Natural and artificial seed ageing in maize: germination and DNA synthesis

1993 ◽  
Vol 3 (4) ◽  
pp. 279-285 ◽  
Author(s):  
Germán Gutiérrez ◽  
Felipe Cruz ◽  
Juan Moreno ◽  
Victor A. González-Hernández ◽  
Jorge M. Vázquez-Ramos
Keyword(s):  
Dna Synthesis ◽  
Critical Factor ◽  
Polymerase Activity ◽  
Genetic Constitution ◽  
Dry Matter Accumulation ◽  
Seed Deterioration ◽  
Maize Genotypes ◽  
Artificial Seed ◽  
Seed Ageing ◽  
Physiological And Biochemical

AbstractThe effect of natural and artificial seed ageing has been compared in terms of physiological and biochemical responses of several maize genotypes. The physiological parameters were: viability, germinability, emergence in sand and dry matter accumulation. The biochemical parameters were: DNA synthesis and DNA polymerase activity. A close and direct relationship was found between seed deterioration and DNA metabolism in all maize materials which responded to ageing according to their genetic constitution; i.e., vigorous genotypes suffered less severe damage or recovery was faster than in the low-vigour genotypes. Coordination of events at appropriate times would seem a critical factor for proper seed germination.

scholarly journals Heterotrimeric PCNA Increases the Activity and Fidelity of Dbh, a Y-family Translesion DNA Polymerase Prone to Creating Single-Base Deletion Mutations

2020 ◽  
Author(s):  
Yifeng Wu ◽  
William Jaremko ◽  
Ryan C. Wilson ◽  
Janice D. Pata
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
List Type ◽  
Single Base ◽  
Deletion Mutations ◽  
Single Base Deletion ◽  
Translesion Dna ◽  
Y Family

AbstractDbh is a Y-family translesion DNA polymerase from Sulfolobus acidocaldarius, an archaeal species that grows in harsh environmental conditions. Biochemically, Dbh displays a distinctive mutational profile, creating single-base deletion mutations at extraordinarily high frequencies (up to 50%) in specific repeat sequences. In cells, however, Dbh does not appear to contribute significantly to spontaneous frameshifts in these same sequence contexts. This suggests that either the error-prone DNA synthesis activity of Dbh is reduced in vivo and/or Dbh is restricted from replicating these sequences. Here, we test the hypothesis that the propensity for Dbh to make single base deletion mutations is reduced through interaction with the S. acidocaldarius heterotrimeric sliding clamp processivity factor, PCNA-123. We first confirm that Dbh physically interacts with PCNA-123, with the interaction requiring both the PCNA-1 subunit and the C-terminal 10 amino acids of Dbh, which contain a predicted PCNA-interaction peptide (PIP) motif. This interaction stimulates the polymerase activity of Dbh, even on short, linear primer-template DNA by increasing the rate of nucleotide incorporation. This stimulation requires an intact PCNA-123 heterotrimer and a DNA duplex length of at least 18 basepairs, the minimal length predicted from structural data to bind to both the polymerase and the clamp. Finally, we find that PCNA-123 increases the fidelity of Dbh on a single-base deletion hotspot sequence 3-fold by promoting an increase in the rate of correct, but not incorrect, nucleotide addition and propose that PCNA-123 induces Dbh to adopt a more active conformation that is less prone to creating deletions during DNA synthesis.HighlightsPCNA increases the fidelity of Dbh polymerase on a deletion-hotspot sequence.The interaction stimulates incorporation of the correct, but not incorrect, nucleotide.A minimal duplex length of 18 bp is required for PCNA to stimulate polymerase activity.Structural modeling suggests that PCNA induces a conformational change in Dbh.

Differential expression of leaf proteome of tolerant and susceptible maize (Zea mays L.) genotypes in response to multiple abiotic stresses

2019 ◽  
Vol 97 (5) ◽  
pp. 581-588
Author(s):  
Suphia Rafique
Keyword(s):  
Zea Mays L ◽  
Stress Conditions ◽  
Physiological Status ◽  
Maize Seedlings ◽  
Tropical Maize ◽  
Combined Stress ◽  
Two Dimensional Gel Electrophoresis ◽  
Maize Genotypes ◽  
The Given ◽  
Physiological And Biochemical

In the present work, tropical maize genotypes were evaluated for multiple stresses (drought × low-N and waterlogging × low-N) applied simultaneously to 30-day-old maize seedlings. Two-dimensional gel electrophoresis was used to examine the protein changes induced by combined stress, in leaves, of tolerant and susceptible genotypes. Moreover, physiological and biochemical parameters were assessed to understand the physiological status of tolerant and susceptible genotypes under combined stress. The results show that up-regulated proteins of the tolerant genotype have a significant role in activating defense response, restoration of plant growth, and to maintain metabolic homeostasis under stressful conditions. Therefore, they contribute to improve and maintain the state of acclimation of the genotype under stress. Alternatively in the susceptible genotype, the up-regulated proteins are representative biomarkers of stress or are involved in the defense against pathogens and efforts to maintain energy metabolism. Thus, protecting the survival of the genotype under multiple stress conditions. We conclude that depending on the given stress treatment, tolerant and susceptible genotypes differed in stress-enduring approaches. Therefore, the study provides insight to comprehend the response of tolerant and susceptible genotypes under combined stress conditions, which could be valuable for further research and will demonstrate that it is advantageous to select combined stress-tolerant genotypes.

scholarly journals Critical Leaf Magnesium Concentrations for Adequate Photosynthate Production of Soilless Cultured Cherry Tomato—Interaction with Potassium

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1863
Author(s):  
Xilin Guan ◽  
Dunyi Liu ◽  
Bin Liu ◽  
Changchun Wu ◽  
Chuanyun Liu ◽  
...  
Keyword(s):  
Dry Matter ◽  
Photosynthetic Parameters ◽  
Dry Matter Accumulation ◽  
Cherry Tomato ◽  
Biochemical Processes ◽  
Tomato Yield ◽  
Ca Uptake ◽  
Yield Formation ◽  
Physiological And Biochemical ◽  
Dry Matter Weight

Magnesium (Mg) is essential to many plant physiological and biochemical processes; however, understanding how Mg nutrition quantitatively affects the production, partitioning, and utilization of photoassimilates is still lacking, especially in soilless culture systems. We focused on the roles of Mg in yield formation and interactions with potassium (K) nutrition of cherry tomato. Cherry tomato yield, photosynthetic parameters, dry matter weight, and K, Mg, and calcium (Ca) uptake were investigated in two soilless experiments with seven Mg levels and five K levels. The results showed that low (<1 mM) and high (>4 mM) Mg supply limited cherry tomato yield by decreasing dry matter accumulation by 22.6–78.1% and harvest index by 13.9–40.7%. The critical leaf Mg concentrations required for adequate photosynthate production in the first and second harvest periods were 4.67 and 5.52 g·kg−1, respectively. However, over-supply of Mg reduced leaf K and Ca concentrations and limited plant uptake of K and Ca. Moreover, adjusting K concentrations in solution could influence plant Mg functions in photosynthesis and, therefore, cherry tomato growth. Overall, balanced Mg and K application increased Mg, K, and Ca uptake, as well as Mg concentrations in leaves, which could maintain a sustainable photosynthetic rate and plant dry matter formation.

scholarly journals REPAIR DNA SYNTHESIS IN DIFFERENTIATED EMBRYONIC MUSCLE CELLS

1972 ◽  
Vol 52 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Frank E. Stockdale ◽  
Michael C. O'neill
Keyword(s):  
Skeletal Muscle ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Uv Irradiation ◽  
Life Time ◽  
Muscle Cells ◽  
Polymerase Activity ◽  
Repair Synthesis ◽  
Entire Life ◽  
Embryonic Muscle

The differentiation of embryonic skeletal muscle cells is closely coupled with the cessation of normal DNA replication. Once these cells begin to differentiate, they normally never undergo semiconservative replication of DNA during the entire life time of the muscle cell. Cessation of DNA synthesis has been shown to be accompanied by a loss of 80–90% of the replicative DNA polymerase activity of these cells. Despite this loss the studies reported here demonstrate that muscle cells retain the ability to synthesize DNA of a repair type after UV irradiation. These results suggest that the control exercised over semiconservative DNA synthesis during differentiation of these cells does not extend to repair synthesis after UV irradiation.

Effect of benzo[a]pyrene on DNA synthesis and DNA polymerase activity of rat liver nuclei

1985 ◽  
Vol 34 (6) ◽  
pp. 755-762 ◽  
Author(s):  
Inés Salazar ◽  
Laura Tarragó-Litvak ◽  
Simón Litvak ◽  
Lionel Gil
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Rat Liver ◽  
Polymerase Activity ◽  
Rat Liver Nuclei ◽  
Liver Nuclei

scholarly journals Poly(adenosine diphosphate ribose) polymerase activity and nicotinamide adenine dinucleotide in differentiating cardiac muscle

1976 ◽  
Vol 154 (2) ◽  
pp. 387-393 ◽  
Author(s):  
W C. Claycomb
Keyword(s):  
Cyclic Amp ◽  
Dna Synthesis ◽  
Cardiac Muscle ◽  
Dna Polymerase ◽  
Specific Activity ◽  
Polymerase Activity ◽  
Neonatal Rat ◽  
Dibutyryl Cyclic Amp ◽  
Fresh Tissue ◽  
Dna Polymerase Α

Poly(ADP-ribose) polymerase activity in nuclei isolated from differentiating cardiac muscle of the rat has been characterized and its activity measured during development. Optimum enzyme activity is observed at pH 8.5. Poly(ADP-ribose) polymerase is inhibited by ATP, thymidine, nicotinamide, theophylline, 3-isobutyl-1-methylxanthine and caffeine and stimulated by actinomycin D. The activity measured under optimal assay conditions increases during differentiation of cardiac muscle and is inversely related to the rate of DNA synthesis and to the activities of DNA polymerase α and thymidine kinase. When DNA synthesis and the activity of DNA polymerase α are inhibited in cardiac muscle of the 1-day-old neonatal rat by dibutyryl cyclic AMP or isoproterenol, the specific activity of poly(ADP-ribose) polymerase measured in isolated nuclei is increased. The concentration of NAD+ in cardiac muscle increases during postnatal development. In the adult compared with the 1-day-old neonatal rat the concentration of NAD+ relative to fresh tissue weight, DNA or protein increased 1.7-fold, 5.2-fold or 1.4-fold respectively. The concentration of NAD+ in cardiac muscle of the 1-day-old neonatal rat can be increased by approx. 20% by dibutyryl cyclic AMP. These data suggest that NAD+ and poly(ADP-ribose) polymerase may be involved with the repression of DNA synthesis and cell proliferation in differentiating cardiac muscle.

scholarly journals Effect of Seed Ageing in Biochemical and Molecular Changes in Oilseeds: A Review

2020 ◽  
Author(s):  
Induja Sudhakaran
Keyword(s):  
Environmental Factors ◽  
Molecular Changes ◽  
Seed Deterioration ◽  
Physiological Phenomenon ◽  
Seed Ageing

Seed deterioration is the loss of quality, viability and vigour either due to ageing or effect of adverse environmental factors. The process of deterioration is an irresistible physiological phenomenon. The seeds which are stored under suitable conditions may sometime undergo a series of changes which can ultimately result in the deterioration of the quality of the seed. Hence a thorough study should be done in these deteriorative changes so that proper measures can be adopted to control the variations. Therefore in this article the changes within cellular, biochemical and metabolic aspects of long term stored oilseeds are discussed.

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