Densitometric thin-layer chromatographic analyses of cholesterol inSchistosoma mansoni (Trematoda) adults and their excretory-secretory products

1983 ◽  
Vol 9 (11) ◽  
pp. 1483-1489 ◽  
Author(s):  
Bernard Fried ◽  
Frank J. Shenko ◽  
L. K. Eveland
Keyword(s):  
Thin Layer ◽  
Secretory Products

Intraspecific and interspecific pairing of Haematoloechus medioplexus (Trematoda) and Echinostoma revolutum (Trematoda) adults in vitro, and observations on H. medioplexus lipophilic excretory–secretory products

Parasitology ◽  
1982 ◽  
Vol 84 (2) ◽  
pp. 375-380 ◽  
Author(s):  
B. Fried ◽  
D. A. Leiby
Keyword(s):  
Fatty Acids ◽  
Thin Layer ◽  
Chromatographic Analysis ◽  
Petri Dish ◽  
Temperature Tolerance ◽  
Echinostoma Revolutum ◽  
Agar Substrate ◽  
Secretory Products ◽  
Thin Layer Chromatographic Analysis

SUMMARYIntraspecific pairing of Haematoloechus medioplexus and Echinostoma revolutum adults and interspecific pairing of H. medioplexus and E. revoltum adults were studied in vitro at 21 ± 1 °C and 30 ± 1 °C in Petri-dish cultures containing an agar substrate and a Locke's 1:1 solution overlay. Salinity and temperature tolerance tests showed that both species survived for 24 h in a Locke's 1:1 solution at 21 ± 1 °C and 30 ±1 °C. For behaviour studies, worms were placed 2 cm apart and then observed at various intervals from 5 min to 4 h. H. medioplexus and E. revolutum showed significant intraspecific pairing at 30±1 °C, whereas only H. medioplexus paired significantly at 21±1°C. Significant interspecific pairing of H. medioplexus and E. revolutum occurred at 21 ±1 °C and 30 ±1 °C. Thin-layer chromatographic analysis showed that H. medioplexus adults released mainly free sterol, along with traces of triacylglycerols and free fatty acids into a non-nutrient medium.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

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