Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

1956 ◽  
Vol 2 (4) ◽  
pp. 305-312 ◽  
Author(s):  
E. W. Dempsey

A characteristic internal structure, consisting of a double-layered outer wall enclosing a matrix-filled space through which pass double-layered membranous folds, would appear to comprise as satisfactory a definition of mitochondria for electron microscopy as their intravital affinity for Janus green affords for light microscopy. Relying for identification upon this characteristic internal structure, mitochondria appear to be pleomorphic structures which vary in size, shape, complexity, and density. They are labile also in that their number may increase or decrease under controlled conditions. The possibility therefore exists that these organelles are constantly being formed and destroyed, perhaps by their participation in metabolic processes. The problem of the origin of mitochondria is in an unsatisfactory state. New organelles unquestionably are formed in particular physiological states. The possibility that new bodies are produced by fission of ones already present does not seem adequate. On the other hand, the possible fabrication of new mitochondria out of intracellular membranes, although an attractive hypothesis, has not been adequately substantiated.


1994 ◽  
Vol 6 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Marek R. Lipinski ◽  
M. Deon Durholtz

It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.


Phytotaxa ◽  
2015 ◽  
Vol 207 (1) ◽  
pp. 135 ◽  
Author(s):  
Giovanni Raul Bogota ◽  
Carina Hoorn ◽  
Wim Star ◽  
Rob Langelaan ◽  
Hannah Banks ◽  
...  

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera. 


1988 ◽  
Vol 66 (5) ◽  
pp. 829-838 ◽  
Author(s):  
M. J. Hodson ◽  
A. G. Sangster

Silica deposition in the lower glume, lemma, and palea of wheat (Triticum aestivum L. cv. Highbury) was investigated using scanning electron microscopy and light microscopy. Silica was present in the outer walls of all the epidermal cells including prickles and papillae of the glume and lemma awns. The glume and the lemma were similar in epidermal silica deposition pattern, both having numerous silicified short trichomes and papillae on inner and outer surfaces. Epidermal long cells and short cells were also silicified. Macrohairs were restricted to isolated areas in these bracts, particularly on the inner surfaces just beneath the awns. The palea was a thin membranous structure differing markedly from the other two bracts. Most of the palea is pressed between the caryopsis and the next floret, and both surfaces are almost devoid of trichomes in these areas. However, at the apex and margins of the palea, macrohairs and papillae were abundant. The results are discussed with respect to possible taxonomic, anatomical, medical, and archaeological implications.


2004 ◽  
Vol 165 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Karen R. Dell ◽  
Ronald D. Vale

The 2003 International Prize for Biology was awarded to Shinya Inoue for his pioneering work in visualizing dynamic processes within living cells using the light microscope. He and his scientific descendants are now pushing light microscopy even further by developing new techniques such as imaging single molecules, visualizing processes in living animals, and correlating results from light and electron microscopy.


1976 ◽  
Vol 24 (8) ◽  
pp. 948-955 ◽  
Author(s):  
P E McKeever ◽  
A J Garvin ◽  
S S Spicer

A method is described for ultrastructural localization of immune complex receptors on the surface of viable peritoneal exudate cells. The technique entails incubation with a soluble complex of horseradish peroxidase (HRP) and specific antibody to HRP at 4 degrees C followed by exposure to diaminobenzidine and processing for electron microscopy. The bound immune complexes were evident as focal deposits of HRP reaction product, adhering closely to the external surface of macrophages with an uninterrupted periodicity varying between 30 and 120 nm. Following incubation with an insoluble immune complex containing a higher proportion of antibody, receptor sites stained frequently, but large aggregates adhered to the cells. Rinsing cells after staining with soluble complexes partially displaced the bound immune complexes. Fixation prior to exposure to immune complexes largely eliminated the binding capacity of the immune complex receptors.


1981 ◽  
Vol 64 (1) ◽  
pp. 199-224
Author(s):  
John E Kvenberg

Abstract Larval stored product beetle mandibles were studied by comparing images made by scanning electron microscopy with those made by conventional light microscopy. Discussion of morphological characteristics is based on illustrations of 25 species


Author(s):  
Edwin S. Boatman

The effect of acridine derivatives on bacterial growth has been shown to be dependent upon the concentration used, pH, temperature, and the position of the amino substituents on the acridine molecule. These factors, in turn, affect the amount of acridine bound to cell constituents. Many bacterial species, when grown in media containing acridities, become filamentous, or pleomorphic, or growth may be entirely prevented. The fine-structure of two species of bacteria treated with acriflavine was investigated. Both were Gram-positive bacilli, one was a Corynebacterium, and the other an aerobic spore-bearing Bacillus.Organisms were incubated at 21°c in the presence of concentrations of acriflavine ranging from 0.25 ug/ml to 12 ug/ml in phosphate buffered peptone water yeast extract medium at pH 7.5. Viable counts were carried out and the amount of acriflavine bound, either reversibly or irreversibly, was estimated at 450 mu, using a DB spectrophotometer. Cultures were observed by light microscopy and, after four days growth, were processed for electron microscopy by fixation in veronal-acetate pH 6.1 buffered 0.8% Os O4 for one hour and embedding in Epon 812 resin.


1969 ◽  
Vol 4 (1) ◽  
pp. 3-15
Author(s):  
E. G. JORDAN ◽  
M. B. E. GODWARD

Several species of Spirogyra have been collected and fixed for electron microscopy in either 2% osmium tetroxide or 5% glutaraldehyde. Mitotic cells were selected with the light microscope from filaments of Spirogyra embedded in Epon. Evidence is given for an interphase cycle in the nucleolus of Spirogyra. A clear association between nucleolar material and chromosomes occurs at mitosis. The breakdown of the nucleolus is shown to occur in two stages, one as a consequence of the withdrawal of the nucleolar chromosomes, and the other after telophase in the new nucleus. The significance of these findings is discussed.


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