scholarly journals Effects of phytohormones on thermal denaturation profiles of Cymbidium DNA: Indication of differential DNA replication

1976 ◽  
Vol 3 (8) ◽  
pp. 2033-2040 ◽  
Author(s):  
W. Nagl ◽  
W. Rucker
Keyword(s):  
Dna Replication ◽  
Thermal Denaturation ◽  
Differential Dna Replication

DIFFERENTIAL DNA REPLICATION IN THE XX AND XY CELLS OF MUSCA DOMESTICA L. OCRA STRAIN

1970 ◽  
Vol 12 (3) ◽  
pp. 461-473 ◽  
Author(s):  
K. Y. Jan ◽  
J. W. Boyes
Keyword(s):  
Dna Replication ◽  
Musca Domestica ◽  
Sex Chromosomes ◽  
Chromosome Length ◽  
Final Part ◽  
X Chromosomes ◽  
Y Chromosomes ◽  
Heteromorphic Sex Chromosomes ◽  
Autosomal Pair ◽  
Differential Dna Replication

The karyotype of Musca domestica L. ocra strain, consists of the sex chromosomes and five autosomal pairs. The heteromorphic sex chromosomes are heterochromatic and mitotically unpaired, whereas the autosomes are euchromatic and mitotically paired. All autosomal pairs and both X and Y chromosomes are cytologically recognizable.The relative labelling rate, R (in terms of the number of grains counted per 100 labelled metaphases per μ of chromosome length) for the sex chromosomes and for each autosomal pair was followed from 1.5 hours to 8 hours after H3TdR injection. The pattern of labelling rate was similar for the different autosomal pairs in the XX cells but this pattern for the autosomal pairs in the XY cells, though also similar for the different pairs, differed appreciably from that found in the XX cells. The pattern of the labelling rate for the X chromosomes was similar in the XX and XY cells. Also the pattern of labelling rate for the X and Y chromosomes was similar during the final part of the replication period. The two X chromosomes in the XX cells and the X and Y chromosomes in the XY cells completed labelling later than the autosomes.

scholarly journals Effects of Stability of Base Pairs Containing an Oxazolone on DNA Elongation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Masayo Suzuki ◽  
Kazuya Ohtsuki ◽  
Katsuhito Kino ◽  
Teruhiko Kobayashi ◽  
Masayuki Morikawa ◽  
...  
Keyword(s):  
Dna Replication ◽  
Oxidative Damage ◽  
Ab Initio ◽  
Base Pair ◽  
Thermal Denaturation ◽  
Primer Extension ◽  
Base Pairs ◽  
Nucleotide Incorporation ◽  
The Stability

The nucleoside 2,2,4-triamino-5(2H)-oxazolone (Oz) can result from oxidative damage to guanine residues in DNA. Despite differences among the three polymerases (Polβ, KF exo−, and Polη) regarding nucleotide incorporation patterns opposite Oz, all three polymerases can incorporate guanine opposite Oz. Based onab initiocalculations, we proposed a structure for a stable Oz:G base pair. Here, to assess the stability of each Oz-containing base pair (Oz:G, Oz:A, Oz:C, and Oz:T) upon DNA replication, we determined the efficiency of Polβ-, KF exo−-, or Polη-catalyzed primer extension beyond each base pair. With each polymerase, extension beyond Oz:G was more efficient than that beyond Oz:A, Oz:C, or Oz:T. Moreover, thermal denaturation studies revealed that theTmvalue for the duplex containing Oz:G was significantly higher than those obtained for duplexes containing Oz:A, Oz:C, or Oz:T. Therefore, the results fromab initiocalculations along with those from DNA replication assays and thermal denaturation experiments supported the conclusion that Oz:G is the most stable of the Oz-containing base pairs.

Qualitative changes in DNA indicating differential DNA replication during early embryogenesis of the newt Triturus vulgaris

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 61-70
Author(s):  
Klaus Lohmann ◽  
Lore Schubert
Keyword(s):  
Density Gradient ◽  
Thermal Denaturation ◽  
Significant Rise ◽  
Regular Shape ◽  
Normal Probability ◽  
Cscl Density Gradient ◽  
Triturus Vulgaris ◽  
Differential Dna Replication ◽  
Early Gastrula ◽  
Qualitative Changes

During gastrulation of the newt Triturus vulgaris considerable changes in the meltingbehaviour and in the CsCl density gradient pattern of DNA occur. The melting curves of DNAs from mid to late gastrulae (stages 11 b-12c) deviate from the regular shape. Whereasthe Tm values are identical in the stages 11 a (early gastrula) and 15 (early neurula), and correspond to the standard DNA (stage 36 = tailbud), a significant rise of Tm (0·8–1·2 °C) has been recorded in the stages 12 a/b (yolk plug). The differences in melting behaviour become visible by the deviation of the curves above Tm. These deviations from the normal sigmoidal shape are caused by the fact that a portion of DNA melts at higher temperatures than usual. Therefore the thermal denaturation of DNA is completed at approximately 3–4 °C later than in standard DNA. Both the derivative curves and the plots on normal probability paper demonstrate a heterogeneity of DNA in the stages 11 b-12c which indicates the presence of an additional GC-rich satellite fraction. These findings are confirmed by CsCl density gradient studies. Thus, in the stages 12a/b a slight shoulder on the heavy side of the gradients occurs, being absent in the other stages. From these facts we have to conclude that there is a stage-dependent multiplication and elimination of GC-rich sequences.

A DNA cytophotometric and chromosome banding study in Hedera helix (Araliaceae), with reference to differential DNA replication associated with juvenile–adult phase change

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 498-503 ◽  
Author(s):  
C. König ◽  
I. Ebert ◽  
J. Greilhuber
Keyword(s):  
Dna Replication ◽  
Genome Size ◽  
Chromosome Banding ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Developmental Phase ◽  
Hedera Helix ◽  
Leaf Tissues ◽  
Differential Dna Replication ◽  
Developmental Phases

The present DNA cytophotometric and chromosome banding comparison of the juvenile and the adult developmental phase in the common ivy, Hedera helix, was undertaken as an attempt to verify or refute the asserted phase-correlated differential DNA replication in this plant. No statistically significant differences between the two developmental phases were found in genome size (as determined from mitotic nuclei), nuclear DNA content in resting meristems and somatic leaf tissues, and content of constitutive heterochromatin as measured from C-banded metaphase plates. There is no evidence for differential DNA replication in Hedera helix. Key words: Hedera helix, differential DNA replication, morphogenesis, genome size, chromosome structure.

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