Acidified 2,2-dimethoxypropane was used to chemically dehydrate biologic tissues for examination in the electron microscope. The ultrastructural integrities of single-celled algae, plant tissues (cotyledon, root, leaf) and animal tissues (liver, pancreas, muscle, cartilage) were maintained. Our technique was simpler and quicker than physically exchanging water for organic solvents (e.g., acetone, ethanol) as generally performed in microscopy.

Thermodynamic acidity constants and limiting ionic mobilities were determined for polyprotic non‐chromophore analytes using capillary electrophoresis with capacitively coupled contactless conductivity detection. It was not necessary to work with buffers of identical ionic strength as ionic strength effects on effective electrophoretic mobilities were corrected by modeling during data evaluation (software AnglerFish). The mobility data from capillary electrophoresis coupled to conductivity detection were determined in the pH range from 1.25 to 12.02 with a high resolution (36 pH steps). With this strategy, thermodynamic acidity constants and limiting ionic mobilities for various acidic herbicides were determined, sometimes for the first time. The model analytes included glyphosate, its metabolites, and its acetylated derivates (aminomethyl phosphonic acid, glyoxylic acid, sarcosine, glycine, N‐acetyl glyphosate, N‐acetyl aminomethyl phosphonic acid, hydroxymethyl phosphonic acid). The obtained data were used in simulations to optimize separations by capillary electrophoresis. Simulations correlated very well to experimental results. With the new method, the separation of glyphosate from interfering components like phosphate in beer samples was possible.

Lipid and protein, which comprise the compositional bulk of the intracellular cytoplasm of dicotyledonous oilseeds, are located principally in spherosomes (oleosomes) and protein bodies (aleurone grains), respectively (6, 10). Starch, seldom present in dicotyledonous oilseeds, including cottonseed, is sequestered in starch grains. The intracellular sites ofother noncellulosic carbohydrates, particularly free sugars, however, are unknown.In this communication, we describe both the amounts and the intracellular distributions of free sugars in cottonseed. Cottonseed contains by weight about 10% of these sugars, the composition of which has been examined previously (2,7,9). MATERIALS AND METHODS Tissue. Cottonseed (Gossypium hirsutum L.), var Acala 4-22-77 'Glandless,' was dehulled with a Bauer mill and stored at 4°C over Drierite. Subcellular Fractionation. A modification of the method of Yatsu and Jacks (10) was used in which refined cottonseed oil replaced glycerol as the isolation medium, and the centrifugation steps were 1,IOOg for 2.5 min and 3,000g for 15 min. For analyses, isolation medium and native lipids were removed from each fraction by repeated suspension in hexane followed by centrifugation, and the samples were dried in vacuo.Extraction of Free Sugars. Fifty-mg samples were extracted three times with 50 ml of 76% (v/v) aqueous ethanol and the extracts were combined. Further extractions rendered no additional sugars. Ethanol was evaporated in vacuo and either aqueous or 76% ethanolic solutions of the original ethanol-soluble material were analyzed for free sugars.Sugar Analyses. Total sugars in aqueous extracts were assayed by the anthrone reaction (5), and reducing substances by the TPTZ2 reaction (1). ' To whom inquiries and reprint requests should be sent.2Abbreviation: TPTZ, ferrous-2,4,6-tripyridyl-S-triazine.TLC was performed according to Conkerton et al. (3). Precoated Sil G-25 plates (Brinkmann Instruments, Inc.) were used with chloroform:methanol (60:40, v/v). Detection occurred by spraying with naphthoresorcinol-sulfuric acid (8) and, for reducing substances, spraying with TPTZ reagents and substituting oven heating for the boiling water bath. Ninhydrin spray was used for amines (8).HPLC was performed with Waters Associates chromatograph model ALC/GPC 244 with a ,uBondapak-carbohydrate column and a R401 differential refractometer (detector). The solvent was 83% acetonitrile:17% water with a flow rate of 1.5 ml/min, and methyl a-D-glucoside was an internal standard.Except for tetrasaccharides I and II, sugars were identified from comparisons to authentic samples subjected to TLC and HPLC. Identifications of the tetrasaccharides were deduced from other chromatographic properties (7). RESULTS AND DISCUSSIONThree lipid-free preparations were obtained: the original cellfree homogenate (first supernatant) and two fractions: nonparticulate cytoplasm (subsequent supernatants) and protein bodies

SynopsisThe crystal lattice of native cellulose from four sources has been investigated by electron diffraction techniques. The four sources were: cotton, ramie, a bacterial cellulose (Acetobacter xylinum), and an algal cellulose (Vuloniu ventricosu). Evidence for the existence of a t least two different unit cells is provided. There were no systematic absences of odd-order OkO reflections in any of the cellulose patterns, therefore, it was concluded that neit,her cellulose cell falls into the P21 space group.