Tissue nucleic acid concentrations

II. Influence of Vitamin E Deficiency on Tissue Nucleic Acid Concentrations. 512... 

Our own experiments, which were started approximately ten years ago, have utilized rats, rabbits, and monkeys, and we have investigated the influence of vitamin E deficiency on tissue nucleic acid concentrations in... 

The data in Table I summarize some of the findings on the influence of vitamin E deficiency on tissue nucleic acid concentrations. In the monkey and rabbit, vitamin E deficiency results in a great increase in the concentration of DNA per gram wet weight of skeletal muscle. This is in agreement with the histologic picture of these tissues, which is characterized by an increase in number of sarcolerama nuclei. Also in the monkey there is a considerable increase in the concentration of DNA and RNA in bone marrow. 

Nucleic acid concentrations are expressed as mtlligranis nudeic add P per gram wet weight of tissue. 

Zinc. The 2—3 g of zinc in the human body are widely distributed in every tissue and tissue duid (90—92). About 90 wt % is in muscle and bone unusually high concentrations are in the choroid of the eye and in the prostate gland (93). Almost all of the zinc in the blood is associated with carbonic anhydrase in the erythrocytes (94). Zinc is concentrated in nucleic acids (90), and found in the nuclear, mitochondrial, and supernatant fractions of all cells. 

The presence of nucleic acids ia yeast is oae of the maia problems with their use ia human foods. Other animals metabolize uric acid to aHantoia, which is excreted ia the uriae. Purines iagested by humans and some other primates are metabolized to uric acid, which may precipitate out ia tissue to cause gout (37). The daily human diet should contain no more than about 2 g of nucleic acid, which limits yeast iatake to a maximum of 20 g. Thus, the use of higher concentrations of yeast proteia ia human food requires removal of the nucleic acids. Unfortunately, yields of proteia from extracts treated as described are low, and the cost of the proteia may more than double. 

Commercial use of cell and tissue culture continues to expand. Improvement of organisms through recombinant nucleic acid techniques has become commonplace. Formerly, a few laboratories were well ahead of most others, but now the methods have been perfected for routine use. Another technique that is widely practiced is culturing of cells that excrete high concentrations of just one antibody protein. The specificity of antibodies and antigens is exploited in medical testing procedures using these pure monoclonal antibodies. 

Classical approaches to plant DNA isolation aim to produce large quantities of highly purified DNA. However, smaller quantities of crudely extracted plant DNA are often acceptable for PCR analysis. Another efficient method for preparation of plant DNA for PCR is a single-step protocol that involves heating a small amount of plant tissue in a simple solution. Several factors influence nucleic acid release from tissue salt, EDTA, pH, incubation time and temperature. These factors must be optimized for different sample substrates. EDTA in the sample solution binds the Mg + cofactor required by the Taq polymerase in the PCR, so the EDTA concentration in the solution, or the Mg + concentration in the PCR, must be carefully optimized. 

Before starting experiments with human or animal tissue samples, it is extremely important to optimize in vitro experimental conditions. With a purified template nucleic acid, standardize RT and PCR conditions. Check the specificity and crossreactivity of primers and probes. Sometimes it is necessary to alter MgCl2 concentration under in situ reaction conditions. The blocking reagent for filter hybridization could be different than the in situ protocol. (I use 1 % purified casein solution for filter hybridization and 3% BSA for in situ signal detection.)... 

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