Biomaterial Database

Morphology of a virus of blue-green algae and properties of its deoxyribonucleic acid. 1967

R Luftig, and R Haselkorn

The morphology of Safferman's virus of blue-green algae (phycovirus LPP-1) has been studied by electron microscopy and physicochemical methods. The virion has a short (100 to 200 A long, 150 A in diameter) forked tail, with an outer sheath, an inner core, and a capital attached to one of the vertices of a polyhedral head. The head capsid edge-to-edge distance is 600 A, based upon internal calibration of the magnification in electron micrographs by use of the line-line spacing of catalase crystals. Measurements of absorbancy and infectivity, and electron microscopy across the band of virus after zone centrifugation on a sucrose gradient, indicated that infectivity was correlated with the short-tailed particles described. The viral deoxyribonucleic acid (DNA) is linear, with a contour length of 13.2 +/- 0.5 mu, measured by the Kleinschmidt method. Its sedimentation coefficient, S(0) (20, w), is 33.4 +/- 0.7 S. These values are consistent with a molecular weight of 27 x 10(6) for the viral DNA. Based upon buoyant density in CsCl and thermal denaturation, the guanine-cytosine content of the DNA is 53%. The viral DNA was used as template for in vitro ribonucleic acid (RNA) synthesis by Escherichia coli RNA polymerase. This RNA annealed to 18% of the sequences in the viral DNA, 0.5% of the sequences in bacteriophage T7 DNA, and 0.25% of the sequences in Plectonema boryanum DNA, at saturating levels of RNA in the Hall-Nygaard hybridization assay. The lack of homology with T7 DNA is of interest because the two viruses are very similar morphologically. The lack of homology with host DNA suggests that this algal virus is a poor candidate for transduction.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010942	Plant Viruses	Viruses parasitic on plants.	Phytophagineae,Plant Virus,Virus, Plant,Viruses, Plant
D002374	Catalase	An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.	Catalase A,Catalase T,Manganese Catalase,Mn Catalase
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D003596	Cytosine	A pyrimidine base that is a fundamental unit of nucleic acids.
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D006147	Guanine
D006462	Hemolytic Plaque Technique	A method to identify and enumerate cells that are synthesizing ANTIBODIES against ANTIGENS or HAPTENS conjugated to sheep RED BLOOD CELLS. The sheep red blood cells surrounding cells secreting antibody are lysed by added COMPLEMENT producing a clear zone of HEMOLYSIS. (From Illustrated Dictionary of Immunology, 3rd ed)	Jerne's Plaque Technique,Hemolytic Plaque Technic,Jerne's Plaque Technic,Hemolytic Plaque Technics,Hemolytic Plaque Techniques,Jerne Plaque Technic,Jerne Plaque Technique,Jernes Plaque Technic,Jernes Plaque Technique,Plaque Technic, Hemolytic,Plaque Technic, Jerne's,Plaque Technics, Hemolytic,Plaque Technique, Hemolytic,Plaque Technique, Jerne's,Plaque Techniques, Hemolytic,Technic, Hemolytic Plaque,Technic, Jerne's Plaque,Technics, Hemolytic Plaque,Technique, Hemolytic Plaque,Technique, Jerne's Plaque,Techniques, Hemolytic Plaque
D006824	Hybridization, Genetic	The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid.	Crossbreeding,Hybridization, Intraspecies,Crossbreedings,Genetic Hybridization,Genetic Hybridizations,Hybridizations, Genetic,Hybridizations, Intraspecies,Intraspecies Hybridization,Intraspecies Hybridizations