scholarly journals Biosynthesis of caffeine in tea callus tissue

1970 ◽  
Vol 117 (4) ◽  
pp. 715-720 ◽  
Author(s):  
D. B. A. Ogutuga ◽  
D. H. Northcote
Keyword(s):  
Carbon Dioxide ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Callus Tissue ◽  
Radioactive Carbon ◽  
Caffeine Biosynthesis

1. A study of caffeine biosynthesis has been made by following the incorporation of radioactive carbon dioxide and methionine into the methylated purines produced by tea callus tissue. 2. The uptake of the radioactive labels into nucleic acid and caffeine was followed over a period of approximately 9h. 3. The distribution of the radioactive labels in both nucleic acid and caffeine was determined after incorporation and subsequent incubation of the tissue in a non-radioactive medium. 4. The results of the experiments indicated that the caffeine arose from purines released from the breakdown of nucleic acids rather than that it was formed directly from a purine pool. 5. A metabolic scheme to show the production of caffeine from the nucleotides of the nucleic acid is discussed.

ON THE INCORPORATION OF LABELLED ADENINE INTO THE PURINES OF THE NUCLEIC ACIDS IN THE RAT

1957 ◽  
Vol 35 (1) ◽  
pp. 1189-1196
Author(s):  
R. V. Tomlinson ◽  
S. H. Zbarsky
Keyword(s):  
Carbon Dioxide ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Metabolic Conversion ◽  
Purine Ring

Adenine labelled with C14 in position 2 and with N15 in positions 1 and 3 was injected intraperitoneally into rats, and the purines of the nucleic acids from the pooled viscera were isolated. The C14/N15 ratios of the isolated adenine and guanine were considerably lower than that of the injected adenine, indicating that during the formation of the nucleic acid purines from the administered material there was a loss of C14 relative to N15. This loss was larger for the guanine, which had a C14/N15 ratio 52–67% lower than that of the injected adenine. Metabolic removal of carbon 2 of the adenine was shown further by the excretion of 22% of the injected radioactivity as respiratory carbon dioxide. Fifty-three per cent of the administered radioactivity was excreted in the urine and of this less than half was accounted for as allantoin, adenine, and urea. The C14/N15 ratio of the urinary allantoin was intermediate in value between those of the adenine and guanine. The evidence obtained indicates that during the metabolic conversion of adenine to guanine the purine ring may undergo rupture at the 2 position. A possible mechanism for the reaction is presented.

ON THE INCORPORATION OF LABELLED ADENINE INTO THE PURINES OF THE NUCLEIC ACIDS IN THE RAT

1957 ◽  
Vol 35 (12) ◽  
pp. 1189-1196 ◽  
Author(s):  
R. V. Tomlinson ◽  
S. H. Zbarsky
Keyword(s):  
Carbon Dioxide ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Metabolic Conversion ◽  
Purine Ring

Adenine labelled with C14 in position 2 and with N15 in positions 1 and 3 was injected intraperitoneally into rats, and the purines of the nucleic acids from the pooled viscera were isolated. The C14/N15 ratios of the isolated adenine and guanine were considerably lower than that of the injected adenine, indicating that during the formation of the nucleic acid purines from the administered material there was a loss of C14 relative to N15. This loss was larger for the guanine, which had a C14/N15 ratio 52–67% lower than that of the injected adenine. Metabolic removal of carbon 2 of the adenine was shown further by the excretion of 22% of the injected radioactivity as respiratory carbon dioxide. Fifty-three per cent of the administered radioactivity was excreted in the urine and of this less than half was accounted for as allantoin, adenine, and urea. The C14/N15 ratio of the urinary allantoin was intermediate in value between those of the adenine and guanine. The evidence obtained indicates that during the metabolic conversion of adenine to guanine the purine ring may undergo rupture at the 2 position. A possible mechanism for the reaction is presented.

Nucleic Acid Molecules Prepared by Monolayer Techniques

1972 ◽  
Vol 30 ◽  
pp. 178-179
Author(s):  
Dimitrij Lang
Keyword(s):  
Electron Microscopy ◽  
Standard Deviation ◽  
Nucleic Acid ◽  
Cytochrome C ◽  
Nucleic Acids ◽  
Contour Length ◽  
Sample Standard Deviation ◽  
Molecular Weights ◽  
Length Measurements ◽  
Protein Monolayer

The success of the protein monolayer technique for electron microscopy of individual DNA molecules is based on the prevention of aggregation and orientation of the molecules during drying on specimen grids. DNA adsorbs first to a surface-denatured, insoluble cytochrome c monolayer which is then transferred to grids, without major distortion, by touching. Fig. 1 shows three basic procedures which, modified or not, permit the study of various important properties of nucleic acids, either in concert with other methods or exclusively:1) Molecular weights relative to DNA standards as well as number distributions of molecular weights can be obtained from contour length measurements with a sample standard deviation between 1 and 4%.

Snapshot blotting: The transfer of nucleic acids and nucleoprotein complexes from electrophoresis gels to EM grids

1992 ◽  
Vol 50 (1) ◽  
pp. 762-763
Author(s):  
Stephen D. Jett
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Nucleic Acid Binding ◽  
Mobility Shift ◽  
Carbon Coated ◽  
Nucleoprotein Complexes ◽  
Mobility Shift Assay ◽  
Protein Nucleic Acid ◽  
Gel Mobility Shift ◽  
Nucleic Acid Interactions

The electrophoresis gel mobility shift assay is a popular method for the study of protein-nucleic acid interactions. The binding of proteins to DNA is characterized by a reduction in the electrophoretic mobility of the nucleic acid. Binding affinity, stoichiometry, and kinetics can be obtained from such assays; however, it is often desirable to image the various species in the gel bands using TEM. Present methods for isolation of nucleoproteins from gel bands are inefficient and often destroy the native structure of the complexes. We have developed a technique, called “snapshot blotting,” by which nucleic acids and nucleoprotein complexes in electrophoresis gels can be electrophoretically transferred directly onto carbon-coated grids for TEM imaging.

Molecular insights on the dynamic stability of peptide nucleic acid functionalized carbon and boron nitride nanotubes

2021 ◽  
Vol 23 (1) ◽  
pp. 219-228
Author(s):  
Nabanita Saikia ◽  
Mohamed Taha ◽  
Ravindra Pandey
Keyword(s):  
Nucleic Acid ◽  
Boron Nitride ◽  
Nucleic Acids ◽  
Dynamic Stability ◽  
Peptide Nucleic Acid ◽  
Rational Design ◽  
Peptide Nucleic Acids ◽  
Boron Nitride Nanotubes ◽  
Molecular Hybrids ◽  
Single Wall Nanotubes

The rational design of self-assembled nanobio-molecular hybrids of peptide nucleic acids with single-wall nanotubes rely on understanding how biomolecules recognize and mediate intermolecular interactions with the nanomaterial's surface.

Application strategies of peptide nucleic acids toward electrochemical nucleic acid sensors

The Analyst ◽  
2021 ◽  
Author(s):  
Qingteng Lai ◽  
Wei Chen ◽  
Yanke Zhang ◽  
Zheng-Chun Liu
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Peptide Nucleic Acids ◽  
Dna Probes ◽  
Highly Sensitive ◽  
Increased Sensitivity ◽  
Acid Sensors

Peptide nucleic acids (PNAs) have attracted tremendous interest in the fabrication of highly sensitive electrochemical nucleic acid biosensor due to their higher stability and increased sensitivity than common DNA probes....

scholarly journals Validating DNA Extraction Protocols for Bentonite Clay

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Katja Engel ◽  
Sara Coyotzi ◽  
Melody A. Vachon ◽  
Jennifer R. McKelvie ◽  
Josh D. Neufeld
Keyword(s):  
Microbial Community ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Dna Extraction ◽  
Genomic Dna ◽  
Bentonite Clay ◽  
Dna Recovery ◽  
Blocking Agents ◽  
Clay Matrix ◽  
Microbial Dna

ABSTRACT Bentonite clay is an integral component of the engineered barrier system of deep geological repositories (DGRs) that are planned for the long-term storage of high-level radioactive waste. Although nucleic acid extraction and analysis can provide powerful qualitative and quantitative data reflecting the presence, abundance, and functional potential of microorganisms within DGR materials, extraction of microbial DNA from bentonite clay is challenging due to the low biomass and adsorption of nucleic acids to the charged clay matrix. In this study, we used quantitative PCR, gel fingerprinting, and high-throughput sequencing of 16S rRNA gene amplicons to assess DNA extraction efficiency from natural MX-80 bentonite and the same material “spiked” with Escherichia coli genomic DNA. Extraction protocols were tested without additives and with casein and phosphate as blocking agents. Although we demonstrate improved DNA recovery by blocking agents at relatively high DNA spiking concentrations, at relatively low spiking concentrations, we detected a high proportion of contaminant nucleic acids from blocking agents that masked sample-specific microbial profile data. Because bacterial genomic DNA associated with casein preparations was insufficiently removed by UV treatment, casein is not recommended as an additive for DNA extractions from low-biomass samples. Instead, we recommend a kit-based extraction protocol for bentonite clay without additional blocking agents, as tested here and validated with multiple MX-80 bentonite samples, ensuring relatively high DNA recoveries with minimal contamination. IMPORTANCE Extraction of microbial DNA from MX-80 bentonite is challenging due to low biomass and adsorption of nucleic acid molecules to the charged clay matrix. Blocking agents improve DNA recovery, but their impact on microbial community profiles from low-biomass samples has not been characterized well. In this study, we evaluated the effect of casein and phosphate as blocking agents for quantitative recovery of nucleic acids from MX-80 bentonite. Our data justify a simplified framework for analyzing microbial community DNA associated with swelling MX-80 bentonite samples within the context of a deep geological repository for used nuclear fuel. This study is among the first to demonstrate successful extraction of DNA from Wyoming MX-80 bentonite.

scholarly journals Peptide Nucleic Acids: Applications in Biomedical Sciences

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3317
Author(s):  
Eylon Yavin
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Peptide Nucleic Acid ◽  
Peptide Nucleic Acids ◽  
Biomedical Sciences

The DNA mimic, PNA (peptide nucleic acid), has been with us now for almost 3 decades [...]

scholarly journals Visible Light Photochemical Reactions for Nucleic Acid-Based Technologies

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 556
Author(s):  
Bonwoo Koo ◽  
Haneul Yoo ◽  
Ho Jeong Choi ◽  
Min Kim ◽  
Cheoljae Kim ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Visible Light ◽  
Chemical Reactions ◽  
Chemical Biology ◽  
Photochemical Reactions ◽  
Reaction Conditions ◽  
Promising Tool ◽  
Recent Developments ◽  
Visible Light Driven

The expanding scope of chemical reactions applied to nucleic acids has diversified the design of nucleic acid-based technologies that are essential to medicinal chemistry and chemical biology. Among chemical reactions, visible light photochemical reaction is considered a promising tool that can be used for the manipulations of nucleic acids owing to its advantages, such as mild reaction conditions and ease of the reaction process. Of late, inspired by the development of visible light-absorbing molecules and photocatalysts, visible light-driven photochemical reactions have been used to conduct various molecular manipulations, such as the cleavage or ligation of nucleic acids and other molecules as well as the synthesis of functional molecules. In this review, we describe the recent developments (from 2010) in visible light photochemical reactions involving nucleic acids and their applications in the design of nucleic acid-based technologies including DNA photocleaving, DNA photoligation, nucleic acid sensors, the release of functional molecules, and DNA-encoded libraries.

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