X-ray microanalysis of freeze-dried ultrathin frozen sections of a regulating epithelium from the snail Otala

Appleton, T. C.; Newell, P. F.

doi:10.1038/266854a0

Cited by 26 publications

(7 citation statements)

References 6 publications

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“…Both the shell (Cameron, 1970) and the mantle (Machin, 1966) are effective barriers to water loss. In addition it has been found that the cytoplasm of mantle epithelial cells in dormant Otala lactea contained a large concentration of lamellate vesicles and associated microtubules (Newell & Machin, 1976; Appleton & Newell, 1977). This would reduce the vapour pressure deficit across the surface of the integument and thereby reduce evaporation.…”

Section: ( a ) Aestivationmentioning

confidence: 99%

“…This would reduce the vapour pressure deficit across the surface of the integument and thereby reduce evaporation. In addition it has been found that the cytoplasm of mantle epithelial cells in dormant Otala lactea contained a large concentration of lamellate vesicles and associated microtubules (Newell & Machin, 1976; Appleton & Newell, 1977). It has been suggested that these inclusions may be involved in the increase in ionic concentration in the apical cytoplasm (Appleton, Newell & Machin, 1979).…”

Section: ( a ) Aestivationmentioning

confidence: 99%

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Water‐regulatory Behaviour in Terrestrial Gastropods

Prior

1985

Biological Reviews

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Section: ( a ) Aestivationmentioning

confidence: 99%

Section: ( a ) Aestivationmentioning

confidence: 99%

Water‐regulatory Behaviour in Terrestrial Gastropods

Prior

1985

Biological Reviews

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“…Studies of transporting epithelia in molluscs are represented by a series of experiments done by Appleton & Newell (1977) and Appleton, Newell & Machin ( I 979) on the mantle epithelium of the desert pulmonate Otala lactaea. Exposure to drought causes the snail to aestivate, under which conditions the mantle epithelium becomes highly impermeable to water.…”

Section: (V) Molluscsmentioning

confidence: 99%

“…Appleton & Newell (1977) also analysed the distribution of silicon, phosphorus, sulphur, chlorine, potassium, calcium, iron and zinc in cytoplasm, nucleus and mitochondria. T h e mass per unit area of the dried sections, as deduced from the continuum count, decreased in a parallel fashion away from the apex.…”

Section: (V) Molluscsmentioning

confidence: 99%

“…All these gradients were absent or much less marked in active, non-aestivating snails, suggesting strongly that such a barrier is responsible for the water-retaining properties of the mantle. Appleton & Newell (1977) also analysed the distribution of silicon, phosphorus, sulphur, chlorine, potassium, calcium, iron and zinc in cytoplasm, nucleus and mitochondria. Regulating cells showed higher levels of iron and zinc, which were tentatively ascribed to the presence of enzyme co-factors.…”

Section: (V) Molluscsmentioning

confidence: 99%

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Electron‐probe X‐ray Microanalysis: Techniques and Recent Applications in Biology

Moreton¹

1981

Biological Reviews

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Summary (1) X‐ray microanalysis is a powerful technique, allowing the quantitative measurement of many elements of physiological interest, at physiological concentrations and with a spatial resolution typically of a few micrometres in bulk specimens, and a few hundred nanometres in thin sections. (2) The basic requirements are a focussed, high‐energy electron beam, X‐ray spectrometers and a means of visualizing the specimen. These facilities are found in a number of different types of commercial microanalysers, which may be based on either the transmission electron microscope, or the scanning electron microscope. Scanning microanalysers offer a lower image resolution, but are considerably more versatile than instruments based on the transmission electron microscope. (3) Preparing the specimen in a form that will withstand electron bombardment under high vacuum, and yet in which the elements to be analysed are retained in their original locations, is clearly the most critical step. For analysing diffusible elements, especially water‐soluble electrolytes, the only reliable method is to freeze as rapidly as possible, and analyse the tissue without any chemical treatment. (4) The best results are obtained if frozen sections are cut and analysed on a cold‐stage with their water content retained as ice. Procedures have been worked out for doing this, and for quantitative interpretation of the results, so that original tissue concentrations of the common electrolytes, phosphorus, sulphur and other elements of interest can now be measured with confidence. The original water‐content of different cell and tissue compartments can also be estimated from the mass‐loss on drying. (5) A simpler alternative is to freeze‐dry the frozen sections before analysis. The distribution of diffusible elements is probably not too much disturbed, spatial resolution is improved, and the visual image becomes much clearer, but quantitation is made more difficult and less reliable. Nevertheless this technique is frequently used. (6) For precipitated materials and for fluid samples, much simpler methods of preparation can be used. (7) The technique is the subject of a large and rapidly expanding literature, and is providing new information on the sub‐cellular distribution of electrolytes and other elements in many different tissues from animals and plants. (8) Some of the earliest applications to the study of diffusible ions were in the analysis of micropuncture samples from kidney tubules, where it has been possible to analyse many very small samples, and for several elements at once. Some preliminary information has also been obtained on the intracellular ion concentrations in kidneys subjected to different physiological conditions. (9) A particularly successful field has been the study of transporting epithelia, including vertebrate and insect digestive and excretory tissues, where the distribution of ions along the intercellular spaces has been shown not to agree with that predicted from the ‘standing gradient’ theory of osmotic coupling. Th...

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Localisation and quantification of elements in biological tissues by electron‐microprobe analysis

Dick

1979

Pestic. Sci.

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X-ray microanalysis of freeze-dried ultrathin frozen sections of a regulating epithelium from the snail Otala

Cited by 26 publications

References 6 publications

Water‐regulatory Behaviour in Terrestrial Gastropods

Water‐regulatory Behaviour in Terrestrial Gastropods

Electron‐probe X‐ray Microanalysis: Techniques and Recent Applications in Biology

Localisation and quantification of elements in biological tissues by electron‐microprobe analysis

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