The role of scanning electron microscopy in cell and molecular biology:

Schatten, Heide

doi:10.1017/cbo9781139018173.002

Cited by 5 publications

(7 citation statements)

References 47 publications

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“…After two washes (1 h each) with deionized water, tissues were dehydrated in an ethanol series and critical point dried using a Samdri-780 ® (TOUSIMIS Research Corporation, Rockville, USA). We coated the samples with gold:palladium (80%:20%) in a JFC-1100 (Fine coat ion sputter JFC-1100, JEOL Ltd., Tokyo, Japan) and observed them with a SEM microscope (JSM 6390 JEOL, Japan) working at 15 kv [ 91 ]. We documented the procedure digitally [ 92 ].…”

Section: Methodsmentioning

confidence: 99%

First description of extrafloral nectaries in Opuntia robusta (Cactaceae): Anatomy and ultrastructure

et al. 2018

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To our knowledge, there are no studies about the structure and ecological function of extrafloral nectaries (EFNs) in Opuntia robusta. This is the first description of EFNs in O. robusta, where young spines have an interesting structure and a secreting function, which are different from EFNs described in other Cactaceae species. We used light, scanning-electron, and transmission-electron microscopy to examine morphology, anatomy, and ultrastructure of the secretory spines in areoles in female and hermaphrodite individuals of O. robusta. Young cladodes develop areoles with modified and secretory spines as EFNs only active during the early growth phase. EFNs are non-vascularized structures, with no stomata, that consist of a basal meristematic tissue, a middle elongation region, and an apical secretory cone formed by large globular epidermal cells, containing nectar and medullar elongated cells. We observed the presence of Golgi apparatus, vesicles and plastids in the medullar and sup-epidermal cells of the spine. We propose that the nectar is stored in the globular cells at the apex of the spine and secreted by breaking through the globular cells or by pores. We recorded a more frequent presence of ants on younger cladode sprouts producing young secreting spines: this result is parallel with the predictions of Optimal Defense Hypothesis, which states that younger plant organs should be better defended than older ones because their loss produces a higher fitness impairment. Although Diaz-Castelazo’s hypothesis states that a more complex structure of EFNs correlates with their lower among-organs dispersion, comparing to less complex EFNs, non-vascularized structure of EFNs in O. robusta is not associated with their higher among-organs dispersion likened to O. stricta, which produces vascularized EFNs. We provide evidence that this characteristic is not a good taxonomic feature of Opuntia genus. Moreover, the comparison of EFNs of O. robusta and O. stricta suggests that the hypothesis of Diaz-Castelazo should be revised: it is rather a rule but not a law.

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Section: Methodsmentioning

confidence: 99%

First description of extrafloral nectaries in Opuntia robusta (Cactaceae): Anatomy and ultrastructure

et al. 2018

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“…In scanning electron microscopy (SEM), a focused beam of electrons is rastered across the sample. Electrons that bounce back from the surface are used to generate an image that provides topographical information on the sample [19]. In TEM, images are formed from electrons that are passed through and interact with the sample.…”

Section: Em Modalities and Conventional Em Sample Preparationmentioning

confidence: 99%

Looking back and looking forward: contributions of electron microscopy to the structural cell biology of gametes and fertilization

2020

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Mammalian gametes—the sperm and the egg—represent opposite extremes of cellular organization and scale. Studying the ultrastructure of gametes is crucial to understanding their interactions, and how to manipulate them in order to either encourage or prevent their union. Here, we survey the prominent electron microscopy (EM) techniques, with an emphasis on considerations for applying them to study mammalian gametes. We review how conventional EM has provided significant insight into gamete ultrastructure, but also how the harsh sample preparation methods required preclude understanding at a truly molecular level. We present recent advancements in cryo-electron tomography that provide an opportunity to image cells in a near-native state and at unprecedented levels of detail. New and emerging cellular EM techniques are poised to rekindle exploration of fundamental questions in mammalian reproduction, especially phenomena that involve complex membrane remodelling and protein reorganization. These methods will also allow novel lines of enquiry into problems of practical significance, such as investigating unexplained causes of human infertility and improving assisted reproductive technologies for biodiversity conservation.

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“…Visualising structures of cells and tissue by the scanning electron microscope (SEM) has been a great help in understanding many processes studied by Life Sciences (Schatten, 2012). A common challenge in cell biology, botany and medical applications is the hydrated nature of the sample, which is incompatible with the vacuum conditions required for high-end SEM imaging.…”

Section: Introductionmentioning

confidence: 99%

“…A common challenge in cell biology, botany and medical applications is the hydrated nature of the sample, which is incompatible with the vacuum conditions required for high-end SEM imaging. Two general solutions are available: (1) extracting the water, optionally being replaced by a resin and (2) cryo-fixate the hydrated sample and maintain the frozen condition in the SEM (Schatten, 2012). Note that cryo-fixation is also used in processes of extracting and/or replacing the water phase (e.g.…”

Section: Introductionmentioning

confidence: 99%

An introduction to cryo‐FIB‐SEM cross‐sectioning of frozen, hydrated Life Science samples

Hayles¹,

Winter

2020

Journal of Microscopy

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The introduction of cryo-techniques to the focused ion-beam scanning electron microscope (FIB-SEM) has brought new opportunities to study frozen, hydrated samples from the field of Life Sciences. Cryo-techniques have long been employed in electron microscopy. Thin electron transparent sections are produced by cryo-ultramicrotomy for observation in a cryo-transmission electron microscope (TEM). Cryo-TEM is presently reaching the imaging of macromolecular structures. In parallel, cryo-fractured surfaces from bulk materials have been investigated by cryo-SEM. Both cryo-TEM and cryo-SEM have provided a wealth of information, despite being 2D techniques. Cryo-TEM tomography does provide 3D information, but the thickness of the volume has a maximum of 200-300 nm, which limits the 3D information within the context of specific structures. FIB-milling enables imaging additional planes by creating cross-sections (e.g. cross-sectioning or site-specific X-sectioning) perpendicular to the cryo-fracture surface, thus adding a third imaging dimension to the cryo-SEM. This paper discusses how to produce suitable cryo-FIB-SEM cross-section results from frozen, hydrated Life Science samples with emphasis on 'common knowledge' and reoccurring observations.

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The role of scanning electron microscopy in cell and molecular biology:

Cited by 5 publications

References 47 publications

First description of extrafloral nectaries in Opuntia robusta (Cactaceae): Anatomy and ultrastructure

First description of extrafloral nectaries in Opuntia robusta (Cactaceae): Anatomy and ultrastructure

Looking back and looking forward: contributions of electron microscopy to the structural cell biology of gametes and fertilization

An introduction to cryo‐FIB‐SEM cross‐sectioning of frozen, hydrated Life Science samples

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