scholarly journals The activity of deoxyribonucleic acid polymerase and deoxyribonucleic acid synthesis in nuclei from brain fractionated by zonal centrifugation

1973 ◽  
Vol 136 (3) ◽  
pp. 685-695 ◽  
Author(s):  
M. A. Stambolova ◽  
D. Cox ◽  
A. P. Mathias
Keyword(s):  
Rat Brain ◽  
Dna Polymerase ◽  
Deoxyribonucleic Acid ◽  
Specific Radioactivity ◽  
Brain Nuclei ◽  
Neuronal Nuclei ◽  
Adult Rat ◽  
Infant Rats ◽  
Discontinuous Sucrose Gradient ◽  
Adult Rat Brain

1. The DNA polymerase (EC 2.7.7.7) activity in purified intact brain nuclei from infant rats was investigated. The effects of pH, Mg2+, glycerol, sonication and storage of the nuclei under different conditions were examined and a suitable assay system was established. 2. The nuclei from infant brain cells were fractionated by zonal centrifugation in a discontinuous sucrose gradient into five zones: zone (I) contained neuronal nuclei (59%) and astrocytic nuclei (41%); zone (II) contained astrocytic nuclei (81%) and neuronal nuclei (19%); zone (III) contained astrocytic nuclei (82%) and oligodendrocytic nuclei (18%); zone (IV) contained oligodendrocytic nuclei (92%) and zone (V) contained oligodendrocytic nuclei (100%). 3. The content of DNA, RNA and protein for each fraction was measured. 4. The distribution of DNA polymerase activity in the fractionated infant and adult rat brain nuclei was determined. The highest activity was found in the neuronal nuclei from zone (I) and the following zones exhibited a progressive decline. In contrast with the nuclei from infant rats those from adults had a much higher activity and expressed a preference for native DNA as template. 5. The deoxyribonuclease activity in all classes of nuclei was measured with [3H]DNA as substrate. A general correspondence in the pattern of the relative activities in the nuclear fractions with the distribution of DNA polymerase was found. 6. The incorporation of [3H]thymidine into nuclear DNA in infant and adult rat brain was investigated. The specific radioactivity of the DNA in the 10-day-old rats was highest in zone (V) whereas in the nuclei of adult rats, which exhibited a comparatively low incorporation, the highest specific radioactivity was associated with zones (I) and (V).

scholarly journals Accumulation and turnover of the classical Folch-Lees proteolipid proteins in developing and adult rat brain

1976 ◽  
Vol 154 (2) ◽  
pp. 265-269 ◽  
Author(s):  
H C Agrawal ◽  
K Fujimoto ◽  
R M Burton
Keyword(s):  
Rat Brain ◽  
Half Life ◽  
Specific Radioactivity ◽  
Proteolipid Protein ◽  
Total Radioactivity ◽  
Myelin Proteins ◽  
Subcutaneous Injections ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Proteolipid Proteins

The turnover of classical Folch-Lees proteolipid proteins was studied after administration of [2,3-3H]tryptophan to both developing and adult rat brain. The animals were killed from 2h to 250 days after subcutaneous injections of [3H]tryptophan. The measured specific radioactivity in developing brain attained maximum value 24h after the administration of label, whereas the total radioactivity per brain reached a maximum 21 days after injection. The half-life of proteolipid protein from the measured specific radioactivity was 7-20 days, depending on the time-points used for the calculation, whereas calculation from total radioactivity between 28-77 and 91-257 days gave half-lives of 35-40 and 188 days respectively. In contrast, in animals injected at 40 days of age, the half-life from the whole-brain-radioactivity data was 188 days. The problem of the recycling of radioactivity for the synthesis of myelin proteins from either a general or a discrete amino acid pool is discussed.

scholarly journals The synthesis of ribonucleic acid in vivo in the nuclei of rat brain fractionated by zonal centrifugation

1973 ◽  
Vol 132 (4) ◽  
pp. 813-819 ◽  
Author(s):  
J. Austoker ◽  
D. Cox ◽  
A. P. Mathias
Keyword(s):  
Rat Brain ◽  
Ribonucleic Acid ◽  
Orotic Acid ◽  
Specific Radioactivity ◽  
Brain Nuclei ◽  
Neuronal Nuclei ◽  
Intracisternal Injection ◽  
Zone Ii

1. Radioactive orotic acid, uridine and adenosine were administered to rats by intracisternal injection. The effects of the size of the dose, the specific radioactivity and time on the incorporation into the RNA of unfractionated nuclei of brain tissue were examined to establish appropriate conditions for studies of the relative activities in vivo of the various sorts of brain nuclei fractionated by zonal centrifugation. Uridine is incorporated more efficiently than either orotic acid or adenosine. 2. With [3H]uridine as precursor the astrocytes in zone (II) contain the highest radioactivity except at the beginning of the experiment when the neuronal nuclei of zone (I) are more highly labelled. This fraction utilizes [14C]orotic acid more readily than the nuclei of zone (II). The astrocytic nuclei of zone (III) show a general resemblance to those of zone (II). Considerable differences between the incorporations into the two types of oligodendrocyte nuclei in zones (IV) and (V) are observed. 3. The relative synthetic activities of the major types of brain nuclei in vitro and in vivo are discussed.

scholarly journals Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain

1976 ◽  
Vol 160 (2) ◽  
pp. 195-204 ◽  
Author(s):  
L W Hayes ◽  
F B Jungalwala
Keyword(s):  
Rat Brain ◽  
Half Life ◽  
Time Course ◽  
Specific Radioactivity ◽  
Intracerebral Injection ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Kinetics Of ◽  
Developing Rat

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.

Expression of neurocan after transient middle cerebral artery occlusion in adult rat brain

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S217-S217
Author(s):  
Kentaro Deguchi ◽  
Mikiro Takaishi ◽  
Takeshi Hayashi ◽  
Atsuhiko Oohira ◽  
Shoko Nagotani ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Rat Brain ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Artery Occlusion ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Cerebral Artery Occlusion
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