Deoxyribonucleic acid synthesis and deoxyribonucleic acid-polymerase activity during early germination of wheat embryos at high and low viability

1980 ◽  
Vol 22 (4) ◽  
pp. 287-293 ◽  
Author(s):  
A. Dell’Aquila ◽  
Lucia Lioi ◽  
I. Scarascia
Keyword(s):  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Polymerase Activity ◽  
Deoxyribonucleic Acid Synthesis ◽  
Early Germination ◽  
Wheat Embryos

Elevated levels of (2'-5')oligoadenylic acid polymerase activity in growth-arrested human lymphoblastoid Namalva cells

1981 ◽  
Vol 1 (10) ◽  
pp. 932-938
Author(s):  
I Krishnan ◽  
C Baglioni
Keyword(s):  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Polymerase Activity ◽  
S Phase ◽  
Activity Level ◽  
Fresh Medium ◽  
Growth Status ◽  
Enzyme Degradation ◽  
Deoxyribonucleic Acid Synthesis ◽  
In Cells

(2'-5')Oligoadenylic acid [(2'-5')An] polymerase activity was measured in extracts of human lymphoblastoid cells of the Namalva line cultured under different conditions. Exponentially growing cells had a relatively low polymerase activity level, whereas cells grown to limit density showed elevated levels. When fresh medium was added to growth-arrested cells, (2'-5')An polymerase activity decreased concomitantly with the initiation of active deoxyribonucleic acid synthesis. An increase in polymerase activity level was also observed after exponentially growing cells were transferred from medium containing 20% serum to fresh medium containing 0.2% serum. These cells diminished deoxyribonucleic acid synthesis and remained quiescent until 20% serum was again added. Polymerase activity level decreased as the cells entered into S phase. The addition of the inhibitor of deoxyribonucleic acid synthesis, hydroxyurea, to exponentially growing cells did not increase polymerase level, indicating that cells blocked in S phase and at the G1-S boundary maintained the basal level of this enzyme. Degradation of labeled (2'-5')An was measured in extracts of Namalva cells cultured under different conditions, but no significant differences among degradative activities were observed. Since (2'-5')An polymerase activity is one of the enzymatic activities induced by interferon, we measured interferon titers in Namalva cell medium. Less than 1 reference unit per ml was detected in cells grown under different conditions. Moreover, the increase in (2'-5')An polymerase activity level in cells transferred from 20 to 0.2% serum was not prevented by including anti-lymphoblastoid interferon antibody in the medium. These results suggest that the activity level of (2'-5')An polymerase is regulated in Namalva cells on the basis of the growth status of the cells and that this regulatory mechanism is apparently not activated by interferon.

scholarly journals Elevated levels of (2'-5')oligoadenylic acid polymerase activity in growth-arrested human lymphoblastoid Namalva cells.

1981 ◽  
Vol 1 (10) ◽  
pp. 932-938 ◽  
Author(s):  
I Krishnan ◽  
C Baglioni
Keyword(s):  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Polymerase Activity ◽  
S Phase ◽  
Activity Level ◽  
Fresh Medium ◽  
Growth Status ◽  
Enzyme Degradation ◽  
Deoxyribonucleic Acid Synthesis ◽  
In Cells

(2'-5')Oligoadenylic acid [(2'-5')An] polymerase activity was measured in extracts of human lymphoblastoid cells of the Namalva line cultured under different conditions. Exponentially growing cells had a relatively low polymerase activity level, whereas cells grown to limit density showed elevated levels. When fresh medium was added to growth-arrested cells, (2'-5')An polymerase activity decreased concomitantly with the initiation of active deoxyribonucleic acid synthesis. An increase in polymerase activity level was also observed after exponentially growing cells were transferred from medium containing 20% serum to fresh medium containing 0.2% serum. These cells diminished deoxyribonucleic acid synthesis and remained quiescent until 20% serum was again added. Polymerase activity level decreased as the cells entered into S phase. The addition of the inhibitor of deoxyribonucleic acid synthesis, hydroxyurea, to exponentially growing cells did not increase polymerase level, indicating that cells blocked in S phase and at the G1-S boundary maintained the basal level of this enzyme. Degradation of labeled (2'-5')An was measured in extracts of Namalva cells cultured under different conditions, but no significant differences among degradative activities were observed. Since (2'-5')An polymerase activity is one of the enzymatic activities induced by interferon, we measured interferon titers in Namalva cell medium. Less than 1 reference unit per ml was detected in cells grown under different conditions. Moreover, the increase in (2'-5')An polymerase activity level in cells transferred from 20 to 0.2% serum was not prevented by including anti-lymphoblastoid interferon antibody in the medium. These results suggest that the activity level of (2'-5')An polymerase is regulated in Namalva cells on the basis of the growth status of the cells and that this regulatory mechanism is apparently not activated by interferon.

scholarly journals Onset of Deoxyribonucleic Acid Synthesis in Germinating Wheat Embryos

1972 ◽  
Vol 49 (1) ◽  
pp. 20-23 ◽  
Author(s):  
Yves Y. Mory ◽  
David Chen ◽  
Sara Sarid
Keyword(s):  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Deoxyribonucleic Acid Synthesis ◽  
Wheat Embryos

scholarly journals Factors affecting the onset of deoxyribonucleic acid synthesis during wheat embryo germination. Study of the changes in DNA polymerases A, B and C and the pool of DNA precursors

1979 ◽  
Vol 181 (1) ◽  
pp. 193-199 ◽  
Author(s):  
M Castroviejo ◽  
D Tharaud ◽  
B Mocquot ◽  
S Litvak
Keyword(s):  
Deoxyribonucleic Acid ◽  
Dna Polymerases ◽  
Acid Synthesis ◽  
Antigenic Relationship ◽  
Embryo Germination ◽  
Wheat Embryo ◽  
Factors Affecting ◽  
Water Imbibition ◽  
Deoxyribonucleic Acid Synthesis ◽  
Wheat Embryos

DNA synthesis starts about 12 h after water imbibition in wheat embryos. We have determined that noticeable amounts of labelled thymidine are found inside the embryo only after 6 hr of germination. DNA polymerase C from ungerminated wheat embryos decreased markedly in activity during the first hours of germination, whereas the activities of DNA polymerases A and B increased, having a maximum at about 15 h or germination. Serological evidence has suggested a clear antigenic relationship between DNA polymerases A and C. Although the pool of ATP increases rapidly after water imbibition, the increase in the pool of dNTP species was much slower.

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