Determination of Base Sequence in Nucleic Acids with the Electron Microscope. V. The Thymine-Specific Reactions of Osmium Tetroxide with Deoxyribonucleic Acid and Its Components*

Biochemistry ◽  
1966 ◽  
Vol 5 (7) ◽  
pp. 2283-2288 ◽  
Author(s):  
Michael Beer ◽  
Samuel Stern ◽  
Duane Carmalt ◽  
Kenneth H. Mohlhenrich
Keyword(s):  
Electron Microscope ◽  
Nucleic Acids ◽  
Osmium Tetroxide ◽  
Deoxyribonucleic Acid ◽  
Base Sequence ◽  
Specific Reactions

THE CONCENTRATION OF NUCLEIC ACIDS IN SOME COMMON MARINE ALGAE

1964 ◽  
Vol 42 (11) ◽  
pp. 1471-1480 ◽  
Author(s):  
E. Gordon Young
Keyword(s):  
Nucleic Acids ◽  
Ribonucleic Acid ◽  
Marine Algae ◽  
Deoxyribonucleic Acid ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Fucus Vesiculosus ◽  
Chondrus Crispus ◽  
Rna And Dna

The method of Smillie and Krotkov has been applied to the estimation of soluble ribonucleic acid and deoxyribonucleic acid in nine species of marine algae, representative of the Chlorophyceae, Rhodophyceae, and Phaeophyceae. Treatment of the extract with an anion exchange resin was essential for the determination of RNA. Values for RNA and DNA, expressed as percentages of total solids, were respectively as follows: Ulva lactuca 0.63 and 0.10, Chondrus crispus 0.91 and 0.65, Rhodymenia palmata 0.73 and 0.41, Porphyra umbilicalis 1.62 and 0.19, Furcellaria fastigiata 0.37 and 0.36, Laminaria longicruris 0.68 and 0.06, L. digitata 0.67 and 0.30, L. agardhii 0.90 and 0.07, Fucus vesiculosus 0.29 and 0.05, based on commercial nucleic acids assayed by ultraviolet absorption, as standards. Use of ribose and deoxyribose as standards gave lower results. Attempts to prepare pure polynucleotides from several marine algae were unsuccessful.

Electron Microscopic Studies of Labeled Nucleic Acids

1976 ◽  
Vol 34 ◽  
pp. 328-329
Author(s):  
M. D. Cole ◽  
S. D. Rose ◽  
J. W. Wiggins ◽  
M. Beer
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Nucleic Acids ◽  
Osmium Tetroxide ◽  
Signal To Noise Ratio ◽  
Scattered Intensity ◽  
Signal To Noise ◽  
Electron Microscopic ◽  
Modified Nucleic Acids ◽  
Microscopic Studies

Quantitative conversion of cytosine nucleotides to N4-furfuryloxy derivatives followed by reaction with osmium tetroxide plus bipyridine yields an electrondense stain suitable for visualization in the electron microscope. Chemical analysis shows that two osmium atoms become attached to each furan-modified cytosine nucleotide. Osmium tetroxide also reacts with thymine and uracil nucleotides, resulting in the attachment of one osmium atom each. Therefore the treatment of cytosine-modified nucleic acids with osmium tetroxide should allow recognition of cytosine and thymine nucleotides.Nucleic acids labeled with osmium by the above reactions have been viewed in a high resolution STEM. The signal used to form the image is the ratio of the elastically scattered intensity to the unscattered and ineiastically scattered intensity. The dosage that yields a signal to noise ratio sufficient for focussing is >104 electrons/ Å2.

scholarly journals Ultrastructure of microfilament bundles in baby hamster kidney (BHK-21) cells. The use of tannic acid.

1979 ◽  
Vol 80 (3) ◽  
pp. 759-766 ◽  
Author(s):  
R D Goldman ◽  
B Chojnacki ◽  
M J Yerna
Keyword(s):  
Electron Microscope ◽  
Electron Density ◽  
Tannic Acid ◽  
Osmium Tetroxide ◽  
Stress Fibers ◽  
Supramolecular Organization ◽  
Glutaraldehyde Fixation ◽  
Microfilament Bundles ◽  
Electron Density Shifts

After standard glutaraldehyde-osmium tetroxide fixation procedures, the majority of microfilament bundles in BHK-21 cells exhibit relatively uniform electron density along their long axes. The inclusion of tannic acid in the glutaraldehyde fixation solution results in obvious electron density shifts along the majority of microfilament bundles. Striated patterens are frequently observed which consist of regularly spaced electron dense (D) and electron lucid (L) bands. A striated pattern is also observed along many BHK-21 stress fibers after processing for indirect immunofluorescence utilizing BHK-21 myosin antiserum. A direct correlation of these periodicities seen by light and electron microscope techniques is impossible at the present time. However, comparative measurements indicate that the overall patterns seen in the immunofluorescence and electron microscope preparations are similar. The ultrastructural results provide an initial clue for the ultimate determination of the supramolecular organization of contracile proteins other than actin within the microfilament bundles of non-muscle cells.

Further Observations on the Virus of Epizootic Diarrhea of Infant Mice. An Electron Microscopic Study

1967 ◽  
Vol 25 ◽  
pp. 110-111
Author(s):  
W. G. Banfield ◽  
G. Kasnic ◽  
J. H. Blackwell
Keyword(s):  
Electron Microscope ◽  
Infected Cell ◽  
Microscopic Study ◽  
Intestinal Epithelium ◽  
Ultrastructural Study ◽  
Osmium Tetroxide ◽  
Lead Citrate ◽  
Electron Microscopic ◽  
Virus Particles ◽  
Infected Cells

An ultrastructural study of the intestinal epithelium of mice infected with the agent of epizootic diarrhea of infant mice (EDIM virus) was first performed by Adams and Kraft. We have extended their observations and have found developmental forms of the virus and associated structures not reported by them.Three-day-old NLM strain mice were infected with EDIM virus and killed 48 to 168 hours later. Specimens of bowel were fixed in glutaraldehyde, post fixed in osmium tetroxide and embedded in epon. Sections were stained with uranyl magnesium acetate followed by lead citrate and examined in an updated RCA EMU-3F electron microscope.The cells containing virus particles (infected) are at the tips of the villi and occur throughout the intestine from duodenum through colon. All developmental forms of the virus are present from 48 to 168 hours after infection. Figure 1 is of cells without virus particles and figure 2 is of an infected cell. The nucleus and cytoplasm of the infected cells appear clearer than the cells without virus particles.

Ultrastructural comparison of prolactin adenomas of pituitary in men and women

1988 ◽  
Vol 46 ◽  
pp. 346-347
Author(s):  
R.C. Caughey ◽  
U.P. Kalyan-Raman
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Phosphate Buffer ◽  
Pituitary Adenomas ◽  
Osmium Tetroxide ◽  
Secretory Granules ◽  
Uranyl Acetate ◽  
En Bloc ◽  
Men And Women ◽  
Transmission Electron

Prolactin producing pituitary adenomas are ultrastructurally characterized by secretory granules varying in size (150-300nm), abundance of endoplasmic reticulum, and misplaced exocytosis. They are also subclassified as sparsely or densely granulated according to the amount of granules present. The hormone levels in men and women vary, being higher in men; so also the symptoms vary between both sexes. In order to understand this variation, we studied 21 prolactin producing pituitary adenomas by transmission electron microscope. This was out of a total of 80 pituitary adenomas. There were 6 men and 15 women in this group of 21 prolactinomas.All of the pituitary adenomas were fixed in 2.5% glutaraldehyde, rinsed in Millonig's phosphate buffer, and post fixed with 1% osmium tetroxide. They were then en bloc stained with 0.5% uranyl acetate, rinsed with Walpole's non-phosphate buffer, dehydrated with graded series of ethanols and embedded with Epon 812 epoxy resin.

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