On the mycophage of Penicillium chrysogenum

1973 ◽  
Vol 19 (1) ◽  
pp. 97-103 ◽  
Author(s):  
C. H. Nash ◽  
R. J. Douthart ◽  
L. F. Ellis ◽  
R. M. Van Frank ◽  
J. P. Burnett ◽  
...  
Keyword(s):  
Ribonucleic Acid ◽  
Penicillium Chrysogenum ◽  
Thermal Denaturation ◽  
Buoyant Density ◽  
Ion Concentration ◽  
Contour Length ◽  
Viral Dsrna ◽  
Viral Particles ◽  
Profile Characteristic ◽  
Isopycnic Centrifugation

A mycovirus has been purified from mycelia of Penicillium chrysogenum by isopycnic centrifugation in sucrose and in CsCl. Viral particles band with a buoyant density of 1.20 in sucrose and 1.38 in CsCl. Particles have icosohedral symmetry, are 35 nm in diameter, and have an absorption profile characteristic of nucleoprotein. One enzymatic activity, RNA polymerase, is associated with the purified mycophage. Nucleic acid extracted from purified virus has a buoyant density in CS2SO4 of 1.61, a molar extinction coefficient of εp (258 nm) of 7200, a s20, w of 13.0, and a pattern of circular dichroism characteristic of double-helical ribonucleic acid. Molecules of this double-stranded ribonucleic acid (dsRNA), examined by electron microscopy, have a mean contour length of 0.86 μm which corresponds to a molecular weight of about 2.0 × 106 daltons. This dsRNA is resolved further by acrylamide gel electrophoresis into three closely spaced bands. Thermal denaturation of the viral dsRNA is dependent on ionic strength and gives a linear relationship with the negative logarithm of the sodium ion concentration.

Existence of DNA in yeast microbodies

1978 ◽  
Vol 36 (2) ◽  
pp. 232-233
Author(s):  
Masako Osumi ◽  
Misuzu Nagano ◽  
Hiroko Kazama
Keyword(s):  
Catalase Activity ◽  
Buoyant Density ◽  
Model System ◽  
Contour Length ◽  
Native State ◽  
Normal Alkane ◽  
Remarkable Increase ◽  
Dna Molecule ◽  
Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

scholarly journals An antiserum specific for cholinergic synaptic vesicles from electric organ.

1980 ◽  
Vol 87 (1) ◽  
pp. 98-103 ◽  
Author(s):  
S S Carlson ◽  
R B Kelly
Keyword(s):  
Synaptic Vesicle ◽  
Synaptic Vesicles ◽  
Membrane Fraction ◽  
Motor Nerve ◽  
Buoyant Density ◽  
Electric Organ ◽  
Rabbit Serum ◽  
Antigenic Determinants ◽  
Nerve Terminals ◽  
Isopycnic Centrifugation

Rabbit antisera to highly purified synaptic vesicles from the electric organ of Narcine brasiliensis, an electric ray, reveal a unique population of synaptic vesicle antigens in addition to a population shared with other electric organ membranes. Synaptic vesicle antigens were detected by binding successively rabbit antivesicle serum and radioactive goat anti-rabbit serum. To remove antibodies directed against antigens common to synaptic vesicles and other electric organ fractions, the antivesicle serum was extensively preadsorbed against an electric organ membrane fraction that was essentially free of synaptic vesicles. The adsorbed serum retained 40% of its ability to bind to synaptic vesicles, suggesting that about half of the antigenic determinants are unique. Vesicle antigens were quantified with a radioimmunoassay (RIA) that utilized precipitation of antibody-antigen complexes with Staphylococcus aureus cells. By this assay, the vesicles, detected by their acetylcholine (ACh) content and the antigens detected by the RIA, have the same buoyant density after isopycnic centrifugation of crude membrane fractions on sucrose and glycerol density gradients. The ratio of ACh to antigenicity was constant across the vesicle peaks and was close to that observed for vesicles purified to homogeneity. Even though the vesicles make up only approximately 0.5% of the material in the original homogenate, the ratio of acetylcholine to vesicle antigenicity could still be measured and also was indistinguishable from that of pure vesicles. We conclude that synaptic vesicles contain unique antigenic determinants not present to any measurable extent in other fractions of the electric organ. Consequently, it is possible to raise a synaptic vesicle-specific antiserum that allows vesicles to be detected and quantified. These findings are consistent with earlier immunohistochemical observations of specific antibody binding to motor nerve terminals.

scholarly journals Differential Biophysical Properties of Infectious Intracellular and Secreted Hepatitis C Virus Particles

2006 ◽  
Vol 80 (22) ◽  
pp. 11074-11081 ◽  
Author(s):  
Pablo Gastaminza ◽  
Sharookh B. Kapadia ◽  
Francis V. Chisari
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Buoyant Density ◽  
Infection Model ◽  
Virus Particles ◽  
Viral Egress ◽  
Viral Particles ◽  
A Cell ◽  
Infected Cells

ABSTRACT The recent development of a cell culture infection model for hepatitis C virus (HCV) permits the production of infectious particles in vitro. In this report, we demonstrate that infectious particles are present both within the infected cells and in the supernatant. Kinetic analysis indicates that intracellular particles constitute precursors of the secreted infectious virus. Ultracentrifugation analyses indicate that intracellular infectious viral particles are similar in size (∼65 to 70 nm) but different in buoyant density (∼1.15 to 1.20 g/ml) from extracellular particles (∼1.03 to 1.16 g/ml). These results indicate that infectious HCV particles are assembled intracellularly and that their biochemical composition is altered during viral egress.

Determination of guanine plus cytosine content in Streptococcus pyogenes

1975 ◽  
Vol 21 (5) ◽  
pp. 722-724 ◽  
Author(s):  
James G. Stuart ◽  
Joseph J. Ferretti
Keyword(s):  
Streptococcus Pyogenes ◽  
Thermal Denaturation ◽  
Buoyant Density ◽  
Density Analysis

The guanine and cytosine content of Streptococcus pyogenes DNA was determined by thermal denaturation and buoyant density analysis to be 36.7% and 38.7%, respectively.

Mitochondrial DNA from 4-Cell Stages of Ascaris Lumbricoides

1974 ◽  
Vol 16 (3) ◽  
pp. 593-601
Author(s):  
H. TOBLER ◽  
C. GUT
Keyword(s):  
Electron Microscopy ◽  
Mitochondrial Dna ◽  
Ascaris Lumbricoides ◽  
Buoyant Density ◽  
Contour Length ◽  
Cell Stage ◽  
Replicative Intermediates ◽  
Dna Amounts

Mitochondrial DNA (mtDNA) has been isolated from 4-cell stages of Ascaris lumbricoides. This DNA amounts to about 40% of the total quantity of 4-cell-stage DNA. Its buoyant density in neutral CsCl gradients is 1.686 g cm-3. Electron microscopy of mtDNA demonstrated the presence of circular molecules with an average contour length of 4.64 µm. About 15% of these molecules are supercoiled, covalently closed circles, whereas some 2% consist of double-forked circular molecules. The form and size of these branched molecules suggest that they are replicative intermediates.

scholarly journals ISOLATION AND CHARACTERIZATION OF MITOCHONDRIAL DNA FROM DROSOPHILA MELANOGASTER

1973 ◽  
Vol 56 (2) ◽  
pp. 580-589 ◽  
Author(s):  
Mary Lake Polan ◽  
Susan Friedman ◽  
Joseph G. Gall ◽  
Walter Gehring
Keyword(s):  
Mitochondrial Dna ◽  
Drosophila Melanogaster ◽  
Average Length ◽  
Buoyant Density ◽  
Main Peak ◽  
Thermal Transitions ◽  
Isolation And Characterization ◽  
Circular Molecule ◽  
Isopycnic Centrifugation

Mitochondrial DNA (MtDNA) with a neutral buoyant density of 1.681 g/cm3 has been isolated from unfertilized eggs of Drosophila melanogaster. This DNA is a circular molecule with an average length of 5.3 µm; it reassociates with a low C0t1/2 after denaturation, and in alkaline isopycnic centrifugation it separates into strands differing in density by 0.005 g/cm3. MtDNA isolated from purified mitochondria of unfertilized eggs or from total larval DNA melts with three distinct thermal transitions. The three melting temperature values suggest that the molecule may have three regions differing in average base composition. DNA isolated from unfertilized eggs of D. melanogaster contains approximately equal amounts of MtDNA and another DNA with a buoyant density of 1.697 g/cm3, slightly less dense than main peak DNA. The possibility that the heavier DNA fraction consists of amplified ribosomal DNA was excluded by hybridization experiments, but otherwise nothing is known of its origin or function.

scholarly journals FURTHER STUDIES OF INFECTIOUS DNA EXTRACTED FROM MYCOBACTERIOPHAGES

1966 ◽  
Vol 123 (2) ◽  
pp. 327-340 ◽  
Author(s):  
Margret I. Sellers ◽  
Tohru Tokunaga
Keyword(s):  
Mycobacterium Smegmatis ◽  
Base Composition ◽  
Thermal Denaturation ◽  
Buoyant Density ◽  
Plaque Formation ◽  
Double Stranded Dna ◽  
Calf Thymus ◽  
Phage Dna ◽  
Dna Thermal Denaturation ◽  
Adenine Thymine

Results of the previous investigation in which it was found that DNA extracted from D29 mycobacteriophage was infectious for Mycobacterium smegmatis 607, have been extended. DNA extracted from mycobacteriophage D4 and D32 produced plaques when plated on their respective hosts; D28 DNA, extracted in the same manner and tested under similar conditions, failed to show infectivity. Species barriers were not crossed by mycobacteriophage DNA; bacteria resistant to intact phage were not infected with the phage DNA. The efficiency of plating of the DNA is very much lower than that of intact phage; infection of a given host was not accomplished by DNA when titration for plaque formation by the intact phage was less than 109 PFU. The base composition of DNA extracted from the four mycobacteriophages and the three propagating hosts was very similar. The bases were paired, adenine with thymine and guanine with cytosine. A relatively higher per cent of guanine-cytosine than of adenine-thymine, was found. The buoyant density of each DNA in CsCl was linearly related to its guanine-cytosine content whereas with the exception of D28 DNA, thermal denaturation temperatures failed to show this relationship. However, the thermal transition profiles were characteristic of double stranded DNA. Additional evidence that D29 DNA forms complexes with basic proteins was obtained. Binding between calf thymus histone and between RNAase and D29 DNA readily occurs with a resultant loss in DNA infectivity. Trypsin and D29 DNA are only weakly reactive.

scholarly journals Electron Microscopic Evidence for a Multimeric System of Plasmids in Fast-Growing Rhizobium Spp.

1979 ◽  
Vol 32 (6) ◽  
pp. 651 ◽  
Author(s):  
EA Schwinghamer ◽  
ES Dennis
Keyword(s):  
Size Range ◽  
Buoyant Density ◽  
Contour Length ◽  
Chromosomal Dna ◽  
Electron Microscopic ◽  
Fast Growing ◽  
Open Circular ◽  
Rhizobium Spp ◽  
Fast Growing Rhizobia ◽  
Wide Size Range

Covalently closed circular (CCC)-DNA could be isolated, by dye-buoyant density centrifugation, from l3 out of 15 strains from three species of fast-growing rhizobia. The plasmid band was also present in ineffective mutants and non-infective mutants derived from symbiotically effective, plasmid-carrying parent strains. The buoyant density in caesium chloride was 1� 719 g/cm3 for chromosomal DNA and 1� 715-1� 716 g/cm3 for plasmid DNA in the four strains examined. Electron microscopy of the CCC-DNA from five strains revealed a wide size range of large circular molecules, with the contour length ranging from l3. 5 to c. 170 jim (mol. wt range 28 x 106-352 x 106 ). Analysis of the size distribution of open circular molecules from the five strains indicated that a multimeric series of plasmid molecules may occur in these bacteria, with an estimated mean monomer length of l3�5 jlin.

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