Biomaterial Database

Use of freeze-substitution and molecular distillation drying in the preparation of Dunaliella parva for ion localization studies by X-ray microanalysis. 1993

M A Hajibagheri, and T J Flowers

Electron Microscopy Unit, Imperial Cancer Research Fund, London, United Kingdom.

The determination of ion concentrations within cells and sub-cellular compartments remains a difficult procedure, as the volumes to be analyzed are rather small. X-ray microanalysis is sufficiently sensitive, and has adequate resolution, to measure these concentrations. The major difficulties are related to the preparation of material for analysis. We have compared the measurement of sodium, potassium, and chloride contents in a salt tolerant unicellular alga, Dunaliella parva, following either freeze-substitution (using two different resins) or molecular distillation drying. All three procedures gave similar results: after freeze substitution, ion contents were marginally (but not significantly) higher following embedding in Nanoplast MUV 116 resin than in Spurr resin. Since the Nanoplast can be polymerised at low temperatures, it has advantages over the Spurr resin.

UI	MeSH Term	Description	Entries
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion
D004577	Electron Probe Microanalysis	Identification and measurement of ELEMENTS and their location based on the fact that X-RAYS emitted by an element excited by an electron beam have a wavelength characteristic of that element and an intensity related to its concentration. It is performed with an electron microscope fitted with an x-ray spectrometer, in scanning or transmission mode.	Microscopy, Electron, X-Ray Microanalysis,Spectrometry, X-Ray Emission, Electron Microscopic,Spectrometry, X-Ray Emission, Electron Probe,X-Ray Emission Spectrometry, Electron Microscopic,X-Ray Emission Spectrometry, Electron Probe,X-Ray Microanalysis, Electron Microscopic,X-Ray Microanalysis, Electron Probe,Microanalysis, Electron Probe,Spectrometry, X Ray Emission, Electron Microscopic,Spectrometry, X Ray Emission, Electron Probe,X Ray Emission Spectrometry, Electron Microscopic,X Ray Emission Spectrometry, Electron Probe,X-Ray Microanalysis,Electron Probe Microanalyses,Microanalyses, Electron Probe,Microanalysis, X-Ray,Probe Microanalyses, Electron,Probe Microanalysis, Electron,X Ray Microanalysis,X Ray Microanalysis, Electron Microscopic,X Ray Microanalysis, Electron Probe
D005612	Freeze Drying	Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.	Lyophilization,Drying, Freeze,Dryings, Freeze,Freeze Dryings,Lyophilizations
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
D017110	Freeze Substitution	A modification of the freeze-drying method in which the ice within the frozen tissue is replaced by alcohol or other solvent at a very low temperature.	Substitution, Freeze
D056890	Eukaryota	One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.	Eukaryotes,Eucarya,Eukarya,Eukaryotas,Eukaryote