Physical characteristics of DNA from bacteriophages of Agrobacterium tumefaciens

1976 ◽  
Vol 22 (10) ◽  
pp. 1583-1585 ◽  
Author(s):  
R. J. Manasse ◽  
R. C. Staples
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Dna Hybridization ◽  
Physical Characteristics ◽  
Molecular Weights ◽  
Phage Dna

DNA was extracted from isolates of bacteriophages grown on virulent and avirulent strains of Agrobacterium tumefaciens. Molecular weights of DNA from phages isolated from the virulent A. tumefaciens (IIBV7) were about 41.5 × 106 daltons, while those from the avirulent A. tumefaciens (IIBNV6) were about 32.5 × 106 daltons. The buoyant densities of the four DNA's ranged from 1.7086 to 1.7089 g/cm3 values that were not significantly different. DNA–DNA hybridization studies also indicated that the four phages were closely related. Attempts to induce tumors with phage DNA were unsuccessful.

Incorporation of T4 Phage DNA into a Specific DNA Fraction from the Higher Plant Matthiola incana

1976 ◽  
Vol 31 (9-10) ◽  
pp. 558-564 ◽  
Author(s):  
Waltraud Gradmann-Rebel ◽  
Vera Hemleben
Keyword(s):  
Dna Sequences ◽  
Dna Hybridization ◽  
Plant Cells ◽  
High Density ◽  
Higher Plant ◽  
Matthiola Incana ◽  
Plant Dna ◽  
Phage Dna ◽  
T4 Phage ◽  
Dna Density

Abstract Isolated T4 phage DNA (ϱ = 1.694 g/ml) is applied to seedlings of the crucifer Maltliiola incana (DNA density ϱ = 1.698 g/ml). The phage DNA can partly be reextracted from the plants in a specific DNA fraction, which is predominantly characterized by its unusual high density (high density complex = HDC; ϱ = 1.724 g/ml). DNA: DNA hybridization studies show that phage specific DNA sequences are preserved in the HDC. Results of BrdUrd labeling of the plant DNA before and during incubation with T4 DNA suggest that the HDC is composed of T4 DNA and a plant DNA component of high density. The analysis of ultrasonicated HDC confirms this suggestion. The ability of plant cells to recognize and handle T4 DNA specifically is discussed.

Agrobacterium-mediated transformation of large-flowered purslane (Portulaca grandiflora H.)

Genome ◽  
1995 ◽  
Vol 38 (4) ◽  
pp. 752-756 ◽  
Author(s):  
Badr-Din Rossi-Hassani ◽  
Fadoua Bennani ◽  
Jean-Pierre Zryd
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Dna Hybridization ◽  
Segregation Analysis ◽  
Binary Vector ◽  
Dna Transfer ◽  
Antibiotic Resistant ◽  
Portulaca Grandiflora ◽  
Resistant Progeny ◽  
Vector Dna ◽  
Selection Of

Transformation of Portulaca grandiflora has been developed with Agrobacterium tumefaciens strains A281 and T1272. Transformation was assessed by the following criteria: selection of hormone independent callus, antibiotic-resistant callus, and transgenic antibiotic-resistant plants. In addition, DNA hybridization analysis demonstrated that the DNA from tumor lines contained sequences homologous to binary vector T-DNA of strain A281. Following transformation with strain T1272, segregation analysis of the progeny of transgenic plants showed that the transgene was inherited in a Mendelian manner. The kanamycin-resistant progeny tested contained the T-DNA sequence of the strain T1272.Key words: Agrobacterium tumefaciens, binary vector, DNA transfer, regeneration, Portulaca grandiflora.

scholarly journals Particle Size Affects Concentration-Dependent Cytotoxicity of Chitosan Nanoparticles towards Mouse Hematopoietic Stem Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Siti Sarah Omar Zaki ◽  
Mohd Nazmi Ibrahim ◽  
Haliza Katas
Keyword(s):  
Stem Cells ◽  
Molecular Weight ◽  
Particle Size ◽  
Zeta Potential ◽  
Hematopoietic Stem Cells ◽  
Chitosan Nanoparticles ◽  
Physical Characteristics ◽  
Hematopoietic Stem ◽  
Molecular Weights ◽  
Chitosan Concentration

Chitosan nanoparticles (CSNPs) have been extensively applied in medical and pharmaceutical fields as promising drug delivery systems. Despite that, the safety of CSNPs remains inadequate and needs further investigation, particularly on hematopoietic stem cells (HSCs). CSNPs were prepared by ionic gelation method and later were characterized for their physical characteristics (particle size and zeta potential). Cytotoxicity of CSNPs was assessed by MTT assay. Particle size was highly influenced by chitosan concentration and molecular weight (medium and high molecular weight (MMW and HMW)). Higher chitosan concentration and molecular weight produced larger nanoparticles. Zeta potential of CSNPs was not significantly affected by chitosan concentrations and molecular weights used in the present study. MMW had a better stability than HMW CSNPs as their particle size and zeta potential were not significantly altered after autoclaving. Cytotoxicity of CSNPs was influenced by zeta potential and particle size. On the other hand, chitosan concentration and molecular weight indirectly influenced cytotoxicity by affecting particle size and zeta potential of CSNPs. In conclusion, cytotoxicity of CSNPs was mainly attributed to their physical characteristics and this opens a strategy to ensure the safety of CSNPs applications in stem cell technology.

scholarly journals Detection of tumor-inducing plasmid DNA sequence in agrobacterium tumefaciens by DNA-DNA hybridization.

RADIOISOTOPES ◽  
1984 ◽  
Vol 33 (8) ◽  
pp. 543-546 ◽  
Author(s):  
Kazuhiko FURUKAWA ◽  
Kohji HASUNUMA ◽  
Shin-ichi HATANAKA ◽  
Toshio HAYASHI
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Dna Sequence ◽  
Plasmid Dna ◽  
Dna Hybridization

scholarly journals Snapshot of the Genome of the Pseudo-T-Even Bacteriophage RB49

2002 ◽  
Vol 184 (10) ◽  
pp. 2789-2804 ◽  
Author(s):  
Carine Desplats ◽  
Christophe Dez ◽  
Françoise Tétart ◽  
Heïdy Eleaume ◽  
H. M. Krisch
Keyword(s):  
Dna Replication ◽  
Dna Hybridization ◽  
Common Ancestor ◽  
Regulatory Sequences ◽  
Last Common Ancestor ◽  
Phage T4 ◽  
Regulatory Strategies ◽  
Intergenic Sequences ◽  
Phage Dna ◽  
Blastn Analysis

ABSTRACT RB49 is a virulent bacteriophage that infects Escherichia coli. Its virion morphology is indistinguishable from the well-known T-even phage T4, but DNA hybridization indicated that it was phylogenetically distant from T4 and thus it was classified as a pseudo-T-even phage. To further characterize RB49, we randomly sequenced small fragments corresponding to about 20% of the ≈170-kb genome. Most of these nucleotide sequences lacked sufficient homology to T4 to be detected in an NCBI BlastN analysis. However, when translated, about 70% of them encoded proteins with homology to T4 proteins. Among these sequences were the numerous components of the virion and the phage DNA replication apparatus. Mapping the RB49 genes revealed that many of them had the same relative order found in the T4 genome. The complete nucleotide sequence was determined for the two regions of RB49 genome that contain most of the genes involved in DNA replication. This sequencing revealed that RB49 has homologues of all the essential T4 replication genes, but, as expected, their sequences diverged considerably from their T4 homologues. Many of the nonessential T4 genes are absent from RB49 and have been replaced by unknown sequences. The intergenic sequences of RB49 are less conserved than the coding sequences, and in at least some cases, RB49 has evolved alternative regulatory strategies. For example, an analysis of transcription in RB49 revealed a simpler pattern of regulation than in T4, with only two, rather than three, classes of temporally controlled promoters. These results indicate that RB49 and T4 have diverged substantially from their last common ancestor. The different T4-type phages appear to contain a set of common genes that can be exploited differently, by means of plasticity in the regulatory sequences and the precise choice of a large group of facultative genes.

scholarly journals Encoding function into polypeptide-oligonucleotide precision biopolymers

2018 ◽  
Vol 54 (83) ◽  
pp. 11797-11800 ◽  
Author(s):  
Weina Liu ◽  
Felix Boldt ◽  
Yu Tokura ◽  
Tao Wang ◽  
Bikram Keshari Agrawalla ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Molecular Weights ◽  
Novel Synthesis ◽  
Synthesis Strategy ◽  
Chain Lengths

We report a novel synthesis strategy to prepare precision polymers providing exact chain lengths, molecular weights and monomer sequences that allow post modifications by convenient DNA hybridization.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Characterization of microtubules by dark-field STEM and replication

1991 ◽  
Vol 49 ◽  
pp. 152-153
Author(s):  
S.B. Andrews ◽  
R.D. Leapman ◽  
P.E. Gallant ◽  
T.S. Reese
Keyword(s):  
Protein Interactions ◽  
Low Dose ◽  
Unit Length ◽  
Dark Field ◽  
Carbon Films ◽  
Microtubule Associated Proteins ◽  
Molecular Weights ◽  
Freeze Dried ◽  
Protein Motors ◽  
Associated Proteins

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen (ca. -185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled to ca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.

Electron Microscope Study of RNA's of Paramyxoviruses

1972 ◽  
Vol 30 ◽  
pp. 196-197
Author(s):  
Ruchama Baum ◽  
J.T. Seto
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Sendai Virus ◽  
Sodium Dodecyl ◽  
Rna Molecules ◽  
Virus Particles ◽  
Molecular Weights ◽  
Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

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