scholarly journals Purine metabolism in mesophyll protoplasts of tobacco (Nicotiana tabacum) leaves

1980 ◽  
Vol 186 (1) ◽  
pp. 343-350 ◽  
Author(s):  
J Barankiewicz ◽  
J Paszkowski
Keyword(s):  
Nucleic Acid ◽  
Nicotiana Tabacum ◽  
Nucleic Acids ◽  
Metabolic Pathways ◽  
Rna Synthesis ◽  
Acid Fraction ◽  
Purine Nucleotide ◽  
Tobacco Leaf ◽  
Mesophyll Protoplasts ◽  
Leaf Mesophyll

The overall metabolism of purines was studied in tobacco (Nicotiana tabacum) mesophyll protoplasts. Metabolic pathways were studied by measuring the conversion of radioactive adenine, adenosine, hypoxanthine and guanine into purine ribonucleotides, ribonucleosides, bases and nucleic acid constituents. Adenine was extensively deaminated to hypoxanthine, whereupon it was also converted into AMP and incorporated into nucleic acids. Adenosine was mainly hydrolysed to adenine. Inosinate formed from hypoxanthine was converted into AMP and GMP, which were then catabolized to adenine and guanosine respectively. Guanine was mainly deaminated to xanthine and also incorporated into nucleic acids via GTP. Increased RNA synthesis in the protoplasts resulted in enhanced incorporation of adenine and guanine, but not of hypoxanthine and adenosine, into the nucleic acid fraction. The overall pattern of purine-nucleotide metabolic pathways in protoplasts of tobacco leaf mesophyll is proposed.

Insulin and incorporation of radioactivity into nucleic acid fraction of isolated diaphragm

1960 ◽  
Vol 199 (4) ◽  
pp. 719-721 ◽  
Author(s):  
Ira G. Wool
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Glucose Concentration ◽  
Orotic Acid ◽  
Acid Fraction ◽  
Rat Diaphragm ◽  
Isolated Rat

Insulin in vitro stimulated the incorporation into the nucleic acid fraction of isolated rat diaphragm of radioactivity from d-glucose-U-C14, adenine-8-C14 and orotic acid-6-C14; insulin had no effect on the incorporation of thymine-2-C14 into muscle nucleic acids. Insulin enhanced the incorporation into nucleic acids of C14 from adenine and orotic acid in the absence of added glucose, and incorporation of adenine-8-C14 was not influenced by glucose concentration over the range 0–600 mg %.

scholarly journals Influence of hydroxyurea on nucleic acids content and 3H-uridine incorporation in callus and tumorous tobacco tissues cultured in vitro

2015 ◽  
Vol 44 (3) ◽  
pp. 393-405
Author(s):  
A. Bielecka
Keyword(s):  
Nicotiana Tabacum ◽  
Nucleic Acids ◽  
Dna Content ◽  
Incubation Medium ◽  
Rna Synthesis ◽  
Callus Tissue ◽  
Tumour Tissue ◽  
Inhibitory Influence ◽  
Tumor Tissues

In callus and tumor tissues of <i>Nicotiana tabacum</i> cultured for 39 days in media supplemented with various concentrations of hydroxyurea (1.3 x 10<sup>-4</sup> M - 1.3 x 10<sup>-3</sup> M) a decrease of DNA content (ca. 24 per cent in callus tissue and ca. 23 per cent in tumour tissue) and a decrease of RNA content (over 10 per cent and ca. 9 per cent in callus and tumour tissue, respectively) was observed. The autoradiographic method showed that a long-lasting action of this com-pound inhibits RNA synthesis. A stronger inhibitory influence of hydroxyurea upon incorporation of 3H-uridine from the incubation medium was revealed.

Fixation of nucleic acid by leaf fibre and calcium phosphate

1974 ◽  
Vol 185 (1080) ◽  
pp. 343-356 ◽  
Keyword(s):  
Nucleic Acid ◽  
Calcium Phosphate ◽  
Nucleic Acids ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Deoxyribonucleic Acid ◽  
Leaf Extracts ◽  
Tobacco Leaves ◽  
Tobacco Leaf ◽  
Ribonucleic Acids

Calcium phosphate co-precipitates half its mass of ribonucleic acids made from yeast, tobacco leaf and tobacco mosaic virus when the precipitate is formed in their presence. It also precipitates deoxyribonucleic acid. Degraded nucleic acids are less completely precipitated. Less nucleic acid is adsorbed by preformed calcium phosphate. In suitable circumstances nucleic acid is fixed by leaf fibre. Autolytic changes in leaf fibre, and in calcium-chelators in leaf extracts, explain many differences in the amount of nucleic acid present in extracts made from tobacco leaves in different ways.

scholarly journals Nucleic acid synthesis and nucleotide pools in purine-deficient Escherichia coli

1970 ◽  
Vol 120 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Gillian A. Thomas ◽  
N. F. Varney ◽  
K. Burton
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Rna Synthesis ◽  
Adenine Nucleotides ◽  
Acid Synthesis ◽  
Purine Nucleotides ◽  
Low Concentration ◽  
Intracellular Atp ◽  
Nucleotide Pools

1. The synthesis of nucleic acids and the content of purine nucleotides have been studied in selected purine-requiring strains of Escherichia coli including a purB− strain and a purB−guaA− strain. 2. When the exogenous purines can be converted into GTP but not into ATP, RNA is synthesized at the expense of intracellular ATP, ADP and AMP. 3. Net synthesis of RNA as measured by the incorporation of uracil can be correlated with the availability of GTP except when ATP falls to a very low concentration. 4. Nicotinamide nucleotides are not an important reservoir of adenine nucleotides for RNA synthesis.

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 Mycobacterial HelD is a nucleic acids-clearing factor for RNA polymerase

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomáš Kouba ◽  
Tomáš Koval’ ◽  
Petra Sudzinová ◽  
Jiří Pospíšil ◽  
Barbora Brezovská ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Rna Polymerase ◽  
Active Site ◽  
Mycobacterium Smegmatis ◽  
Rna Synthesis ◽  
Environmental Changes ◽  
Transcription Elongation ◽  
Specific Interactions ◽  
Inactive State ◽  
Transcription Machinery

AbstractRNA synthesis is central to life, and RNA polymerase (RNAP) depends on accessory factors for recovery from stalled states and adaptation to environmental changes. Here, we investigated the mechanism by which a helicase-like factor HelD recycles RNAP. We report a cryo-EM structure of a complex between the Mycobacterium smegmatis RNAP and HelD. The crescent-shaped HelD simultaneously penetrates deep into two RNAP channels that are responsible for nucleic acids binding and substrate delivery to the active site, thereby locking RNAP in an inactive state. We show that HelD prevents non-specific interactions between RNAP and DNA and dissociates stalled transcription elongation complexes. The liberated RNAP can either stay dormant, sequestered by HelD, or upon HelD release, restart transcription. Our results provide insights into the architecture and regulation of the highly medically-relevant mycobacterial transcription machinery and define HelD as a clearing factor that releases RNAP from nonfunctional complexes with nucleic acids.

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.

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