scholarly journals A DOUBLE PRECURSOR STUDY OF NUCLEIC ACID TURNOVER IN NORMAL AND REGENERATING LIVER

1953 ◽  
Vol 202 (2) ◽  
pp. 513-520 ◽  
Author(s):  
E.P. Anderson ◽  
Stig E.G. Åqvist
1956 ◽  
Vol 46 (5) ◽  
pp. 655-667 ◽  
Author(s):  
Donald B. Cater ◽  
Barbara E. Holmes ◽  
Lorna K. Mee

1959 ◽  
Vol 37 (1) ◽  
pp. 1405-1416 ◽  
Author(s):  
J. C. Nixon ◽  
S. H. Zbarsky

A study was made of the incorporation in vivo of formate-C14 into the purines and thymine of regenerating liver and Novikoff hepatoma in the rat, during the period of maximum mitotic activity of these tissues. The effects of these tissues on one another and on certain host tissues were also studied. The maximum mitotic frequency of Novikoff hepatoma was observed on the 4th day of growth following transplantation. This tumor caused a decrease in formate incorporation into the nucleic acid purines and thymine of the host's spleen and intestinal mucosa but had little effect on liver. The results also indicated that the uptake of formate by the RNA adenine of spleen and intestinal mucosa and the DNA thymine of intestinal mucosa was diminished by the presence of regenerating liver. The simultaneous presence of both regenerating liver and Novikoff hepatoma generally lowered the incorporation of formate-C14 into the nucleic acids of the host spleen and intestinal mucosa. It was observed further that the utilization of formate by the nucleic acids of Novikoff hepatoma and regenerating rat liver was decreased in animals containing both of these rapidly dividing tissues.


1956 ◽  
Vol Original Series, Volume 46 (5) ◽  
pp. 655-667
Author(s):  
D. B. Cater ◽  
B. E. Holmes ◽  
L. K. Mee

1959 ◽  
Vol 37 (12) ◽  
pp. 1405-1416 ◽  
Author(s):  
J. C. Nixon ◽  
S. H. Zbarsky

A study was made of the incorporation in vivo of formate-C14 into the purines and thymine of regenerating liver and Novikoff hepatoma in the rat, during the period of maximum mitotic activity of these tissues. The effects of these tissues on one another and on certain host tissues were also studied. The maximum mitotic frequency of Novikoff hepatoma was observed on the 4th day of growth following transplantation. This tumor caused a decrease in formate incorporation into the nucleic acid purines and thymine of the host's spleen and intestinal mucosa but had little effect on liver. The results also indicated that the uptake of formate by the RNA adenine of spleen and intestinal mucosa and the DNA thymine of intestinal mucosa was diminished by the presence of regenerating liver. The simultaneous presence of both regenerating liver and Novikoff hepatoma generally lowered the incorporation of formate-C14 into the nucleic acids of the host spleen and intestinal mucosa. It was observed further that the utilization of formate by the nucleic acids of Novikoff hepatoma and regenerating rat liver was decreased in animals containing both of these rapidly dividing tissues.


Author(s):  
W. Bernard

In comparison to many other fields of ultrastructural research in Cell Biology, the successful exploration of genes and gene activity with the electron microscope in higher organisms is a late conquest. Nucleic acid molecules of Prokaryotes could be successfully visualized already since the early sixties, thanks to the Kleinschmidt spreading technique - and much basic information was obtained concerning the shape, length, molecular weight of viral, mitochondrial and chloroplast nucleic acid. Later, additonal methods revealed denaturation profiles, distinction between single and double strandedness and the use of heteroduplexes-led to gene mapping of relatively simple systems carried out in close connection with other methods of molecular genetics.


Author(s):  
Manfred E. Bayer

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.


Author(s):  
Dimitrij Lang

The success of the protein monolayer technique for electron microscopy of individual DNA molecules is based on the prevention of aggregation and orientation of the molecules during drying on specimen grids. DNA adsorbs first to a surface-denatured, insoluble cytochrome c monolayer which is then transferred to grids, without major distortion, by touching. Fig. 1 shows three basic procedures which, modified or not, permit the study of various important properties of nucleic acids, either in concert with other methods or exclusively:1) Molecular weights relative to DNA standards as well as number distributions of molecular weights can be obtained from contour length measurements with a sample standard deviation between 1 and 4%.


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