Scanning Electron Microscopic Studies on the Tegument of Trematodes

Author(s):  
J. E. Ubelaker ◽  
R. D. Specian ◽  
V. F. Allison

Among the parasitic flatworms, only members of the trematoda have exploited nearly every conceivable niche. Since physiological demands in each habitat present special problems in eluding the host response as well as obtaining nourishment the surface epithelia of such organisms warrant special attention. To gain an appreciation of tegumental diversity in the trematoda, representative trematodes from numerous habitats in their respective hosts were examined by scanning electron microscopySpecimens were collected from natural infections, fixed in paraformaldehyde and dehydrated in alcohol. Ethanol was exchanged with amyl acetate prior to CO2 drying in a Denton DCP-1 critical point dryer. The dried specimens were mounted on metal holders, outgassed and rotary coated with gold-palladium. These were then examined with the ISI Mini-SEM and AMR 1000 scanning electron microscopes.

1993 ◽  
Vol 71 (9) ◽  
pp. 1855-1860
Author(s):  
Thomas G. Rand

Trichodina labrisomi n.sp. from the gills of the hairy blenny, Labrisomas nuchipinnis (Quoy and Gaimard), in Mangrove Lake, Bermuda, is described using light microscopy and scanning electron microscopy (SEM). Light microscopy reveals that the dimensions and morphology of T. labrisomi are similar to those given for only 13 previously described species of Trichodina (T. acuta Lom, 1961; T. baicalensis Dogiel, 1957; T. cottomephori Stein, 1979; T. dalli Zhukov, 1964; Trichodina domerguei domerguei Lom and Shtein 1966; T. elegans Stein, 1979; T. fultoni Davis, 1947; T. jadranica Haider, 1964; T. jadranica noblei Lom, 1970; T. partidisci Haider, 1964; T. reticulata Hirschmann et Partsch, 1955; T. tenuidens Faure-Fremiet, 1943; and T. tenuiformis Stein, 1979). However, compared with these similar forms, T. labrisomi n.sp. is distinguished by the dimensions of its body and denticulate ring and (or) the appearance of its silver-impregnated adhesive disc and denticles. Features of T. labrisomi examined by SEM include the body shape, pellicle, aboral pellicular pores, border membrane, aboral ciliary complex, and adoral ciliature, which are described and compared with those of other trichodinids studied using SEM. SEM also revealed that bacilli were distributed circumequatorially over the oral surface of T. labrisomi.


1981 ◽  
Vol 59 (2) ◽  
pp. 122-128 ◽  
Author(s):  
G. Deml ◽  
M. Nebel ◽  
F. Oberwinkler

The development of sori, sporogenesis, and characteristics of the hyphae in Ustilago pustulata and U. scabiosae have been investigated by light and scanning electron microscopy. The septa of both species form clamp connections. In U. scabiosae the sporogenous cells are comparable with budding mycelia. The teliospores of Ustilago pustulata and U. scabiosae are formed endogenously in chains.


Author(s):  
Peter M. Andrews

Although there have been a number of recent scanning electron microscopic reports on the renal glomerulus, the advantages of scanning electron microscopy have not yet been applied to a systematic study of the uriniferous tubules. In the present investigation, scanning electron microscopy was used to study the ultrastructural morphology of the proximal, distal, thin loop, and collecting tubules. Material for observation was taken from rat kidneys which were fixed by vascular perfusion, sectioned by either cutting or fracturing technigues, and critically point dried.The brush border characterising proximal tubules is first detected on the luminal surface of Bowman's capsule adjacent to the urinary pole orifice. In this region one frequently finds irregular microvilli characterized by broad and flattened bases with occasional bulbous structures protruding from their surfaces.


1997 ◽  
Vol 3 (S2) ◽  
pp. 1193-1194
Author(s):  
Brendan J. Griffin

Most scanning electron microscopy is performed at low magnification; applications utilising the large depth of field nature of the SEM image rather than the high resolution aspect. Some environmental SEMs have a particular limitation in that the field of view is restricted by a pressure limiting aperture (PLA) at the beam entry point of the specimen chamber. With the original ElectroScan design, the E-3 model ESEM utilised a 500 urn aperture which gave a very limited field of view (∼550um diameter at a 10mm working distance [WD]). An increase of aperture size to ∼lmm provided an improved but still unsatisfactory field of view. The simplest option to increase the field of view in an ESEM was noted to be a movement of the pressure and field, limiting aperture back towards the scan coils1. This approach increased the field of view to ∼2mm, at a 10mm WD. A commercial low magnification device extended this concept and indicated the attainment of conventional fields of view.


1980 ◽  
Vol 88 (3) ◽  
pp. 252-256 ◽  
Author(s):  
Douglas E. Mattox

The single most important factor determining the patency of a microvascular anastomosis is the surgical precision with which it is performed. Inaccurately placed sutures, damage of the intima, exposed media and adventitia, and stenosis of the lumen at the site anastomosis all contribute to decreased patency rates. The first 50 consecutive microvascular anastomoses performed by a single microvascular surgeon were analyzed in vivo and with the scanning electron microscope. The frequency and significance of various technical errors are discussed. Scanning electron microscopy is recommended as a convenient and quick technique for assessing the evenness and accuracy of intimal apposition in microvascular anastomosis.


HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Hirofumi Terai ◽  
Alley E. Watada ◽  
Charles A. Murphy ◽  
William P. Wergin

Structural changes in chloroplasts of broccoli (Brassica oleracea L., Italica group) florets during senescence were examined using light microscopy, scanning electron microscopy (SEM) with freeze-fracture technique, and transmission electron microscopy (TEM) to better understand the process of chloroplast degradation, particularly at the advanced stage of senescence. Light microscopy revealed that chloroplasts, which initially were intact and green, became obscure in shape, and their color faded during senescence. Small, colored particles appeared in cells as the florets approached the final stage of senescence and became full- to dark-yellow in color. Scanning electron microscopy showed that stroma thylakoids in the chloroplast initially were parallel to each other and grana thylakoids were tightly stacked. As senescence advanced, the grana thylakoids degenerated and formed globules. The globules became larger by aggregation as senescence progressed, and the large globules, called “thylakoid plexus,” formed numerous vesicles. The vesicles ultimately were expelled into the cytosol, and the light microscope revealed many colored particles in the senescent cells. These results indicate that the degradation of chloroplasts in broccoli florets progresses systematically, with the final product being colored particles, which are visible in yellow broccoli sepal cells.


2002 ◽  
Vol 116 (6) ◽  
pp. 420-425 ◽  
Author(s):  
J. Skladzień ◽  
J. A. Litwin ◽  
M. Nowogrodzka-Zagórska ◽  
A. J. Miodoński

Surfaces of aural polyps collected from 30 patients were examined by scanning electron microscopy. In the polyps not associated with cholesteatoma, the epithelial lining showed individually variable metaplasia towards cuboidal ‘cobblestone’-type and squamous epithelium covered with microvilli of various shapes and sizes. Squamous epithelium was present on the surface of all polyps with underlying cholesteatoma, with superficial cells possessing elongated microvilli, microplicae of different sizes, grooves and pits. Such surface structures reflect different stages of the keratinization process that seems to becharacteristic for the epithelial lining of polyps with underlying cholesteatoma. Incomplete epithelium accompanied by granulation tissue was found in several polyps; in two cholesteatoma-associated polyps plate-likecholesterol crystals were observed.


1989 ◽  
Vol 26 (3) ◽  
pp. 209-215 ◽  
Author(s):  
U. Kierdorf ◽  
H. Kierdorf

Scanning electron microscopy of surface enamel lesions in fluorosed permanent premolars and molars of free-ranging Roe deer revealed two types of pits. Post-eruptive lesions that resulted from mechanical stress on hypomineralized enamel during mastication were characterized by steep walls and a typical honeycomb structure on their bottom, a result of fracture of enamel rods; holes left by fractured rods were surrounded by interred enamel. Pits of developmental origin (hypoplasias), either as shallow depressions of enamel surfaces or narrow holes running deep into the enamel, were characterized by convex, rounded walls covered by numerous Tomes' process pits. Pits of hypoplastic and post-eruptive origin were often found in the same tooth. Intact enamel surfaces of fluorosed teeth resembled that of controls.


Author(s):  
S. Panem ◽  
P.S.D. Lin ◽  
A. V. Crewe ◽  
W. H. Kirsten

Although oncornaviruses have been the subject of numerous transmission electron microscopic studies, questions concerning virion structure and the maturation of virus at the infected cell membrane remain unanswered. We have begun to study viral morphogenesis with particular emphasis on the distribution of viral budding sites and the appearance of virus during maturation using scanning electron microscopy.


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