Scanning electron microscopy of the digestive tract of larval Simulium ornatum Meigen (Complex) (Diptera: Simuliidae) and its associated microbial flora

1995 ◽  
Vol 73 (9) ◽  
pp. 1640-1646 ◽  
Author(s):  
Mark R. Taylor ◽  
Stephen T. Moss ◽  
Mike Ladle
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digestive Tract ◽  
Freeze Fracture ◽  
Microbial Flora ◽  
Peritrophic Membrane ◽  
Filamentous Bacteria ◽  
Direct Observations ◽  
Dissection Technique ◽  
Scanning Electron

The structure and microbial flora of the digestive tract of larval Simulium ornatum were investigated using scanning electron microscopy. Direct observations of the microbial communities associated with the endoperitrophic surface of the peritrophic membrane and the endocuticular surface of the hindgut are presented. The endoperitrophic surface was frequently devoid of bacteria, although the fungus Harpella melusinae (Harpellales, Trichomycetes) was commonly attached. Rarely, spirochaetes and coccoid bacteria were attached to the endoperitrophic surface. In contrast, the endocuticular surface was regularly colonized by a diverse microflora composed of rod-shaped, coccoid, spiral, and filamentous bacteria and two species of Harpellales (Trichomycetes). A freeze-fracture technique is compared with a dissection technique for exposing the endoperitrophic and endocuticular surfaces of the digestive tract.

Ultrastructural Features of Normal and Diseased Hair Revealed by Ion Beam Etching and Freeze Fracture

1975 ◽  
Vol 33 ◽  
pp. 358-359
Author(s):  
M. Spector ◽  
A. C. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ectodermal Dysplasia ◽  
Ion Beam ◽  
Freeze Fracture ◽  
Ion Current ◽  
Ion Beam Etching ◽  
Pili Torti ◽  
Argon Ion ◽  
Scanning Electron

Ion beam etching and freeze fracture techniques were utilized in conjunction with scanning electron microscopy to study the ultrastructure of normal and diseased human hair. Topographical differences in the cuticular scale of normal and diseased hair were demonstrated in previous scanning electron microscope studies. In the present study, ion beam etching and freeze fracture techniques were utilized to reveal subsurface ultrastructural features of the cuticle and cortex.Samples of normal and diseased hair including monilethrix, pili torti, pili annulati, and hidrotic ectodermal dysplasia were cut from areas near the base of the hair. In preparation for ion beam etching, untreated hairs were mounted on conducting tape on a conducting silicon substrate. The hairs were ion beam etched by an 18 ky argon ion beam (5μA ion current) from an ETEC ion beam etching device. The ion beam was oriented perpendicular to the substrate. The specimen remained stationary in the beam for exposures of 6 to 8 minutes.

Evaluation of Three Different Cleaners Recommended for Ultrafiltration Systems by Direct Observations of Commercial-Scale Spiral-Wound Ultrafiltration Membranes1

1988 ◽  
Vol 51 (2) ◽  
pp. 89-104 ◽  
Author(s):  
K. E. SMITH ◽  
R. L. BRADLEY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Visual Inspection ◽  
Membrane Materials ◽  
Direct Observations ◽  
Commercial Scale ◽  
Sweet Whey ◽  
Scanning Electron ◽  
Polysulfone Membranes ◽  
Spiral Wound

Efficacy of cleaners designed for use with ultrafiltration systems was determined by microbiological evaluation and through visual inspection using scanning electron microscopy. The ultrafiltration system containing two commercial-scale, polysulfone membranes was soiled with sweet whey (40°C) then rinsed with water and membranes were removed. One half of each membrane was soaked for 2 h at 38°C in one of the following solutions: control (no soaking), acid cleaner (pH 2.5), enzyme-based cleaner (pH 11.5) and chlorinated alkaline cleaner (pH 11.5). The membranes were repositioned in the ultrafiltration unit, rinsed with water, then removed and unwound for analysis. Sections of membrane, retentate spacer and permeate mesh were aseptically removed for enumeration of microorganisms remaining and for examination by scanning electron microscopy. Membranes cleaned with chlorinated alkaline cleaner averaged 2 × 103 CFU/50 cm2, enzyme-based cleaner 6 × 106/CFU, acid anionic cleaner 1 × 107 CFU and the control 5 × 107CFU. Scanning electron microscopy found soil and microorganisms present on all membrane materials exposed to all three cleaners.

Taxonomic Identification of Rhabdochona Species Found in Oncorhynchus Clarki Using Scanning Electron Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 1148-1149
Author(s):  
D. Young ◽  
R.A. Heckmann ◽  
J. S. Gardner
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digestive Tract ◽  
Cutthroat Trout ◽  
Parasitic Nematodes ◽  
Buffer System ◽  
Taxonomic Identification ◽  
Critical Point Drying ◽  
Cacodylate Buffer ◽  
Scanning Electron

Adult Rhabdochona nematodes, commonly parasitizing fish, were present in the digestive tracts of cutthroat trout in Little Cottonwood Creek, Utah. Cutthroat trout, Oncorhyncus clarki, are known to serve as both intermediate and definitive hosts for parasitic nematodes. The larval stage parasitizes almost any tissue of its host, but the adult is always found in the digestive tract. Due to the lack of key morphological features, scanning electron microscopy (SEM) was used to identify specific structures leading to the nematode's taxonomic identification.Cutthroat trout were obtained using a rod and reel and were dissected the same day. Nematodes were present in all 12 cutthroat trout residing in all parts of the digestive tract. The nematodes, Rhabdochona sp., were prepared for SEM using the following procedures. First, the parasites were fixed in 2% buffered glutaraldehyde, washed in sodium cacodylate buffer, and post fixed in a 1% solution of osmium tetroxide. The samples were then washed in the same buffer system and dehydrated through a graded alcohol series. Critical-point-drying removed the remaining fluids. Finally, the nematodes were placed on specimen stubs, sputter coated with gold, and each specimen examined with a JOEL-840 high resolution scanning electron microscope with micrographs taken at varying magnifications.

Freeze-fracture Scanning Electron Microscopy of Radial Keratotomy Incisions

1994 ◽  
Vol 117 (3) ◽  
pp. 399-401 ◽  
Author(s):  
Stephen A. Updegraff ◽  
Marguerite B. McDonald ◽  
Roger W. Beuerman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Fracture ◽  
Radial Keratotomy ◽  
Scanning Electron

scholarly journals Scanning Electron Microscopic Study of Modified Chloroplasts in Senescing Broccoli Florets

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Hirofumi Terai ◽  
Alley E. Watada ◽  
Charles A. Murphy ◽  
William P. Wergin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

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.

Sign in / Sign up

Export Citation Format

Share Document