Ultrastructure and morphogenesis of the synnema of Ceratocystis ulmi

1973 ◽  
Vol 51 (9) ◽  
pp. 1565-1571 ◽  
Author(s):  
James L. Harris ◽  
Willard A. Taber

Ceratocystis ulmi, the Ascomycete responsible for Dutch elm disease, may sporulate by means of a distinctive structure, the synnema, common in nature in the tunnels of elm bark beetles. Developmental stages of this structure and its spores were examined by light microscopy, by conventional transmission electron microscopy of thin sections and freeze-etch replicas, and by scanning electron microscopy of whole spores and fruiting structures. The synnema is a tight bundle of darkly pigmented hyphae growing erect from the substrate and terminated by a mass of colorless, wet spores. A layer of slime covering the hyphal bundle and random cross-connections between parallel hyphae appear to function in stabilization of the structure. Organelles typical of Ascomycetes fill the spores, vegetative hyphae, and young synnemal hyphae. However, in mature synnemal hyphae, the cytoplasmic contents degenerate, leaving only membranous vesicles in the partially collapsed hyphae. The spores contain large lipid droplets not found in either vegetative or synnemal hyphae indicating some differences in metabolism of spores and hyphae. Most synnemal spores form on sympodulae, but some spores form on intrahyphal hyphae.

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).


2000 ◽  
Vol 6 (S2) ◽  
pp. 872-873
Author(s):  
James R. Rosowski ◽  
Terry L. Bartels ◽  
James F. Colburn ◽  
Jannell L. Colton ◽  
Denton Belk ◽  
...  

Tadpole shrimp inhabit temporary freshwater pools and ponds where their occurrence is largely regulated by rainfall events and water temperature. When dry basins are flooded, cysts of Triops imbibe water and hatch to produce rapidly growing, carapaced larvae. While previous studies show anostracan (fairy shrimp) cyst-surface morphology often species specific, few studies illustrate shell ultrastructure of Triops and none has considered T. longicaudatus. Here we examine the shell of T. longicaudatus (Notostraca) and compare its fine structure to other species of Triops and to that of Artemiafranciscana(Anostraca), which we previously studied.Cysts, produced in culture from Utah broodstock, were purchased from Triops, Inc., 1924 Creighton Rd., Pensacola, FL 32504. Thin sections of cysts were prepared for transmission electron microscopy (TEM) as previously described (Fig. 1). Cysts were also examined with scanning electron microscopy (SEM), dry, whole or fractured (Figs. 2,3), or after imbibition and/or hatching in oxygen saturated, double-distilled water, at 25 ° C.


2003 ◽  
Vol 88 (4) ◽  
pp. 1903-1906 ◽  
Author(s):  
Alessandro Riva ◽  
Felice Loffredo ◽  
Alessandro Uccheddu ◽  
Francesca Testa Riva ◽  
Bernard Tandler

By taking advantage of a modified osmium maceration technique, we have been able to examine by high resolution scanning electron microscopy (HRSEM) the interior of human adrenocortical mitochondria from which all soluble material has been extracted. The so-called vesicles apparent in thin sections examined by transmission electron microscopy actually are finger-like cristae as determined by HRSEM. These digitiform cristae have a segmented appearance and a bulbous tip. The segmented form of the cristae may have important metabolic implications.


1977 ◽  
Vol 25 (4) ◽  
pp. 295-305 ◽  
Author(s):  
M Horisberger ◽  
J Rosset

Electron dense markers of a size suitable for transmission electron microscopy and scanning electron microscopy have been prepared with gold granules labeled with a monolayer of specific macromolecules. The optimum conditions for preparing the markers have been ascertained. The method is simple, rapid and seems to be general since gold granules have been labeled with polysaccharides and proteins. As homogeneous populations of gold granules having different sizes can be prepared, the method is also suitable for double marking experiments. The gold technique is illustrated by the localization of polysaccharides and glycoproteins on yeast cell walls and erythrocyte membranes by transmission electron microscopy and on yeast cells and intact erythrocytes by scanning electron microscopy. Good spatial resolution of the marker was achieved in all cases. The method is also suitable for marking thin sections. Spectrophotometric measurements were used to determine the number of gold granules adsorbed per cell.


1978 ◽  
Vol 56 (7) ◽  
pp. 747-753 ◽  
Author(s):  
P. Jeffries ◽  
T. W. K. Young

Using results obtained with light and scanning electron microscopy of critical-point-dried material and transmission electron microscopy of carbon replicas and freeze-fracture and ultra-thin sections, the structure and germination of the sporangiospore of Phascolomyces articulosus Boedijn is described. The sporangial wall is trilaminate and the ornamented spore wall is two layered. During germination, a new wall layer develops between the plasmalemma and the original spore wall. Sporangial structure is related to that of other members of the Thamnidiaceae and the use of germinating spores of P. articulosus for infection studies of the mycoparasite Piptocephalis unispora is indicated.


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):  
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. D. Hutchison

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.


Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.


Author(s):  
J. Temple Black

Since its introduction by Fernandez-Moran, the diamond knife has gained wide spread usage as a common material for cutting of thin sections of biological and metallic materials into thin films for examination in the transmission electron microscope. With the development of high voltage E.M. and scanning transmission E.M., microtomy applications will become increasingly important in the preparation of specimens. For those who can afford it, the diamond knife will thus continue to be an important tool to accomplish this effort until a cheaper but equally strong and sharp tool is found to replace the diamond, glass not withstanding.In Figs. 1 thru 3, a first attempt was made to examine the edge of a used (β=45°) diamond knife by means of the scanning electron microscope. Because diamond is conductive, first examination was tried without any coating of the diamond. However, the contamination at the edge caused severe charging during imaging. Next, a thin layer of carbon was deposited but charging was still extensive at high magnification - high voltage settings. Finally, the knife was given a light coating of gold-palladium which eliminated the charging and allowed high magnification micrographs to be made with reasonable resolution.


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