scholarly journals Occurrence of Petunia Vein-Clearing Virus in the U.S.A.

Plant Disease ◽  
1998 ◽  
Vol 82 (2) ◽  
pp. 262-262 ◽  
Author(s):  
B. E. L. Lockhart ◽  
D.-E. Lesemann
Keyword(s):  
Petunia Hybrida ◽  
Virus Isolate ◽  
Leaf Size ◽  
Uranyl Acetate ◽  
Spherical Particles ◽  
Serological Relationship ◽  
Vein Clearing ◽  
Double Stranded Dna ◽  
Tentative Member ◽  
Favorable Conditions

Petunia vein-clearing virus (PVCV), a tentative member of the caulimovirus group of plant pararetroviruses, was first identified in petunia (Petunia hybrida Vilm.) in Germany in the hybrid cv. Himmelröschen (1). A similar virus was recently identified in Minnesota in the petunia cv. Fantasy Pink grown from seed in commercial greenhouses. This virus has spherical particles 46 to 47 nm in diameter in preparations negatively stained with 1% uranyl acetate or sodium phosphotungstate, pH 7.0, and which contain a double-stranded DNA genome approximately 7.3 kb in size. The virus was shown by immunoelectron microscopy (IEM) to be closely related serologically to PVCV. No serological relationship to any other caulimoviruses was detected. Like PVCV, which is transmitted only by seed and grafting, the Minnesota virus isolate was not transmitted by mechanical inoculation to petunia or any other indicator plant. Symptoms associated with infection by PVCV in cv. Fantasy Pink consisted of mild vein clearing to severe vein yellowing, and reduction in leaf size and internode length. Symptoms were most frequently expressed when plants were under water and nutrient stress. Vigorously growing plants usually showed no symptoms, and no virions were detected by IEM in partially purified extracts from such plants. This suggests that infection of petunia hybrids by seed-borne PVCV may possibly be more widespread, but may go unnoticed because virus-induced symptoms may not be elicited in plants growing under favorable conditions. References: (1) D. Lesemann and R. Casper. Phytopathology 63:1118, 1973.

Morphogenesis of a New Human Herpes-Type Virus Isolate (Sasha Virus)

1973 ◽  
Vol 31 ◽  
pp. 592-593
Author(s):  
R. F. Zeigel ◽  
W. Munyon
Keyword(s):  
Virus Isolate ◽  
Calf Serum ◽  
Uranyl Acetate ◽  
Human Herpes ◽  
Human Embryonic Lung ◽  
Human Herpes Virus ◽  
Intracytoplasmic Inclusions ◽  
Hel Cells ◽  
And Control

In continuing studies on the role of viruses in biochemical transformation, Dr. Munyon has succeeded in isolating a highly infectious human herpes virus. Fluids of buccal pustular lesions from Sasha Munyon (10 mo. old) uiere introduced into monolayer sheets of human embryonic lung (HEL) cell cultures propagated in Eagles’ medium containing 5% calf serum. After 18 hours the cells exhibited a dramatic C.P.E. (intranuclear vacuoles, peripheral patching of chromatin, intracytoplasmic inclusions). Control HEL cells failed to reflect similar changes. Infected and control HEL cells were scraped from plastic flasks at 18 hrs. of incubation and centrifuged at 1200 × g for 15 min. Resultant cell packs uiere fixed in Dalton's chrome osmium, and post-fixed in aqueous uranyl acetate. Figure 1 illustrates typical hexagonal herpes-type nucleocapsids within the intranuclear virogenic regions. The nucleocapsids are approximately 100 nm in diameter. Nuclear membrane “translocation” (budding) uias observed.

Synchrony of Digestion of SV40 DNA by Exonuclease III Determined by EM

1975 ◽  
Vol 33 ◽  
pp. 674-675
Author(s):  
Ray Wu ◽  
G. Ruben ◽  
B. Siegel ◽  
P. Spielman ◽  
E. Jay
Keyword(s):  
Dark Field ◽  
Uranyl Acetate ◽  
Enzyme Digestion ◽  
Dna Molecules ◽  
Exonuclease Iii ◽  
Aluminum Films ◽  
Double Stranded Dna ◽  
Before And After ◽  
Exo Iii ◽  
Sv40 Dna

A method for determining long nucleotide sequences of double-stranded DNA is being developed. It involves (a) the synchronous digestion of the DNA from the 3' ends with EL coli exonuclease III (Exo III) followed by (b) resynthesis with labeled nucleotides and DNA polymerase. A crucial factor in the success of this method is the degree to which the enzyme digestion proceeds synchronously under proper conditions of incubation (step a). Dark field EM is used to obtain accurate measurements on the lengths and distribution of the DNA molecules before and after digestion with Exo III, while gel electrophoresis is used in parallel to obtain a mean length for these molecules. It is the measurements on a large enough sample of individual molecules by EM that provides the information on how synchronously the digestion proceeds. For length measurements, the DNA molecules were picked up on 20-30 Å thick carbon-aluminum films, using the aqueous Kleinschmidt technique and stained with 7.5 x 10-5M uranyl acetate in 90% ethanol for 3 minutes.

Motion Picture Study of Balata and Hevea Latices. With Observations on Buna-S and Neoprene Latices

1943 ◽  
Vol 16 (3) ◽  
pp. 509-528
Author(s):  
Francis F. Lucas
Keyword(s):  
Large Particle ◽  
Spherical Particles ◽  
Dispersed Particles ◽  
Shaped Particle ◽  
Merging Process ◽  
Common Unit ◽  
Large Spherical Particle ◽  
Mathematical Analyses ◽  
Favorable Conditions ◽  
State Of Tension

Abstract In dispersions of Hevea or balata latex, motion of the particles appears to be controlled by forces acting between particles. The particles are known to have negative charges. It is believed that these charges may not be uniformly distributed over the surface of the particles, and that they fluctuate in intensity. The charges tend to keep the particles separated. Under normal conditions of motion there is no evidence that the particles collide. They approach and recede from one another. Particles differing in size are found associated. A common unit is the doublet, composed of a large particle and an associated small particle acting as a satellite. Particles of varying size seem to have a tendency to form a group or constellation. The motions of a constellation appear to be centered about the largest particle. This particle may have several satellites. Each satellite may have one or more satellites. A large particle is never seen to gyrate about a smaller particle. If the negative charges are nullified, agglomeration takes place. There seems to be some force acting in opposition to that of electrical repulsion. Isolated single particles or units (doublets, triplets, and quads) seem to manifest very little motion. As the concentration of the dispersed particles is increased, the motions appear to be greatly increased. Mathematical analyses based on measurements of the films should provide data which will determine whether this assumption is valid. In dilute dispersions, particle relations can be readily demonstrated, and the particles seem to assume a state of colloidal equilibrium. It appears that the particles were mutually in a state of tension. Motions are slight. Rather concentrated dispersions form chains, groups, and dark interspaces or “holes”. No evidence has been deduced that magnetism plays any part in this grouping arrangement. It is believed that the phenomenon may be fully accounted for on the basis that it is the resultant of forces acting between particles. Time studies show that merging of particles occurs. A simple case may be described as two spherical particles, one larger than the other, in doublet arrangement. The smaller particle may lose its charge, or through some other cause is attracted by the larger particle to which it becomes attached. Through the action of other forces, it appears to be pulled into the larger particle, resulting in an irregularly shaped particle. Ultimately, under favorable conditions, the larger particle completely absorbs the smaller particle and then becomes spherical. During the merging process, however, other particles may be attracted and become attached to this irregular-shaped particle. A common arrangement seems to be a tapering chain of particles, consisting of a large bulbous particle at one end to which have become attached several particles, each succeeding particle somewhat smaller in diameter than its neighbor. In process of merging, these particles are gradually pulled into the large bulbous particle, which ultimately may become a large spherical particle.

scholarly journals Characterization of Swine Infertility and Respiratory Syndrome (SIRS) Virus (Isolate ATCC VR-2332)

1992 ◽  
Vol 4 (2) ◽  
pp. 127-133 ◽  
Author(s):  
David A. Benfield ◽  
Eric Nelson ◽  
James E. Collins ◽  
Lou Harris ◽  
Sagar M. Goyal ◽  
...  
Keyword(s):  
Virus Isolate ◽  
Rna Virus ◽  
Cesium Chloride ◽  
Average Diameter ◽  
Lactic Dehydrogenase ◽  
Spherical Particles ◽  
Laboratory Studies ◽  
The Family ◽  
Nm Range

The characterization of an isolate of swine infertility and respiratory syndrome (SIRS) virus (ATCC VR-2332) is reported. A commercial cell line (CL262 1) was used for the propagation of the virus for all assays. Laboratory studies indicate that this isolate is a fastidious, nonhemagglutinating, enveloped RNA virus. Cesium chloride-purified virions visualized by electron microscopy were spherical particles with an average diameter of 62 nm (range: 48–83 nm) and a 25–30 nm core surrounded by an envelope. Virus replication was restricted to the cytoplasm, as demonstrated by immunofluorescence. The virus did not react serologically with antisera to several common porcine viruses or with antisera to known viruses in the alphavirus, rubivirus, pestivirus, and ungrouped lactic dehydrogenase virus genera of the Togaviridae. However, convalescent sow sera and rabbit hyperimmune sera neutralized the SIRS virus at titers of 1:256 and 1:512, respectively. The virus was stable at 4 and −70 C, but was labile at 37 and 56 C. The properties of this isolate of SIRS virus resemble those of the family Togaviridae but do not match the described genera.

Mars: was There an Ancient Eden?

1997 ◽  
Vol 161 ◽  
pp. 203-218 ◽  
Author(s):  
Tobias C. Owen
Keyword(s):  
Positive Answer ◽  
Biogenic Elements ◽  
Habitable Zones ◽  
The Face ◽  
The Origin Of Life ◽  
Early Mars ◽  
Favorable Conditions ◽  
Open Question ◽  
Rocky Planets ◽  
Impact Erosion

AbstractThe clear evidence of water erosion on the surface of Mars suggests an early climate much more clement than the present one. Using a model for the origin of inner planet atmospheres by icy planetesimal impact, it is possible to reconstruct the original volatile inventory on Mars, starting from the thin atmosphere we observe today. Evidence for cometary impact can be found in the present abundances and isotope ratios of gases in the atmosphere and in SNC meteorites. If we invoke impact erosion to account for the present excess of129Xe, we predict an early inventory equivalent to at least 7.5 bars of CO2. This reservoir of volatiles is adequate to produce a substantial greenhouse effect, provided there is some small addition of SO2(volcanoes) or reduced gases (cometary impact). Thus it seems likely that conditions on early Mars were suitable for the origin of life – biogenic elements and liquid water were present at favorable conditions of pressure and temperature. Whether life began on Mars remains an open question, receiving hints of a positive answer from recent work on one of the Martian meteorites. The implications for habitable zones around other stars include the need to have rocky planets with sufficient mass to preserve atmospheres in the face of intensive early bombardment.

Platinum Compounds as Stains for Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 230-231
Author(s):  
S. K. Aggarwal ◽  
P. McAllister ◽  
R. W. Wagner ◽  
B. Rosenberg
Keyword(s):  
Electron Microscopy ◽  
Hela Cells ◽  
Uranyl Acetate ◽  
Sarcoma 180 ◽  
Platinum Compounds ◽  
Kb Cells ◽  
En Bloc ◽  
Human Lymphoma ◽  
Ultrathin Sections ◽  
Blue Coloration

Uranyl acetate has been used as an electron stain for en bloc staining as well as for staining ultrathin sections in conjunction with various lead stains (Fig. 1). Present studies reveal that various platinum compounds also show promise as electron stains. Certain platinum compounds have been shown to be effective anti-tumor agents. Of particular interest are the compounds with either uracil or thymine as one of the ligands (cis-Pt(II)-uracil; cis-Pt(II)-thymine). These compounds are amorphous, highly soluble in water and often exhibit an intense blue coloration. These compounds show enough electron density to be used as stains for electron microscopy. Most of the studies are based on various cell lines (human AV, cells, human lymphoma cells, KB cells, Sarcoma-180 ascites cells, chick fibroblasts and HeLa cells) while studies on tissue blocks are in progress.

Ultrastructure of Some Planktonic Formainifera

1974 ◽  
Vol 32 ◽  
pp. 190-191
Author(s):  
William H. Zucker
Keyword(s):  
Cell Biology ◽  
Water Mass ◽  
Planktonic Foraminifera ◽  
Uranyl Acetate ◽  
Ethanol Dehydration ◽  
Globigerinoides Ruber ◽  
Light Microscope Level ◽  
Globigerina Bulloides ◽  
Glutaraldehyde Solution ◽  
Diamond Knife

Planktonic foraminifera are widely-distributed and abundant zooplankters. They are significant as water mass indicators and provide evidence of paleotemperatures and events which occurred during Pleistocene glaciation. In spite of their ecological and paleological significance, little is known of their cell biology. There are few cytological studies of these organisms at the light microscope level and some recent reports of their ultrastructure.Specimens of Globigerinoides ruber, Globigerina bulloides, Globigerinoides conglobatus and Globigerinita glutinata were collected in Bermuda waters and fixed in a cold cacodylate-buffered 6% glutaraldehyde solution for two hours. They were then rinsed, post-fixed in Palade's fluid, rinsed again and stained with uranyl acetate. This was followed by graded ethanol dehydration, during which they were identified and picked clean of debris. The specimens were finally embedded in Epon 812 by placing each organism in a separate BEEM capsule. After sectioning with a diamond knife, stained sections were viewed in a Philips 200 electron microscope.

Cellular Contacts Within the Interhemal Membrane of the Rat Placenta at Term

1974 ◽  
Vol 32 ◽  
pp. 146-147
Author(s):  
William P. Jollie
Keyword(s):  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Capillary Endothelium ◽  
En Bloc ◽  
Aldehyde Fixation ◽  
Chorioallantoic Placenta

By routine EM preparative techniques, the tissues which, collectively, separate maternal and fetal bloods in the fully formed chorioallantoic placenta of the rat have been shown to consist of three chorionic layers, or trophoblast, and a layer of allantoic capillary endothelium [Fig. 1]. Relationships between these layers are best demonstrated by special techniques, viz., cacodylate-buffered aldehyde fixation, collidine-buffered osmium tetroxide postfixation, and en bloc staining with uranyl acetate. By using this method on placentas at term, the cells of the outermost chorionic layer (Trophoblast 1) appear to be attached to each other by means of maculae adherentes which sometimes occur in clusters [Fig. 2].

Ca-Histochemistry in slime mold plasmodia

1978 ◽  
Vol 36 (2) ◽  
pp. 130-131
Author(s):  
Ulrich Dierkes
Keyword(s):  
Physarum Polycephalum ◽  
Carbon Coating ◽  
Freeze Drying ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Slime Mold ◽  
Staining Procedure ◽  
Protoplasmic Streaming ◽  
Intracellular Ca

Calcium is supposed to play an important role in the control of protoplasmic streaming in slime mold plasmodia. The motive force for protoplasmic streaming is generated by the interaction of actin and myosin. This contraction is supposed to be controlled by intracellular Ca-fluxes similar to the triggering system in skeleton muscle. The histochemical localisation of calcium however is problematic because of the possible diffusion artifacts especially in aquous media.To evaluate this problem calcium localisation was studied in small pieces of shock frozen (liquid propane at -189°C) plasmodial strands of Physarum polycephalum, which were further processed with 3 different methods: 1) freeze substitution in ethanol at -75°C, staining in 100% ethanol with 1% uranyl acetate, and embedding in styrene-methacrylate. For comparison the staining procedure was omitted in some preparations. 2)Freeze drying at about -95°C, followed by immersion with 100% ethanol containing 1% uranyl acetate, and embedding. 3) Freeze fracture, carbon coating and SEM investigation at temperatures below -100° C.

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