Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

Author(s):  
P.J. Dailey

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).


Author(s):  
J. C. Russ ◽  
E. McNatt

In order to study the retention of copper in cirrhotic liver, rats were made cirrhotic by carbon tetrachloride inhalation twice weekly for three months and fed 0.2% copper acetate ad libidum in drinking water for one month. The liver tissue was fixed in osmium, sectioned approximately 2000 Å thick, and stained with lead citrate. The section was examined in a scanning electron microscope (JEOLCO JSM-2) in the transmission electron mode.Figure 1 shows a typical area that includes a red blood cell in a sinusoid, a disse, and a portion of the cytoplasm of a hepatocyte which contains several mitochondria, peribiliary dense bodies, glycogen granules, and endoplasmic reticulum.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


Author(s):  
Venita F. Allison ◽  
J. E. Ubelaker ◽  
J. H. Martin

It has been suggested that parasitism results in a reduction of sensory structures which concomitantly reflects a reduction in the complexity of the nervous system. The present study tests this hypothesis by examining the fine morphology and the distribution of sensory receptors for two species of aspidogastrid trematodes by transmission and scanning electron microscopy. The species chosen are an ectoparasite, Cotylaspis insignis and an endoparasite, Aspidogaster conchicola.Aspidogaster conchicola and Cotylaspis insignis were obtained from natural infections of clams, Anodonta corpulenta and Proptera purpurata. The specimens were fixed for transmission electron microscopy in phosphate buffered paraformaldehyde followed by osmic acid in the same buffer, dehydrated in an ascending series of ethanol solutions and embedded in Epon 812.


Author(s):  
J. A. Traquair ◽  
E. G. Kokko

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.


Author(s):  
Thomas P. Turnbull ◽  
W. F. Bowers

Until recently the prime purposes of filters have been to produce clear filtrates or to collect particles from solution and then remove the filter medium and examine the particles by transmission electron microscopy. These filters have not had the best characteristics for scanning electron microscopy due to the size of the pores or the surface topography. Advances in polymer chemistry and membrane technology resulted in membranes whose characteristics make them versatile substrates for many scanning electron microscope applications. These polysulphone type membranes are anisotropic, consisting of a very thin (0.1 to 1.5 μm) dense skin of extremely fine, controlled pore texture upon a much thicker (50 to 250μm), spongy layer of the same polymer. Apparent pore diameters can be controlled in the range of 10 to 40 A. The high flow ultrafilters which we are describing have a surface porosity in the range of 15 to 25 angstrom units (0.0015-0.0025μm).


Author(s):  
John F. Mansfield

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quaity positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).The problem for many researchers, however, is that they have perfectly serviceable microscopes that they routinely use that have no digital imaging capabilities with little hope of purchasing a new instrument.


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