Sample Shrinkage and Radiation Damage

Luther, Pradeep K.

doi:10.1007/978-1-4757-2163-8_3

Cited by 26 publications

(15 citation statements)

References 30 publications

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“…These authors observed that the poly P granules showed evaporation typical of polyphosphate during exposure to high intensity electron beam. The iron contained in the poly P granules could stabilize the granule under the electron beam in the same way that staining with heavy-metal salts enhances the contrast and makes the specimen less sensitive to radiation (Luther, 1992). Bode et al (1993) precised that this phenomenon is dependent on the time of exposure and was not so obvious in smaller granules.…”

Section: Discussionmentioning

confidence: 99%

Elemental characterization of microorganism granules by EFTEM in the tube wall of a deep‐sea vent invertebrate

Lechaire¹,

Shillito²,

Frebourg³

et al. 2002

Biology of the Cell

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Microorganisms colonizing the exoskeletons of the tube worm Riftia pachyptila are described at the ultrastructural level. The prokaryotic cells from the worm tube wall differ from those colonizing the exoskeleton outer surface in the presence of an electron dense granule. The morphology and distribution of these bacteria-like cells are described. Prokaryotic organisms are assembled in nodules which increased in size in the oldest part of the exoskeleton. The aspect, location and elemental composition of the intracellular granules are determined. Most of them (100 nm in diameter) are located close to the cell membrane and exhibit a homogeneous and amorphous content. EDX and EFTEM microanalyses show that these structures contain phosphorus, oxygen and iron. All together these data suggest that these granules are iron polyphosphates. These structures may act as energy sources for making ATP during anoxic conditions as existing in hydrothermal environments.

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Section: Discussionmentioning

confidence: 99%

Elemental characterization of microorganism granules by EFTEM in the tube wall of a deep‐sea vent invertebrate

Lechaire¹,

Shillito²,

Frebourg³

et al. 2002

Biology of the Cell

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“…Typical values are up to 15% in X-Y and 35-40% in 2 (Luther et al, 1988;Luther, 1992). This is of special concern for tomography since sample shrinkage is a critical factor affecting the quality of a given data set.…”

Section: Introductionmentioning

confidence: 99%

Cryo automated electron tomography: Towards high‐resolution reconstructions of plastic‐embedded structures

Braunfeld

Koster

Sedat

et al. 1994

Journal of Microscopy

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Summary The use of fully automated data collection methods for electron tomography allows a substantial reduction in beam dose. The goal has been to develop new protocols for data collection defining optimal approaches for maintaining data self‐consistency and maximizing the useful resolution of the reconstruction. The effects of irradiation and post‐cure microwaving were examined for a variety of embedding media (Epon, Epox, Lowicryl) in order to quantify beam damage with the goal of identifying the most beam stable embedding medium. Surprisingly, the substantial dose reduction made possible by automated data collection did not result in a significant decrease in specimen shrinkage even for samples stabilized by preirradiation. We believe that the accelerated shrinkage is a direct consequence of the stroboscopic illumination patterns inherent to automated data collection. Further‐more neither the choice of embedding resin nor microwave post‐curing greatly affected shrinkage. Finally, cryogenic data collection was investigated as a means to minimize the effects of secondary radiation damage. Minimal preirradiation coupled with low‐temperature automated data collection greatly reduces shrinkage and should result in high‐quality data for three‐dimensional reconstructions.

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“…Even if the analysed element is not removed by the electron beam, mass loss of matrix elements may interfere with the measurement of elemental ratios. It is now well established that radiation damage effects are greatly reduced by TEM at low temperatures (Cosslett, 1978; Luther, 1992; Shillito et al, 1997). This is also the first time that studies of symbiotic associations, thin sections and liquid‐nitrogen cooling are combined.…”

Section: Discussionmentioning

confidence: 99%

In situ localization of sulphur in the thioautotrophic symbiotic model Lucina pectinata (Gmelin, 1791) by cryo‐EFTEM microanalysis

Lechaire

Frebourg

Gaill

et al. 2006

Biology of the Cell

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Background information. Lucina pectinata is a large tropical lucinid known to harbour sulphide‐oxidizing bacteria in specialized gill cells. Conventional TEM (transmission electron microscopy) has shown that bacteriocytes also harbour visibly ‘empty’ vesicles whose chemical content remains, to date, only roughly determined. Results. In the present study, L. pectinata gill tissues were cryo‐fixed as fast as possible by performing high‐pressure freezing before a freeze‐substitution process and finally performing a cryo‐embedding in Lowicryl. Ultrathin sections were then used for a cryo‐EFTEM (where EFTEM stands for energy‐filtered TEM) microanalysis. Results show that bacteriocytes within the gill tissues contain elemental sulphur in small vesicles produced by the host itself. In instances of sporadic depletion of sulphur in the environment, such structures may act as energy sources for bacterial endosymbionts. Conclusions. The cryo‐EFTEM techniques represent (i) the only method used to date to locate and preserve sulphur at the cellular level and (ii) a powerful tool for sulphur metabolism analysis in thioautotrophic symbiont relationships.

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Sample Shrinkage and Radiation Damage

Cited by 26 publications

References 30 publications

Elemental characterization of microorganism granules by EFTEM in the tube wall of a deep‐sea vent invertebrate

Elemental characterization of microorganism granules by EFTEM in the tube wall of a deep‐sea vent invertebrate

Cryo automated electron tomography: Towards high‐resolution reconstructions of plastic‐embedded structures

In situ localization of sulphur in the thioautotrophic symbiotic model Lucina pectinata (Gmelin, 1791) by cryo‐EFTEM microanalysis

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