scholarly journals Preparation of viral samples within biocontainment for ultrastructural analysis: Utilization of an innovative processing capsule for negative staining

2016 ◽  
Vol 238 ◽  
pp. 70-76 ◽  
Author(s):  
Mitchell K. Monninger ◽  
Chrystal A. Nguessan ◽  
Candace D. Blancett ◽  
Kathleen A. Kuehl ◽  
Cynthia A. Rossi ◽  
...  
Author(s):  
I. Brent Heath

Detailed ultrastructural analysis of fungal mitotic systems and cytoplasmic microtubules might be expected to contribute to a number of areas of general interest in addition to the direct application to the organisms of study. These areas include possibly fundamental general mechanisms of mitosis; evolution of mitosis; phylogeny of organisms; mechanisms of organelle motility and positioning; characterization of cellular aspects of microtubule properties and polymerization control features. This communication is intended to outline our current research results relating to selected parts of the above questions.Mitosis in the oomycetes Saprolegnia and Thraustotheca has been described previously. These papers described simple kinetochores and showed that the kineto- chores could probably be used as markers for the poorly defined chromosomes. Kineto- chore counts from serially sectioned prophase mitotic nuclei show that kinetochore replication precedes centriole replication to yield a single hemispherical array containing approximately the 4 n number of kinetochore microtubules diverging from the centriole associated "pocket" region of the nuclear envelope (Fig. 1).


Author(s):  
A. C. Reimschuessel ◽  
V. Kramer

Staining techniques can be used for either the identification of different polymers or for the differentiation of specific morphological domains within a given polymer. To reveal morphological features in nylon 6, we choose a technique based upon diffusion of the staining agent into accessible regions of the polymer.When a crystallizable polymer - such as nylon 6 - is cooled from the melt, lamellae form by chainfolding of the crystallizing long chain macromolecules. The regions between adjacent lamellae represent the less ordered amorphous domains into which stain can diffuse. In this process the lamellae will be “outlined” by the dense stain, giving rise to contrast comparable to that obtained by “negative” staining techniques.If the cooling of the polymer melt proceeds relatively slowly - as in molding operations - the lamellae are usually arranged in a radial manner. This morphology is referred to as spherulitic.


Author(s):  
Gerald Rupp

The marine protozoan Allogromia sp, strain NF Lee extends an elaborate reticulopodial network (RN) which contains an elongate microtubule-(MT)-based cytoskeleton. The MTs are located primarily within cytoplasmic fibrils which are visible by light microscopy (LM) in highly flattened or “two dimensionalized” reticulopodia. It was shown previously that allogromiid RNs withdraw in response to hypertonic Mg2+-seawater. An ultrastructural analysis of this phenomenon indicated that large patches of paracrystalline (PC) material, composed of helical filament aggregates, form concomitant with a decrease in MT number. Similar large patches of PC aggregates are also found in juvenile Allogromia before they extend a RN, which disappear during RN formation. Finally, PC aggregates are occasionally seen near microtubules in normal untreated RNs. Thus there is circumstantial evidence to propose that PC aggregates in Allogromia represent an intermediate form of tubulin; however, more definitive biochemical or immunocytochemical data is not available.


Author(s):  
S. F. Hayes ◽  
M. D. Corwin ◽  
T. G. Schwan ◽  
D. W. Dorward ◽  
W. Burgdorfer

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.


1997 ◽  
Vol 3 (S2) ◽  
pp. 341-342
Author(s):  
Sara E. Miller

Negative staining is the most frequently used procedure for preparing particulate specimens, e.g., cell organelles, macromolecules, and viruses, for electron microscopy (Figs. 1-4). The main advantage is that it is rapid, requiring only minutes of preparation time. Another is that it avoids some of the harsh chemicals, e.g., organic solvents, used in thin sectioning. Also, it does not require advanced technical skill. It is widely used in virology, both in classification of viruses as well as diagnosis of viral diseases. Notwithstanding the necessity for fairly high particle counts, virus identification by negative staining is advantageous in not requiring specific reagents such as antibodies, nucleic acid probes, or protein standards which necessitate prior knowledge of potential pathogens for selection of the proper reagent. Furthermore, it does not require viable virions as does growth in tissue culture. Another procedure that uses negative contrasting is ultrathin cryosectioning (Fig. 5).In 1954 Farrant was the first to publish negatively stained material, ferritin particles.


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