Adsorption of DNA molecules to different support films

Sogo, José M.; Portmann, Rudolf; Kaufmann, Peter; Roller, Th.

doi:10.1111/j.1365-2818.1975.tb04016.x

Cited by 22 publications

(10 citation statements)

References 18 publications

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“…Pictures obtained were only in grey and thus, detection of pollen was more difficult and time‐consuming, and the magnification was too high so that the visualized area was too small for counting. Moreover, the preparation technique is time‐consuming and from our experience with specimen preparation for electron microscopy [ 34], it is speculated that loosely‐bound pollen might be lost during the specimen preparation steps. The observed bounce‐off from the stage 1 filter is good evidence for weak adhesion of pollen to glass fibre filters.…”

Section: Discussionmentioning

confidence: 99%

Differences in size selective aerosol sampling for pollen allergen detection using high‐volume cascade impactors

Riediker¹,

Koller²,

Monn³

2000

Clin Experimental Allergy

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The observed bounce and blow-off of pollen without a greased stage 2 leads to serious mistakes when assessing the allergen content of the fractions collecting particles smaller than intact pollen, i.e., below 10.2 micrometer. Pollen allergen concentrations in respirable particle fractions are much lower than in the pollen size fraction. This is of great importance both for symptoms of sensitized allergic asthmatics and for research of asthma-related mechanisms.

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Section: Discussionmentioning

confidence: 99%

Differences in size selective aerosol sampling for pollen allergen detection using high‐volume cascade impactors

Riediker¹,

Koller²,

Monn³

2000

Clin Experimental Allergy

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“…An illustration of the preparation of carbon fi lms can be found in an earlier review (27). Sogo et al (52) have examined films of aluminum and beryllium: these may have advantages for very fine structure studies, for routine examination of chromatin; however, carbon appears to be most easily prepared and generally suitable. It has been said to be important to use very thin carbon films to attain the highest contrast between DNA and·its support.…”

Section: Preparation Of Supporting Filmsmentioning

confidence: 98%

“…Treatment 0/ the Supporting Films to Facilitate DNA Binding DNA fibers adhere poorly to the surface of hydrophobic, untreated carbon fi lms.To facilitate binding, the films must be treated or "activated." Sogo et al(52) suggest these treatments operate by applying a charge opposite that of the DNA to the surface of the grid. A common physical approach is to subject the grids to a 1O,OOO -V discharge in an air atmosphere of 200 11m of Hg pressure(27) (glow charging).…”

mentioning

confidence: 99%

Electron Microscope Visualization of Chromatin and Other Dna-Protein Complexes

Griffith¹,

Christiansen²

1978

Annu. Rev. Biophys. Bioeng.

229

132

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In this review we have tried to cover the direct mounting techniques currently in use and, through micrographs kindly supplied by our colleagues, to illustrate uses of the different methods. For the novice, it is important to select one technique, taking time to become acquainted with its use in visualizing simple test samples before applying it to examine more complex structures. We have tried to emphasize the importance of controlling the fixation for two reasons. First, confidence in the fixation step allows one to correlate structures observed by EM with structures present in solution. Second, fixation of otherwise labile samples allows one to apply powerful purification techniques.

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“…A sensitive vibrating plate electrometer was used by Sogo et al (1975) in an attempt to measure directly the surface charge of support films in air. The measurements obtained corresponded well to the characterization of surface charge as inferred from the adsorption of DNA.…”

Section: S U R F a C E -P O T E N T I A L M E A S U R E M E N T S O Nmentioning

confidence: 99%

Interfacial energies and surface‐tension forces involved in the preparation of thin, flat crystals of biological macromolecules for high‐resolution electron microscopy

Glaeser

Zilker

Radermacher

et al. 1991

Journal of Microscopy

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SUMMARY It is generally agreed that surface‐tension forces and the direct interaction between the specimen and either the air‐water interface or the water‐substrate interface can influence significantly the preparation of biological materials for electron microscopy. Even so, there is relatively little systematic information available that would make it possible to control surface‐tension forces and interfacial energies in a quantitative fashion. The main objective in undertaking the present work has been to understand somewhat better the factors that influence the degree of specimen flatness of large, monolayer crystals of biological macromolecules. However, the data obtained in our work should be useful in understanding the preparation of specimens of biological macromolecules in general. Data collection by electron diffraction and electron microscopy at high resolution and high tilt angles requires thin crystals of biological macromolecules that are flat to at least 1°, and perhaps less than 0·2°, over areas as large as 1 μm2 or more. In addition to determining empirically by electron diffraction experiments whether sufficiently flat specimens can be prepared on various types of modified or unmodified carbon support films, we have begun to use other techniques to characterize both the surfaces involved and the interaction of our specimen with these surfaces. In the specific case of large, monolayer crystals of bacteriorhodopsin prepared as glucose‐embedded specimens on hydrophobic carbon films, it was concluded that the initial interfacial interaction involves adsorption of the specimen to the air‐water interface rather than adsorption of the specimen to the substrate. Surface‐tension forces at the air‐water interface and an apparently repulsive interaction between the specimen and the hydrophobic carbon seem to be major factors influencing the specimen flatness in this case. In the more general case it seems likely that interfacial interactions with either the substrate or the air‐water interface can be variously manipulated in the search to find desirable conditions of specimen preparation.

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Adsorption of DNA molecules to different support films

Cited by 22 publications

References 18 publications

Differences in size selective aerosol sampling for pollen allergen detection using high‐volume cascade impactors

Differences in size selective aerosol sampling for pollen allergen detection using high‐volume cascade impactors

Electron Microscope Visualization of Chromatin and Other Dna-Protein Complexes

Interfacial energies and surface‐tension forces involved in the preparation of thin, flat crystals of biological macromolecules for high‐resolution electron microscopy

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