scholarly journals GUANINEHEXOSIDE OBTAINED ON HYDROLYSIS OF THYMUS NUCLEIC ACID

1912 ◽  
Vol 12 (3) ◽  
pp. 377-379
Author(s):  
P.A. Levene ◽  
W.A. Jacobs
Keyword(s):  
Nucleic Acid ◽  
Hydrolysis Of

Effect of Cytokinins on the Expansion and Metabolism of Excised Cucumber Cotyledons

1980 ◽  
Vol 7 (3) ◽  
pp. 227
Author(s):  
C Tsui ◽  
Tao Guo-qing ◽  
Chen Hui-ying ◽  
Son Yan-ru ◽  
Lian Han-ping ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Acid Synthesis ◽  
Cell Number ◽  
Cucumis Sativus L ◽  
Biochemical Processes ◽  
Dna And Rna ◽  
Lag Period ◽  
Hydrolysis Of

Expansion of excised cucumber (Cucumis sativus L.) cotyledons was stimulated by treatment with cytokinin, and commenced after a lag period of about 4 h. Expansion induced by benzyladenine (BA) was due mainly to increase of fresh weight, but cell number increased slightly. Hydrolysis of protein and lipid was stimulated by BA, and soluble sugars increased simultaneously. However, there was no significant change in the dry weight of cotyledons during the period of expansion. It is assumed that the transformation of lipid to sugar in the cotyledon is stimulated by BA. The respiration of cotyledons was evidently stimulated by BA and was entirely inhibited by respiratory inhibitors, e.g. NaN,, malonate and dinitrophenol. Inhibitors of protein and nucleic acid synthesis, such as chloramphenicol and actinomycin D, inhibited only the BA-induced expansion. They had no effect on the expansion of controls. These results suggest that different biochemical processes are involved in the expansion of cotyledons induced by BA and in controls. The former is related not only to respiration but also to the synthesis of protein and nucleic acid. BA increased DNA and RNA content per cotyledon. The increase of total RNA is due mainly to the increase of 25 S and 18 S rRNA.

Nucleoapzymes: catalyst-aptamer conjugates as enzyme-mimicking structures

2019 ◽  
Vol 3 (5) ◽  
pp. 493-499 ◽  
Author(s):  
Verena Wulf ◽  
Itamar Willner
Keyword(s):  
Nucleic Acid ◽  
Variable Structure ◽  
Structural Diversity ◽  
Research Field ◽  
Dynamic Simulations ◽  
Catalytic Function ◽  
Enzyme Mimicking ◽  
G Quadruplex ◽  
Catalytic Sites ◽  
Hydrolysis Of

The conjugation of catalytic sites to sequence-specific, ligand-binding nucleic acid aptamers yields functional catalytic ensembles mimicking the catalytic/binding properties of native enzymes. These catalyst-aptamer conjugates termed ‘nucleoapzymes’ reveal structural diversity, and thus, vary in their catalytic activity, due to the different modes of conjugation of the catalytic units to the nucleic acid aptamer scaffold. The concept of nucleoapzymes is introduced with the assembly of a set of catalysts consisting of the hemin/G-quadruplex DNAzyme (hGQ) conjugated to the dopamine aptamer. The nucleoapzymes catalyze the oxidation of dopamine by H2O2 to yield aminochrome. The catalytic processes are controlled by the structures of the nucleoapzymes, and chiroselective oxidation of l-DOPA and d-DOPA by the nucleoapzymes is demonstrated. In addition, the conjugation of a Fe(III)-terpyridine complex to the dopamine aptamer and of a bis-Zn(II)-pyridyl-salen-type complex to the ATP-aptamer yields hybrid nucleoapzymes (conjugates where the catalytic site is not a biomolecule) that catalyze the oxidation of dopamine to aminochrome by H2O2 and the hydrolysis of ATP to ADP, respectively. Variable, structure-controlled catalytic activities of the different nucleoapzymes are demonstrated. Molecular dynamic simulations are applied to rationalize the structure-catalytic function relationships of the different nucleoapzymes. The challenges and perspectives of the research field are discussed.

Remarkable preservation of biomolecules in ancient radish seeds

1996 ◽  
Vol 263 (1370) ◽  
pp. 541-547 ◽  
Keyword(s):  
Fatty Acids ◽  
Nucleic Acid ◽  
Archaeological Remains ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Isotopic Shifts ◽  
Archaeobotanical Remains ◽  
Nucleic Acid Analysis ◽  
Polymerase Chain ◽  
Hydrolysis Of

Desiccated seeds from a 6th century AD storage vessel recovered from Qasr Ibrim, Egypt, were examined for the presence of lipids and nucleic acids. A remarkable degree of lipid preservation was discovered, the fatty acid and sterol profiles being very similar to those of modern radish seeds. The only significant differences were hydrolysis of triacylglycerols and depletion of the polyunsaturated fatty acids (C 18:2 and C 18:3 ). The δ 13 C values of the principal fatty acids were in the range –25.4 to –29.2%0/00, which is congruent with modern radish (C 3 seeds) taking account of isotopic shifts caused by recent changes in atmospheric CO 2 . Deoxyribonucleosides and nucleic acid bases were detected by direct chemical analysis, and polymerase chain reactions gave products with sequences comparable to those from modern radish. The degree of lipid preservation, which was much greater than that reported for other archaeological remains, suggests that the microenvironment within desiccated seeds retards biomolecular decay. The results illustrate the utility of combined lipid-nucleic acid analysis in chemotaxonomic and genotypic studies of archaeobotanical remains.

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