The gills of the coelacanth, Latimeria chalumnae , a study in relation to body size

1995 ◽  
Vol 347 (1322) ◽  
pp. 427-438 ◽  
Keyword(s):  
Electron Microscopy ◽  
Weighted Average ◽  
Mass Range ◽  
Length Frequency ◽  
Latimeria Chalumnae ◽  
Transmission Electron ◽  
Life Habits ◽  
Low Mass ◽  
Gill Lamellae ◽  
Gnathiid Isopod

Measurements of the surface area of the gill lamellae of specimens of the coelacanth, Latimeria chalumnae have been made. This involved measurement of total filament length, frequency of lamellae along the filaments and the weighted average bilateral area of a single lamella. Regression analyses of these parameters which combine to give total area were made for the mass range 434 g—80 kg. Results show that the slope is close to 0.81 which is similar to that of many other fishes. However, the intercept value is exceptionally low and confirms the low mass-specific measurements made on two 10 kg specimens in 1972. Material from a recently caught specimen has been used to extend previous transmission electron microscopy by the use of scanning electron microscopy. The surface of epithelial cells on lamellae and filaments is covered in microvilli and microridges with transitional zones. The appearance of microridges suggests that they may have arisen by coalescence of microvilli. Ventilatory movements of the mouth and operculum (three to four per minute) have been observed using videorecordings of resting specimens in caves. Specimens of the larval stage of a gnathiid isopod parasite were found but only on one of the nine sets of gills that were examined. It is concluded that this more extended study of gill morphometrics of Latimeria confirms predictions made from earlier comparative studies regarding the life habits of this fish which have also been confirmed by direct observation using submersibles.

Fast imaging method for native liposomes: cryo Electron Microscopy for use in research and quality monitoring

1989 ◽  
Vol 47 ◽  
pp. 744-745
Author(s):  
J. F. Roeding
Keyword(s):  
Electron Microscopy ◽  
Chemical Properties ◽  
Image Intensifier ◽  
Imaging Method ◽  
Electron Dose ◽  
Specimen Holder ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
Liposome Suspension ◽  
Low Mass

Because of their high affinity to biological membranes liposomes are used in cosmetics and pharmaceuticals. Encapsulated active agents can be transported through biological barriers into cells. Apart from chemical properties, the physical characteristics of liposomes determine their ability of penetration and resorption: Vesicle size, lamellarity (number of membranes) and homogeneity are criterias for the quality of liposome-formulations and usually can be measured with laser-light-scattering combined with e.g. NMR-spectroscopy. Classification of liposomes in type (lamellarity) and size or differentiation of liposomes from other particles e.g. oil-droplets or crystals however requires imaging of the liposomes in their native state. Cryofixation and subsequent cryo-electron-microscopy enable to recognize the form and the structure of liposomes. In view of the low mass of the liposome shell, contrast in a conventional transmission electron micoscope is too weak for rapid, reliable recording of these structures. Imaging in an energy filtered transmission electron microscope (EFEM), however, provides optimum contrast and hence a basis for the correct assessment of the liposome structure including measurement and classification.Using a special pair of tweezers, take a hydrophilic perforated film (Triafol) and mount it in the injector. Using a pipette, apply 5μl of liposome suspension on this film so that a clear drop is visible. The excess liquid is removed by placing a piece of paper on the film for about 2 seconds. After this, the injector is immediately shot into the cryogen (ethane liquid). Removed from the cryogen and loaded in the specimen holder the specimen can be tranferred to the cryo EM and observed at minimum electron dose on the TV monitor using the image intensifier camera.

A technique for the study of histozoic myxosporean cysts: SEM of faces of partially cut wax embedded blocks

1990 ◽  
Vol 48 (3) ◽  
pp. 780-781
Author(s):  
Paul Odense ◽  
David Cone
Keyword(s):  
Electron Microscopy ◽  
Simple Technique ◽  
Host Tissue ◽  
Histological Techniques ◽  
Live Fish ◽  
Transmission Electron ◽  
Embedded Blocks ◽  
South Shore ◽  
Gill Lamellae ◽  
The City

Myxosporeans include many histozoic protist parasites of fishes in freshwater and marine environments worldwide and in a number of systems constitute important pathogens. Most species produce trophozoites that form obvious and often grotesque, cyst-like structure s within the host tissue. Traditionally, these trophozoites have been studied by means of either light or transmission electron microscopy. We have developed a simple technique whereby SEM can be used to supplement traditional light microscopical observations.Specimens of Myxobolus lamellus Grinham and Cone, 1990 were chosen because of the unusual nature of the trophozoite cyst, which is compartmentalized instead of the hollow fluid-filled sac typical of most species. The material was collected from the secondary gill lamellae of Catastomus commersoni living in a small lake in south shore Nova Scotia, 45 km west of the city of Halifax. Live fish were transported to the laboratory and necropsied. Cysts were fixed in 10% neutral buffered formalin for several days before being dehydrated and embedded in Paraplast using routine histological techniques.

Effects of lampricides on the gill ultrastructure of larval sea lampreys and rainbow trout fry

1994 ◽  
Vol 72 (9) ◽  
pp. 1653-1664 ◽  
Author(s):  
Jon Mallatt ◽  
R. Dale McCall ◽  
J. Franklin Bailey ◽  
James Seelye
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rainbow Trout ◽  
Petromyzon Marinus ◽  
Ion Uptake ◽  
Intercellular Spaces ◽  
High Susceptibility ◽  
Transmission Electron ◽  
Sea Lampreys ◽  
Gill Lamellae

Larval lampreys (Petromyzon marinus) and rainbow trout fry (Oncorhynchus mykiss) were exposed to toxic solutions of the lampricidal chemicals TFM (3-trifluormethyl-4-nitrophenol) and Bayer 73 (5,2′-dichloro-4′-nitrosalicylanilide). Both species were exposed to their 9-h LC100 for 9 h or until they were near death. The respiratory lamellae of the gills were then studied with transmission electron microscopy. In lampreys, damage was confined to presumed ion-uptake cells. Both lampricides produced similar changes in these cells: cell rounding, enlargement of mitochondrial profiles, vacuolization of the cytoplasm, and widening of the intercellular spaces. Bayer 73 caused a greater incidence of necrosis of ion-uptake cells than did TFM. Exposure to lethal TFM/Bayer-73 mixtures (containing 0.4–1.6% Bayer 73) affected lamprey gill lamellae in the same way as did Bayer 73. Unlike lamprey gills, trout gills were entirely unaltered by levels of the lampricides lethal to trout. These findings suggest that (i) disruption of ion-regulating cells contributes to the mortality of lampreys exposed to lampricides and to the high susceptibility of lampreys to TFM; (ii) the mechanisms of cytotoxicity of TFM and Bayer 73 are similar.

Light and electron microscopic studies on Myxobolus egyptica sp. nov. (Myxozoa, Myxosporea), infecting the hornlip mullet Oedalechilus labiosus from the Red Sea

2011 ◽  
Vol 56 (3) ◽  
Author(s):  
Abdel-Azeem Abdel-Baki
Keyword(s):  
Electron Microscopy ◽  
Red Sea ◽  
Direct Contact ◽  
Developmental Stages ◽  
Mature Spore ◽  
Host Cells ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Microscopic Studies ◽  
Gill Lamellae

AbstractA new myxosporean, Myxobolus egyptica sp. nov., was described from the gills of the hornlip mullet Oedalechilus labiosus, collected from the Red Sea at Al-Quseir city, Egypt. The prevalence of infection was 12/72 (16.66%). Myxobolus egyptica was identified on the basis of spore morphometry, histology and transmission electron microscopy. It was distinguished from all previously reported Myxobolus spp. by its shape, dimensions of the mature spore 10.0 ± 0.6 (9.5–10.5) μm in length, 8.5 ± 0.4 (8.0–9.0) μm in width and 8.7 ± 0.5 (8.4–9.2) μm in thickness, polar capsules, locality and host. The parasite formed intrafilamental cyst-like plasmodia. These plasmodia caused curling and atrophy of the gill lamellae. The ultrastructural analysis revealed a double-unit plasmodial membrane which was in direct contact with the host cells and had numerous vesicles. Some mitochondria were found below this membrane. The disporic pansporoblast was earliest recognizable stage of sporogenesis. Advanced developmental stages of spores and mature spores were reported.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

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.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

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).

Transmission Electron Microscopy Studies of Pore Cells in Limax Maximus

1977 ◽  
Vol 35 ◽  
pp. 656-657
Author(s):  
B. S. Beltz
Keyword(s):  
Electron Microscopy ◽  
Cell Periphery ◽  
Salivary Duct ◽  
Terrestrial Mollusc ◽  
Buccal Ganglia ◽  
Transmission Electron ◽  
Pore Cells ◽  
Gland Tissue ◽  
Storage Area ◽  
Limax Maximus

The cells which are described in this study surround the salivary nerve of the terrestrial mollusc, Limax maximus. The salivary system of Limax consists of bilateral glands, ducts, and nerves. The salivary nerves originate at the buccal ganglia, which are situated on the posterior face of the buccal mass, and run along the salivary duct to the gland. The salivary nerve branches several times near the gland, and eventually sends processes into the gland.The pore cells begin to appear at the first large branch point of the salivary nerve, near the gland (Figure 1). They follow the nerve distally and eventually accompany the nerve branches into the gland tissue. The cells are 20-50 microns in diameter and contain very small nuclei (1-5 microns) (Figure 2).The cytoplasm of the pore cells is segregated into a storage area of glycogen and an organelle region located in a band around the cell periphery (Figure 3).

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