , Hurwitz Jerard
Published: May 2006

Purified preparations of RNA-dependent DNA polymerase isolated from avain myeloblastosis virus contain RNase H activity. Labeled ribohomopolymers are degraded in the presence of their complementary deoxyribopolymer, except [
3
H]poly(U)·poly(dA). The degradation products formed from [
3
H]poly(A)·poly(dT) were identified as oligonucleotides containing 3′-hydroxyl and 5′-phosphate termini, while AMP was not detected. The nuclease has been characterized as a processive exonuclease that requires ends of poly(A) chains for activity. Exonucleolytic attack occurs in both 5′ to 3′ and 3′ to 5′ directions.

RNase H has also been purified from
E. coli
. This nuclease degrades all homoribopolymers tested in the presence of their complementary deoxyribopolymers to yield oligonucleotides with 5′-phosphate and 3′-hydroxyl termini.
E. coli
RNase H has been characterized as an endonuclease.
Solvent Proton Magnetic Relaxation Dispersion in Solutions of Concanavalin A
Authors: Koenig Seymour H. , Brown Rodney D. , Brewer C. Fred
Published: May 2006

Concanavalin A, a protein isolated from jack beans, exhibits several important biological properties, all of which are related to its ability to bind and precipitate specific polysaccharides. Concanavalin A is a dimer at pH 5.6, and has one transition-metal and one calcium-ion binding site per monomer unit of molecular weight 27,000. Both metal-ion sites must be occupied for the protein to be active. It is of interest to determine the role of the transition metal ion in Concanavalin A and its relationship to the sugar binding activity of the protein.

We report the magnetic field and temperature dependences of the spin-lattice magnetic relaxation rates of solvent protons in aqueous solutions of zinc and manganese derivatives of Concanavalin A, and the influence of monosaccharide binding on these rates. The results of a leastsquares fit of the data to the theory, with five adjustable parameters, indicate that there is one rapidly exchanging water molecule ligand on the Mn
2+
ion, with a residence lifetime of 2.5 μsec at 25°, and with its protons 0.27 nm (2.7 Å) from the Mn
2+
ion. We find that at low magnetic fields (proton Larmor frequencies below about 10 MHz), the correlation time for the dipolar interaction between the Mn
2+
electronic spin moment and the protons on the water ligand is the spin-lattice relaxation time τ

S

of the Mn
2+
moment, but that at higher magnetic fields the correlation time for the dipolar interaction is determined by the Brownian rotational tumbling of the protein, because of the substantial variation of τ

S

with magnetic field. Monosaccharide binding to manganese Concanavalin A has little effect on the relaxation rates of solvent protons, a result that indicates that the sugars do not bind directly to the transition metal in the protein.
Mechanism of Interferon Uptake in Parental and Somatic Monkey-Mouse Hybrid Cells
Authors: Chany C. , Grégoire A. , Vignal M. , Lemaitre-Moncuit J. , Brown P. , Besançon F. , Suarez H. , Cassingena R.
Published: May 2006

Dose-response curves of interferons in different sensitive cells are regularly sigmoidal. In somatic monkey-mouse hybrid cells, however, a significant decrease in the slope of the curve for primate interferon was observed, while the dose-response effect was unaltered for mouse interferon. High concentrations of primate interferon were 10- to 100-times less effective in hybrid clones than in parental monkey CV-1 cells; at low concentrations the antiviral effect was 10- to 20-times higher in hybrid clones than in the parental cells. The receptor(s) for primate interferon located on the cell membrane was destroyed by trypsin but not by EDTA. Similarly, acid pH inactivated these receptor sites. We, thus, postulate that the antiviral effect is, at least partially, related to the amount of interferon taken up by the cells. Uptake could be conditioned by active cooperation of two cell-specific factors: a receptor and an activator. The activator might be missing or inactivated for primate interferon in the hybrid cells. We suggest that the putative antiviral protein is not cell-species specific, and that information for its synthesis in the hybrid cells might be located on a mouse rather than a monkey chromosome.
Hydrophobic Chromatography: Use for Purification of Glycogen Synthetase
Authors: Shaltiel Shmuel , Er-El Zvi
Published: May 2006

A homologous series of ω-aminoalkylagaroses [Sepharose-NH(CH
2
)

n

NH
2
] that varied in the length of their hydrocarbon side chains was synthesized. This family of agaroses was used for a new type of chromatography, in which retention of proteins is achieved mainly through lipophilic interactions between the hydrocarbon side chains on the agarose and accessible hydrophobic pockets in the protein.

When an extract of rabbit muscle was subjected to chromatography on these modified agaroses, the columns with short “arms” (
n
= 2 and
n
= 3) excluded glycogen synthetase (EC 2.4.1.11), but the enzyme was retained on δ-aminobutyl-agarose (
n
= 4), from which it could be eluted with a linear NaCl gradient. Higher members of this series (e.g.,
n
= 6) bind the synthetase so tightly that it can be eluted only in a denatured form. A column of δ-aminobutyl-agarose, which retained the synthetase, excluded glycogen phosphorylase (EC 2.4.1.1), which in this column series and under the same conditions requires side chains 5-(or 6)-carbon-atoms long for retention. Therefore, it is possible to isolate glycogen synthetase by passage of muscle extract through δ-aminobutyl-agarose, then to extract phosphorylase by subjecting the excluded proteins to chromatography on ω-aminohexyl-agarose (
n
= 6). On a preparative scale, the synthetase (I form) was purified 25- to 50-fold in one step.

This paper describes some basic features and potential uses of hydrophobic chromatography. The relevance of the results presented here to the design and use of affinity chromatography columns is discussed.
Chromosome Structure as Revealed by a Combined Chemical and Immunochemical Procedure
Authors: Schreck R. R. , Warburton D. , Miller O. J. , Beiser S. M. , Erlanger B. F.
Published: May 2006

Human metaphase chromosomes were photooxidized in the presence of methylene blue, a process that destroys guanine residues in DNA. Indirect immunofluorescence showed that such chromosomes reacted with a cytosine-specific antibody revealing a consistent fluorescent banding pattern by which each chromosome could be identified. The observed fluorescent patterns were the reverse of those produced in formamide-denatured chromosomes treated with an antibody specific for adenine and of the patterns obtained with quinacrine and with Giemsa staining by the G-banding techniques. The patterns were identical to Giemsa R-banding patterns. The chromosome banding patterns, therefore, appeared to reflect DNA base composition, indicating the feasibility of a combined chemical-immunochemical investigation of the chemical organization of chromosomes.
Isolation of the Self-Regulated Repressor Protein of the
Hut
Operons of
Salmonella typhimurium
Authors: Hagen David C. , Magasanik Boris
Published: May 2006

In
Salmonella typhimurium
the structural genes of the enzymes responsible for histidine utilization (
hut
) are clustered in two adjacent operons. A single repressor regulates both operons. The repressor itself is a member of one of the
hut
operons and, thus, regulates its own synthesis. We have assayed the
hut
repressor by its ability to bind radioactive DNA to nitrocellulose filters. The binding is specific for DNA bearing the
hut
operons, and the binding is abolished by the inducer, urocanate. As a member of one of the
hut
operons, the repressor is inducible, subject to catabolite repression, and affected by a promoter mutation.
Human Anti-IgM Iso-Antibodies: Detection of IgM Allotypic Markers
Authors: Wells J. Vivian , Bleumers Jan F. , Fudenberg H. Hugh
Published: May 2006

IgG class antibodies against human IgM were detected in a human subject up to a titer of 1:1024 against 5 of a group of 23 monoclonal Waldenström macroglobulins. Inhibition studies confirmed at least one antigenic determinant shared by the 5 IgMs. The determinant was present on the μ chain but required tertiary structure for its full expression. Inhibition of the reaction between the antibodies to IgM and erythrocytes coated with 2 of the 5 IgMs was obtained at titers of 1:2 to 1:16 with 51.0% of 300 normal sera (85.2% of sera from 122 Caucasian, 26.1% of sera from 23 Negro, and 27.7% of sera from 155 Japanese individuals). This inhibition was independent of the serum IgM concentration. Family studies indicated that the determinant was inherited according to basic Mendelian laws and appears to be the first allotypic marker on human serum IgM. We have designated it Mm 1.
A Type-C Virus in Human Rhabdomyosarcoma Cells After Inoculation into NIH Swiss Mice Treated with Antithymocyte Serum
Authors: Todaro George J. , Arnstein Paul , Parks Wade P. , Lennette Edwin H. , Huebner Robert J.
Published: May 2006

A type-C RNA virus has been isolated that replicates readily in human and other primate cells. It was obtained from a human rhabdomyosarcoma cell (RD) that had been serially transplanted in immunosuppressed NIH Swiss mice, a strain of mouse from which infectious type-C virus has not been isolated. Various other human tumor cells, similarly transplanted, remained free of overt type-C virus expression. The virus growing in the RD cells, AT-124, has a group-specific antigen and an RNA-dependent DNA polymerase immunologically related to murine type-C viruses, but a host range similar to that of the RD-114 virus. The new isolate is either a previously undescribed, endogenous type-C virus from NIH Swiss mice or a recombinant with both mouse and human type-C genetic information.
Transductional and Structural Principles of the Mitochondrial Transducing Unit
Authors: Green David E. , Ji Sungchul
Published: May 2006

The electromechanochemical model has been reformulated to take account of the close connection between energy coupling and catalysis. In catalysis the protein is programmed to utilize thermal energy to produce local strains in the catalytic cavity and to generate conformational states that favor substrate → product conversion. Energy coupling involves transfer of vibrational energy through the protein. Underlying these two energy transductional maneuvers is the concept of a pulsating protein capable of redistributing electromechanochemical potential energy in a programmed fashion. The mitochondrial supermolecule has been defined, and it has been shown how the supermolecule concept rationalizes the coupling options, the stoichiometry of the coupling complexes, and the multistep character of electron transfer.
Effect of Hemin on the Synthesis of Hemoglobin and Other Proteins in Mammalian Cells
Authors: Beuzard Yves , Rodvien Robert , London Irving M.
Published: May 2006

The initiation of globin synthesis in intact reticulocytes and in reticulocyte lysates is maintained by the addition of hemin. The specificity of this effect has been studied to determine whether it is restricted to hemoglobin and erythroid cells. In intact reticulocytes, hemin (500 μM) enhances the synthesis of carbonic anhydrase as well as of hemoglobin. Similar enhancement of protein synthesis is observed on addition of hemin (500 μM) to intact Krebs II ascites tumor cells, in cell-free extracts of these cells, added hemin (50 μM) increases endogenous protein synthesis and the translation of exogenous rabbit globin messenger RNA. These results provide evidence that the effect of hemin is not restricted to globin, and they suggest that hemin may enhance protein synthesis in at least some nonerythroid cells.
Nonvirion Antigens Produced by Herpes Simplex Viruses 1 and 2
Authors: Tarro Giulio , Sabin Albert B.
Published: May 2006

Of nine herpes simplex virus 1 strains (from lip, mouth, throat, cornea, or brain) only five produced enough nonvirion antigen (i.e., not a structural component of the virus) to be detected by complement fixation with specially prepared, virion-absorbed, type-1 guinea pig antisera, while the remaining four strains produced only enough of the same antigen to induce specific antibody in hyperimmunized guinea pigs. While the type 1 virion antiserum used reacted equally well by complement fixation with the type 1 and type 2 strains, the type 1 nonvirion antisera failed to react with nonvirion antigens produced by three type-2 (genital) strains. However, type 2 nonvirion antiserum reacted equally well with the three type 2 and four type 1 nonvirion antigens that were tested. It appears, therefore, that while herpes simplex virus 1 codes only for type 1 nonvirion antigen, herpes simplex 2 codes not only for an immunologically distinct type 2 nonvirion antigen but also for enough type 1 nonvirion antigen to stimulate antibody production for it.

Herpes simplex 2 nonvirion antigen exhibited the same properties as type 1, i.e., its activity was lost on storage at 4° for 15 days, it was sedimented by centrifugation at 33,360 ×
g
for 1 hr, and the maximum concentration was found at 3 hr in guinea pig kidney culture cells, but at 24 hr in HEp 2 and rabbit kidney culture cells. Sera from patients with genital lesions caused by herpes simplex virus 2, as well as from randomly selected adults, failed to react with either type 2 or type 1 nonvirion antigens. Accordingly, the basic information is now available to permit the use of these nonvirion antigens to determine the possible role of the herpes simplex viruses in certain human cancers.
Purification of Mouse Interferon by Affinity Chromatography on a Solid-Phase Immunoadsorbent
Authors: Sipe Jean D. , De Maeyer-Guignard Jaqueline , Fauconnier Bernard , De Maeyer Edward
Published: May 2006

A solid-phase immunoadsorbent capable of binding mouse interferon has been prepared. Starting from crude tissue-culture material, interferon could be purified 1990 times in a single step of affinity chromatography. Overall recovery ranged from 55 to 103% with tissue culture and mouse-brain interferon; however, only 5% was obtained with Sendai virus-induced interferon from mouse serum.
Ly-4
, A New Locus Determining a Lymphocyte Cell-Surface Alloantigen in Mice
Authors: Snell George D. , Cherry Marianna , McKenzie Ian F. C. , Bailey Donald W.
Published: May 2006

A new locus is described that determines an alloantigen on the surface of lymphocytes. It differs from loci previously described in that the corresponding antibody, at least in most antisera, reacts almost exclusively with node lymphocytes, and weakly or not at all with thymuslymphocytes. Positive strains include C57BL/6, C57BL/10, C57L, C57BR/cd, and RF; negative strains include BALB/c, C3H, and SJL. The symbol
Ly-4
is assigned, with the C57BL/6 allele being
Ly-4
b
, and the BALB/c allele
Ly-4
a
.
Isolation of Messenger RNA Coding for Mouse Heavy-Chain Immunoglobulin
Authors: Stevens R. H. , Williamson A. R.
Published: May 2006

A method for purification of the mRNA coding for heavy-chain protein of a mouse G
2a
myeloma (5563) is reported. Complete myeloma protein (H
2
L
2
) specifically binds to the heavy-chain mRNA, and the resultant RNA-protein complex is precipitated with antiserum against 5563 myeloma protein. Cytoplasmic RNA isolated by this method showed two bands of 6.0 × 10
5
and 3.1 × 10
5
molecular weight when analyzed by acrylamide gel electrophoresis. The RNA in the bands contained 1.5% and 8% A-rich regions, respectively. The RNA in each of the bands contained sequences for heavy-chain protein when translated in
Xenopus laevis
oocytes.
Genetic Regulation of Octane Dissimilation Plasmid in
Pseudomonas
Authors: Chakrabarty A. M. , Chou G. , Gunsalus I. C.
Published: May 2006

The enzymes responsible for the oxidation of
n
-octane to octanoic acid or beyond in
Pseudomonas oleovorans
are octane inducible and are coded by genes borne on a transmissible extrachromosomal element. The octane to octanoate enzymes induced by octane are repressed by octanol. The chromosome also carries genes coding octanol oxidation enzymes that, in contrast, are induced by octanol, not by octane. The octane plasmid has been transferred from
P. oleovorans
to several other fluorescent
Pseudomonas
species. In exconjugants, the presence of both octane and camphor plasmids enhances their segregation rate.
Discriminating Neoantigenic Differences Between Fibrinogen and Fibrin Derivatives
Authors: Plow Edward F. , Edgington Thomas S.
Published: May 2006

Discrimination between the physiological cleavage fragments of fibrinogen and fibrin offers an approach to differentiation between fibrinogenolytic processes and fibrinolysis after coagulation. By use of the cleavage-associated neoantigen of fibrinogen (fg-D
neo
) as a molecular marker, characteristic differences between the D regions of fibrinogen derivatives and fibrin derivatives can be demonstrated. The expression of fg-D
neo
by X, Y, D:E complex, and D-fragments of fibrinogen or fibrin is shown to be quantitative and unitary. Characteristic differences between fg-D
neo
sites present on fibrinogen cleavage fragments, as contrasted to fibrin cleavage fragments, are indicated by different competitive inhibition slopes, and appear to reflect differential binding affinity of selected anti-fg-D
neo
antibodies for the specific molecular site. There is a linear relationship between the slope of quantitative competitive inhibition and the relative molar ratio of fibrinogen and fibrin derivatives. Identical immunochemical expressions are observed
in vitro
and
in vivo
, and support the thesis that cleavage
in vivo
is produced by plasmin. The differential immunochemical features of fg-D
neo
expression may be the result of stable conformational and/or subtle structural differences between the D region of fibrinogen and fibrin cleavage fragments and suggest that precise changes in the D region are associated with the fibrin transition. These molecular features not only provide additional insight into the molecular immunology and structure of fibrinogen, but also appear to offer a new molecular approach to discrimination between fibrinogenolytic mechanisms as contrasted to fibrinolysis secondary to coagulation.
Partial Inhibition of Polysomal Ribosomes of
Escherichia coli
by Streptomycin
Authors: Wallace Brian J. , Tai P.-C. , Herzog Eugene L. , Davis Bernard D.
Published: May 2006

With purified initiation-free polysomes of
E. coli
, whether endogenous or formed
in vitro
on phage R17 RNA, streptomycin causes partial inhibition of chain elongation. The degree of inhibition is constant over a broad range of streptomycin concentration and decreases markedly with increasing Mg
++
concentration. Hence, streptomycin evidently complexes readily with polysomal ribosomes, causing a partial block in chain elongation.

Streptomycin has already been shown to cause a complete block of chain elongation by free ribosomes forming initiation complexes in its presence. The production of a different effect on polysomal ribosomes explains how streptomycin can exert two mutually exclusive effects in cells: phenotypic suppression at low concentrations and irreversible inhibition of protein synthesis at higher concentrations. It also becomes possible to understand why killing by streptomycin is antagonized by agents (such as chloramphenicol) that cause a stable blockade of the ribosomes in polysomes.
Cats Reared in Stroboscopic Illumination: Effects on Receptive Fields in Visual Cortex
Authors: Cynader M. , Berman N. , Hein A.
Published: May 2006

Cats were reared in a light-tight box in which the only source of illumination was a 9-μsec strobe flash every 2 sec. This allowed them to experience visual form but they did not experience visual movement. Receptive-field properties of single units in area 17 of the visual cortex of cats reared in stroboscopic illumination (strobe-reared) were compared with properties of units in area 17 of normally reared cats. In strobe-reared cats both direction selectivity and orientation selectivity were greatly reduced relative to normally reared cats, and some units in the strobe-reared cats responded only to strobe flashes.
Differential Transport of Protein in Axons: Comparison Between the Sciatic Nerve and Dorsal Columns of Cats
Authors: Anderson Larry E. , McClure William O.
Published: May 2006

Fast axoplasmic transport was studied in dorsal root ganglion cells of the cat. Proteins carried in the fast axoplasmic flow were labeled after an intraganglionic injection of
L
-[4,5-
3
H]leucine. The rate of transport was 380 ± 26 mm/day in both the central and peripheral branches of the bifurcating axons that arise from cells of the dorsal root ganglion. The amount of radioactivity transported centrally, through the dorsal roots into the spinal cord, was about 50% of that moving peripherally, through the sensory fibers of the sciatic nerve. Labeled material appears to be transported principally in a bound form, as 70-80% of the radioactivity was insoluble in 0.01 M potassium phosphate buffer at pH 7.4. With multiple extractions, a fractionation procedure was developed by which 94-96% of the total transported radioactivity could be solubilized. The proteins carried by fast axoplasmic transport through the dorsal columns and through the sciatic nerve were compared by electrophoresis of extracted fractions on Na dodecyl sulfate-polyacrylamide gels. Different patterns of radioactivity are seen in the electrophoretograms, suggesting that the cells of the dorsal root ganglion may possess the ability to commit different proteins to transport through two branches of a single bifurcating axon.
A Tumor Antigen in Tissue Cultures Derived from Patients with Hodgkin's Disease
Authors: Long John C. , Aisenberg Alan C. , Zamecnik Mary V. , Zamecnik Paul C.
Published: May 2006

Pellets obtained from supernatant fluids of monolayer cultures of cells from patients with Hodgkin's disease were fractionated by isopycnic density sedimentation. Material in a peak of specific gravity 1.15-1.21 g/ml from two Hodgkin's disease cultures was used to immunize rabbits, and the antisera obtained in this manner were reacted by agar-gel diffusion and immunoelectrophoresis with antigens from the purified peaks and the unfractionated pellets of centrifuged culture medium from all the cultures. The antisera reacted with material from 9 of 10 lines derived from spleens of patients with Hodgkin's disease, 2 of 8 cell lines from histologically negative spleens from patients with Hodgkin's disease and with 3 of 6 lymphoma cell lines not diagnosed as Hodgkin's disease. The antisera did not react with 12 cell cultures prepared from normal adult and fetal spleen and thymus. The antigen from cultures from patients with Hodgkin's disease was not found in material sedimenting at lower specific gravities; it resisted Tweenether solubilization, and migrated as a single band by immunoelectrophoresis. The antigen was not found in disrupted, noncultured tumor cells from patients with Hodgkin's disease, and an antiserum against noncultured, minced tumor tissue did not react with the Hodgkin's disease tissue-culture material. No immunological relationship was found between the tissue culture antigen and Epstein-Barr, RD-114, or Rauscher murine leukemia viruses. The Hodgkin's disease antigen may be a tumorrelated antigen or a component of an oncogenic virus.
Response of
Dictyostelium
Plasma Membranes to Adenosine 3′:5′-Cyclic Monophosphate
Authors: Gregg James H. , Nesom Margaret G.
Published: May 2006

Myxamoebae of the cellular slime mold
Dicytostelium discoideum
aggregate in response to a chemotactic substance identified as adenosine 3′:5′-cyclic monophosphate. Upon aggregation cell division is suppressed, the cells become adhesive, and differentiation is initiated. Freeze-fracture studies of myxamoebae were conducted to determine the effect of cyclic AMP and calcium on plasma membrane ultrastructure. The inner surfaces of the plasma membranes exhibited particulate structures whose sizes (43-187 Å) and frequency distribution were determined. Cyclic AMP and calcium induced within 2 hr the formation of particles having average diameters 1.7-times and 1.5-times greater, respectively, than those of the vegetative myxamoebae controls. These data suggest that cyclic AMP mobilizes the intracellular calcium which may be effective in changing plasma membrane structure.
Cell Contact-Dependent Increase in Membrane D-Galactopyranosyl-Like Residues on Normal, But Not Virus- or Spontaneously-Transformed, Murine Fibroblasts
Authors: Nicolson Garth L. , Lacorbiere Monique
Published: May 2006

Ricinus communis
agglutinin (a lectin specific for β-D-galactopyranosyl-like oligosaccharide residues) was used to investigate differences in lectin-binding sites on normal 3T3 and transformed SV3T3 and 3T12 cells grown to various cell densities in culture. The agglutinability of SV3T3 cells by
R. communis
agglutinin decreased when cells were grown to confluency or to a point where the cells were in contact. The agglutinability of 3T3 cells also decreased at confluency, but this result was variable and not as dramatic as with SV3T3 cells. Saturation-binding experiments performed at 4° with
125
I-labeled
R. communis
agglutinin were used to monitor the number of lectin-binding sites on cells grown to different densities. Transformed cells (SV3T3 and 3T12) did not show cell-culture density-dependent changes in
R. communis
sites; sparse, touching, and confluent transformed cells had equivalent numbers of sites. However, touching (or confluent) 3T3 cells possessed 2.5-times the number of
R. communis
sites per cell compared to growing, sparsely populated 3T3 cells. When growing sparse 3T3 cells are compared to growing SV3T3 or 3T12 cells, there are 5-times
R. communis
sites per unit surface area on the transformed cells. The change in
R. communis
sites during cell growth in culture is discussed in relation to membrane fluidity and topography of plasma membrane oligosaccharides and glycosyl transferases, which can modify cell surfaces at contact.
Quantitative Deficiency of Chain-Specific Globin Messenger Ribonucleic Acids in the Thalassemia Syndromes
Authors: Housman David , Forget Bernard G. , Skoultchi Arthur , Benz Edward J.
Published: May 2006

A hybridization assay procedure was devised that makes possible quantitation of the ratio of mRNA of alpha to mRNA of beta globin chains in an RNA sample. The assay uses the radioactive synthetic DNA copies obtained by incubation of RNA-dependent DNA polymerase of avian myeloblastosis virus with rabbit globin mRNA that is 80-90% enriched in mRNA specific for synthesis of alpha or beta globin chains. The rabbit alpha-chain mRNA is obtained from the postribosomal supernatant of rabbit reticulocyte lysates; the rabbit beta-chain mRNA is obtained from the largest polysomes of rabbit reticulocytes treated with L-
O
-methylthreonine. Sufficient homology exists between rabbit and human globin chains and globin mRNAs that the synthetic DNA copies of chain-specific rabbit globin mRNA hybridize with human globin mRNA. Applied to the study of globin mRNA isolated from reticulocytes of humans with alpha and beta thalassemia, the technique revealed marked quantitative deficiency of alpha-chain mRNA relative to beta-chain mRNA in alpha thalassemia and similar deficiency of beta-chain mRNA relative to alpha-chain mRNA in beta thalassemia. The thalassemia syndromes are therefore characterized by true quantitative deficiency of the mRNA specific for the affected globin chain.
Protein Kinase Activity in Erythrocyte Ghosts of Patients with Myotonic Muscular Dystrophy
Authors: Roses Allen D. , Appel Stanley H.
Published: May 2006

Myotonic muscular dystrophy is a disorder of humans that involves many organ systems. Physiological studies have suggested that the fundamental defect is of membrane origin. Heretofore, no reproducible metabolic abnormalities have been demonstrated. In the present studies we used erythrocyte ghosts as a convenient source of purified membranes that do not possess changes of denervation, dystrophy, and fibrosis that might complicate the interpretation of muscle membrane changes. Our experiments demonstrated a significant difference in the phosphorylation of erythrocyte ghost protein by [γ-
32
P]ATP, with endogenous protein kinase of erythrocyte membrane as the enzyme source. After ghosts were kept for 1 week at -20°, phosphorylation of membrane protein in eight controls was twice as high as endogenous protein kinase activity measured in fresh preparations. No stimulation was seen in preparations from seven myotonic dystrophy patients from three different families. This reproducible difference in normal and myotonic membranes may represent an important new approach to studies of this debilitating inborn error of metabolism.
Genic Variability and Strategies of Adaptation in Animals
Authors: Selander Robert K. , Kaufman Donald W.
Published: May 2006

Levels of genic heterozygosity, as measured by surveys of allozymic variation, are much lower in populations of large, mobile animals (most vertebrates) than in those of small, relatively immobile animals (most invertebrates). This difference is not consistent with theories relating variability to population size (species number) or dispersal ability (gene flow), but it is predicted by Levins' theory of adaptive strategies in relation to environmental uncertainty (“grain”). Mobility and degree of homeostatic control apparently are important factors influencing levels of genic heterozygosity in natural populations. The results argue indirectly that at least a major proportion of allozymic variation is maintained by natural selection.
Common Cell-Surface Antigen Associated with Murine and Feline C-Type RNA Leukemia Viruses
Authors: Yoshiki Takashi , Mellors Robert C. , Hardy William D.
Published: May 2006

A new common cell-surface antigen associated with murine and feline C-type RNA leukemia viruses was demonstrated by the use of rabbit antiserum against feline leukemia virus and the indirect membrane immunofluorescence test. Common cell-surface antigen was found in all leukemias of all strains of mice tested, in normal lymphoid tissues of Gross-positive (high incidence of leukemia) mouse strains AKR, AKR·H-2
b
, C58, and NZB, in cultured rat fibroblasts infected with Rauscher virus, in cultured feline fibroblasts infected with feline leukemia virus, and in spontaneous feline lymphosarcoma. The antigen was not demonstrable in normal adult and fetal tissues of Gross-negative mouse strains or in tissues and cultured fibroblasts derived from normal rats and normal cats. The immunoferritin study of murine leukemia cells revealed that the antigen was located on the cell surface in discrete areas; budding and C-type RNA viral envelope was not labeled as antigen site. The distribution of common cell-surface antigen on murine and feline leukemias, as well as on normal lymphoid tissues of Gross-positive mouse strains, indicates the presence of an antigen distinct from any cell-surface antigen heretofore shown to be associated with, or specified by, mammalian C-type RNA viruses.
Equilibrium Potentials of Membrane Electrodes
Authors: Wang Jui H. , Copeland Eva
Published: May 2006

A simple thermodynamic theory of the equilibrium potentials of membrane electrodes is formulated and applied to the glass electrode for measurement of pH. The new formulation assumes the selective adsorption or binding of specific ions on the surface of the membrane which may or may not be permeable to the ion, and includes the conventional derivation based on reversible ion transport across membranes as a special case. To test the theory, a platinum wire was coated with a mixture of stearic acid and methyl-tri-
n
-octyl-ammonium stearate. When this coated electrode was immersed in aqueous phosphate solution, its potential was found to be a linear function of pH from pH 2 to 12 with a slope equal to the theoretical value of 59.0 mV per pH unit at 24°.
Herpes Simplex Virus as a Source of Thymidine Kinase for Thymidine Kinase-Deficient Mouse Cells: Suppression and Reactivation of the Viral Enzyme
Authors: Davidson Richard L. , Adelstein S. J. , Oxman Michael N.
Published: May 2006

Thymidine kinase (EC 2.7.1.21)-deficient mouse cells were infected with inactivated herpes simplex virus, after which “transformed” cells that produce viral thymidine kinase were isolated. Shortly after transformation, the expression of the viral enzyme could be suppressed and reactivated with high efficiency. On continued multiplication in nonselective medium, the proportion of cells producing the viral enzyme decayed exponentially. This decay seemed to represent a change in the expression of the viral gene for thymidine kinase rather than the loss of the gene from the cells, since the viral enzyme could be apparently reactivated in every cell, albeit at a very low frequency.
A Rat Mammary Carcinoma
In Vivo
and
In Vitro
: Establishment of Clonal Lines of the Tumor
Authors: Kano-Sueoka Tamiko , Hsieh Philip
Published: May 2006

Clonal cell lines from a pituitary hormone-dependent rat mammary carcinoma were established. The growth of these cell lines
in vitro
is markedly stimulated in the presence of prolactin. The cells grow well in a medium supplemented with fetal-calf serum (generation time: 9-10 hr), but do not grow with calf serum. Fetal-calf serum supports little growth when the serum is subjected to anti-prolactin-affinity chromatography. Gel filtration of fetal-calf serum indicates that the growth stimulatory activity is in a large molecular weight material (close to 100,000), suggesting that prolactin is associated with another serum component. A variant of the original tumor, which does not require hormone for growth, was obtained, and clonal cell lines of this tumor were also established. These cells, in contrast to the hormone-dependent ones, grow well with either fetal-calf serum (with or without anti-prolactin treatment) or calf serum.
Biological Versatility and Earth History
Authors: Vermeij Geerat J.
Published: May 2006

Examples from various plant and animal groups indicate that there has been a general increase in potential versatility of form, determined by the number and range of independently varying morphogenetic parameters, among taxa appearing at successively younger stages in the fossil record. Taxa or body plans with higher potential versatility have tended to replace less potentially versatile groups in the same or similar adaptive zone through time. Greater potential diversity allows for greater homeostasis, efficiency, and integration of structures and functions, and for an increase in size of the potential adaptive zone. In contrast, chemical versatility has generally decreased within groups from the pre-Cambrian to the Phanerozoic, partly as the result of apparent changes in the chemical environment and partly as the consequence of selection for efficiency and greater metabolic ease of handling of certain materials.
Effects of Selective Extraction of Histones on Template Activities of Chromatin by Use of Exogenous DNA and RNA Polymerases
Authors: Mirsky Alfred E. , Silverman Bert
Published: May 2006

Exogenous DNA and RNA polymerases were used to measure the template activity of DNA in chromatin in isolated thymus nuclei from which lysinerich or arginine-rich histones were selectively extracted. Measurements were on nuclei containing 20-1200 μg of DNA per ml, the distinctions becoming clear at the higher concentrations. Experiments with RNA polymerase showed only moderate increases in template activity upon extraction of histone, although the removal of lysinerich histone had a greater effect than that of arginine-rich histone. DNA polymerase action on nuclei minus lysinerich histone achieved high results, exceeding even those on DNA itself.
Intervent Dilution Chromatography: Concept for Separation of Strongly Interacting Macromolecules
Authors: Kirkegaard Leslie , Agee C. Coe
Published: May 2006

Intervent dilution chromatography separates interacting macromolecules by subjecting them to a dynamic environment in which the association constant is continuously varied. The dynamic environment is produced by using the sieving properties of a gel to repeatedly propel the molecular complex across an intervent boundary. Behind the boundary, at high intervent concentrations, the complex dissociates; ahead of the boundary, the component molecules are separated by adsorption processes. By selective adjustment of the intervent composition of the sample and the conditions of column equilibration, the process is adapted to a particular need. This report describes the chromatographic concept and shows how parameters are adjusted to obtain the desired separation. In this study a particularly difficult separation, i.e., the separation of ribosomal proteins from ribosomal RNA, is chosen to illustrate the power of the procedure.
Electron Carriers of Cytochrome Oxidase Detectable by Electron Paramagnetic Resonance and Their Relationship to Those Traditionally Recognized in This Enzyme
Authors: Hartzell Charles R. , Hansen Raymond E. , Beinert Helmut
Published: May 2006

On the basis of oxidoreductive rapid kinetic and titration experiments with purified cytochrome
c
oxidase (EC 1.9.3.1), monitored by electron paramagnetic resonance (EPR) at 13°K and by spectrophotometry at 100°K, a new assignment of EPR signals is proposed. The bulk of both the low-spin (
g
= 3.0; 2.2; 1.5) and highspin (
g
= 6; 2) signals is attributed to the component with the properties of traditional cytochrome
a
. It is further proposed that the absorption band at 655 nm represents the most unambiguous manifestation of the
a
3
component.
Allograft Tolerance: Presumptive Evidence That Serum Factors from Tolerant Animals That Block Lymphocyte-Mediated Immunity
In Vitro
Are Soluble Antigen-Antibody Complexes
Authors: Wright P. W. , Hargreaves R. E. , Bansal S. C. , Bernstein I. D. , Hellström K. E.
Published: May 2006

Serum factors present in rats rendered operationally tolerant to skin allografts by inoculation of allogeneic bone-marrow cells as newborns inhibit or “block” the cytotoxic effect of immune lymphocytes
in vitro
. These blocking factors were specifically removed from tolerant serum by absorption with allogeneic cells and later eluted from the absorbing cells in glycine buffer (pH 3.1). Blocking activity of the eluted material was resolved into fractions of low and higher molecular weight, which may be soluble histocompatibility antigen and specific alloantibody, respectively. Both antigen and antigen-antibody complexes may block
in vitro
, depending upon the assay used.
Mobility of Carbohydrate-Containing Structures on the Surfaces Membrane and the Normal Differentiation of Myeloid Leukemic Cells to Macrophages and Granulocytes
Authors: Inbar Michael , Ben-Bassat Hannah , Fibach Eitan , Sachs Leo
Published: May 2006

Clones (D
+
) of a cultured line of myeloid leukemic cells can be induced to undergo normal differentiation to mature macrophages and granulocytes. There are also clones derived from the same cell line (D
-
) that could not be induced to differentiate. The carbohydrate-binding protein concanavalin A was used as a probe to study the mobility of carbohydrate-containing sites on the surface membrane of these cells. Changes in the distribution of concanavalin A binding sites on the surface membrane can be induced by concanavalin A. With the appropriate site mobility, this induction of a new distribution resulted in a concentration of concanavalin A-membrane site complexes on one pole of the cell to form a cap. D
+
and D
-
clones showed 50 and 5% of cells with caps, respectively, although both types of cells bound a similar number of concanavalin A molecules. Treatment of cells with trypsin increased cap formation from 5 to 40% in D
-
cells, but did not change the percentage of cells with caps in D
+
cells. The results show a difference in the mobility of concanavalin A binding sites in these two types of cells and suggest a difference in the fluid state of these carbohydrate-containing structures on the surface membrane. It is suggested that a gain of the ability of myeloid leukemic cells to undergo normal differentiation is associated with an increase in the fluidity of structures on the surface membrane where the concanavalin A sites are located. Differences in fluidity of specific membrane sites may also explain differences in the response of cells to other differentiation-inducing stimuli.
Discriminatory Ribosome Rebinding of Isolated Regions of Protein Synthesis Initiation from the Ribonucleic Acid of Bacteriophage R17
Authors: Steitz Joan Argetsinger
Published: May 2006

To determine whether bacterial ribosomes recognize a distinguishing feature in the immediate vicinity of actual initiator codons or are directed to these sites through involvement of other portion(s) of the mRNA molecule, the interaction between ribosomes and defined
32
P-labeled initiator fragments from R17 RNA was studied. When incubated with mixtures of the three sites, ribosomes from
Bacillus stearothermophilus
(which initiate only the A protein on intact phage RNA) are able to select out the A fragment and discriminate against the coat and replicase initiator regions. By contrast,
Escherichia coli
ribosomes do not rebind that coat-protein region of R17 most efficiently, as they in the native RNA, but likewise prefer the A-protein initiator fragment. In both cases, ribosome binding of the isolated A site is comparable by several criteria to normal polypeptide-chain initiation on an intact R17 messenger RNA
in vitro
.
E. coli
ribosomal preference for the A site is confirmed in experiments with randomly fragmented R17 RNA, by both the initiation dipeptide and ribosome protection assay. Thus the A-protein ribosome-binding site of R17 RNA appears intrinsically to be a good initiator, while efficient recognition of the coat and replicase regions requires the participation of some portion of the remainder of the phage RNA molecule.
Complete Amino-Acid Sequence of Actin of Rabbit Skeletal Muscle
Authors: Elzinga Marshall , Collins John H. , Kuehl W. Michael , Adelstein Robert S.
Published: May 2006

The complete amino-acid sequence of actin of rabbit skeletal muscle was determined. The actin polypeptide chain is composed of 374 residues, including one residue of the unusual amino acid N
r
-methyl histidine, and has a calculated molecular weight of 41,785. The sequence of actin was determined by isolating the peptides produced by cleavage of the protein with cyanogen bromide, determining the sequence of these peptides, and establishing their order within the molecule. This study represents the first complete determination of the aminoacid sequence of a myofibrillar protein. Comparison of this sequence with peptides from actins isolated from different sources indicates that the sequence of actin is highly conserved.
Differential Metabolism of Large and Small Poly(A) Sequences in the Heterogeneous Nuclear RNA of HeLa Cells
Authors: Nakazato Hiroshi , Edmonds Mary , Kopp David W.
Published: May 2006

The heterogeneous RNA of the HeLa cell nucleus contains short internal poly(A) sequences which, in contrast to the longer poly(A) sequences at the 3′ ends, are not found in messenger RNA of the cytoplasm. A distinct origin for each of these homologous sequences is evident when the effects of actinomycin D and 3′-deoxyadenosine on their biosynthesis are compared. The shorter poly(A) appears to be transcribed, while the longer one does not. A kinetic analysis of the metabolism of each type of poly(A) sequence within different size classes of HnRNA after treatment of the cells with 3′-deoxyadenosine reveals distinctive distribution and metabolism of these sequences and also provides insight into mechanisms proposed for the generation of messenger RNA from these large RNA molecules in the nucleus.
Transformation of Cultured Mammalian Cells by Viable Herpes Simplex Virus Subtypes 1 and 2
Authors: Garfinkle B. , McAuslan B. R.
Published: May 2006

A continuous line of rodent cells carrying the genome of the Rous sarcoma virus was stably transformed by exposure to viable herpes simplex virus of either subtype 1 or 2. Transformation was accompanied by alteration of morphology, growth characteristics, acquisition of a thymidine kinase activity (EC 2.7.1.21) resembling the corresponding specific activity of the enzyme in the herpes simplex virus, and capacity to express continuously some antigens specific for herpes simplex virus.
Molecular Complementarity of Yeast Glycoprotein Mating Factors
Authors: Crandall Marjorie , Lawrence Lawrence M. , Saunders Robert M.
Published: May 2006

Cell fusion between opposite mating types
5
and
21
of the yeast
Hansenula wingei
is initiated by a strong sexual agglutination reaction. The mating factors responsible for the specificity of cellular recognition are complementary glycoproteins which form a physical complex
in vitro
. The complex is assayed by recovery of agglutination activity of the multivalent 5-factor after the univalent 21-factor has been inactivated by treatment of the complex with alkali. The 5-factor·21-factor complex, purified on Sepharose 6B, is large (several million daltons) and heterogeneous. The three peaks of 5-factor activity contain a number of combining sites proportional to molecular size.