PRE-MEETING SHORT COURSES: JULY 31

2005 ◽  
Vol 11 (I1) ◽  
pp. 23-26

Organizers: John Mansfield and Louis KerrAdditional fees required.SC01: Towards Nanoscale Imaging of Anything in VPSEM (including ESEM): From Basics to Current Practices. Full Day: 9:00 AM–5:00 PM, Room 317A.SC02: Image Processing and Analysis. Full Day: 9:00 AM–5:00 PM, Room 317B.SC03: Photoshop for Microscopy and Microanalysis. Full Day: 9:00 AM–5:00 PM, Room 318A.SC04: High Pressure Freezing Cryosectioning of Vitrified Samples for Tomography, and Freeze Substitution. Full Day: 9:00 AM–5:00 PM, Room 318B.SC05: Specimen Preparation for the Physical Sciences. Full Day: 9:00 AM–5:00 PM, Room 319A.SC06: Digital Microscopy and Image Analysis for Materials Characterization. Half Day: 9:00 AM–1:00 PM, Room 319B.SC07: Interpretation of Microstructure. Half-Day: 9:00 AM–1:00 PM, Room 323A.Special Events: Presidential happenings; IMS Henry Clifton Sorby award and lecture; and Art Exhibit.Educational Venues: Microscopic explorations: A workshop; and It's a Family Affair!

2006 ◽  
Vol 12 (S1) ◽  
pp. 26-28

X-11: Scanning Cathodoluminescence Microscopy and Spectroscopy, Full Day: 9:00 AM–5:00 PM, Room 301/303.X-12: Digital Imaging 101: Scientific Imaging with Photoshop, Full day: 9:00 AM–5:00 PM, Room 302/304.X-13: Digital Imaging 102: Image Processing and Analysis, Full Day: 9:00 AM–5:00 PM, Room 306.X-14: Live Cell Imaging Using Fluorescence Methods, Full Day: 9:00 AM–5:00 PM, Room 305.X-15: What To Do with a Variable Pressure (VPSEM) or Environmental SEM (ESEM) And How To Do It (Or At Least How It Ought To Work), Full Day: 9:00 AM–5:00 PM, Room 307.X-16: 3-Dimensional Electron Microscopy (3DEM) in Life and Material Science—In-Depth Tutorial about Tomography—Basics and Methods, Full day: 9:00 AM–5:00 PM, Room 308.X-17 Failure Analysis and Evidence Preservation by Metallography, Half day: 9:00 AM–1:00 PM, Room 309/311.Special events: MSA and MAS presidential happenings, IMS Henry Clifton Sorby award and lecture, and art exhibit.


Author(s):  
J.Z. Kiss ◽  
L.A. Staehelin

Electron microscopy of chemically fixed plant tissues has lead to important insights into the relationship between structure and function of plant cells. However, the slow rate of chemical fixation (seconds to minutes) potentially permits numerous artifacts to be induced. Most of these limitations ofs chemical fixatives can be overcome by the use of cryofixation techniques since cell structure is stabilized rapidly (milliseconds). Several types of cryofixation techniques have been developed such as cold metal block freezing and propane jet freezing. Although application of these techniques has yielded exciting new information, they are limiting in that specimens can be preserved only to a relatively shallow depth (approx. 40 μm). In contrast, under optimal conditions, high pressure freezing (HPF) at 2100 bar can produce excellent freezing of biological samples up to 600 μm in thickness. Since a commercial HPF apparatus has only recently become available, the number of systematic structural studies of biological samples utilizing HPF is still rather limited, and basic questions concerning specimen preparation and processing, HPF artifacts, and interpretation of images need to be addressed.


Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.


Author(s):  
William P. Sharp ◽  
Robert W. Roberson

The aim of ultrastructural investigation is to analyze cell architecture and relate a functional role(s) to cell components. It is known that aqueous chemical fixation requires seconds to minutes to penetrate and stabilize cell structure which may result in structural artifacts. The use of ultralow temperatures to fix and prepare specimens, however, leads to a much improved preservation of the cell’s living state. A critical limitation of conventional cryofixation methods (i.e., propane-jet freezing, cold-metal slamming, plunge-freezing) is that only a 10 to 40 μm thick surface layer of cells can be frozen without distorting ice crystal formation. This problem can be allayed by freezing samples under about 2100 bar of hydrostatic pressure which suppresses the formation of ice nuclei and their rate of growth. Thus, 0.6 mm thick samples with a total volume of 1 mm3 can be frozen without ice crystal damage. The purpose of this study is to describe the cellular details and identify potential artifacts in root tissue of barley (Hordeum vulgari L.) and leaf tissue of brome grass (Bromus mollis L.) fixed and prepared by high-pressure freezing (HPF) and freeze substitution (FS) techniques.


Author(s):  
Robert W. Roberson

The use of cryo-techniques for the preparation of biological specimens in electron microscopy has led to superior preservation of ultrastructural detail. Although these techniques have obvious advantages, a critical limitation is that only 10-40 μm thick cells and tissue layers can be frozen without the formation of distorting ice crystals. However, thicker samples (600 μm) may be frozen well by rapid freezing under high-pressure (2,100 bar). To date, most work using cryo-techniques on fungi have been confined to examining small, thin-walled structures. High-pressure freezing and freeze substitution are used here to analysis pre-germination stages of specialized, sexual spores (teliospores) of the plant pathogenic fungus Gymnosporangium clavipes C & P.Dormant teliospores were incubated in drops of water at room temperature (25°C) to break dormancy and stimulate germination. Spores were collected at approximately 30 min intervals after hydration so that early cytological changes associated with spore germination could be monitored. Prior to high-pressure freezing, the samples were incubated for 5-10 min in a 20% dextran solution for added cryoprotection during freezing. Forty to 50 spores were placed in specimen cups and holders and immediately frozen at high pressure using the Balzers HPM 010 apparatus.


1998 ◽  
Vol 4 (S2) ◽  
pp. 1134-1135
Author(s):  
Y. Wang ◽  
B. A. Wustman ◽  
Y. Chen ◽  
C. Lavin ◽  
M. R. Gretz

An integrated approach including TEM, SEM and LM was utilized to investigate adhesives produced by the marine fouling diatom Achnanthes longipes. Extracellular adhesive secretion during sequential attachment in living diatom cells was examined using video microscopy. A suite of cryotechniques including high pressure freezing (HPF), freeze-substitution (FS) and high resolution cryo-field-emission SEM (cryo-FESEM) were required for preservation and structural investigation of the hydrophilic polymers synthesized by A. longipes that promote attachment to ship hulls, oil rigs and other submerged structures.Living cells and associated extracellular biocomposites were rapidly cryo-immoblized and observed using a Hitachi S-900 FESEM equipped with a cryo-stage. This technique allowed resolution of details of polymer organization within the pad, shaft and collar portions of the major adhesive structure termed a stalk (Fig. 1,2). This stalk has been demonstrated to consist mainly of polysaccharide cross-linked by O-linked polypeptides. In addition to permanently adhering the diatom to the substratum, the stalk elevates A. longipes, possibly enhancing the ability to successfully compete with other biofilm dwellers.


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