Gas Chromatography Of Carbohydrates Research Articles

Activity of cell-wall degradation associated with differentiation of isolated mesophyll cells of Zinnia elegans into tracheary elements

Cell walls were prepared from cultured mesophyll cells of Zinnia elegans L. that were transdifferentiating into tracheary elements and incubated in a buffer to undergo autolysis. The rate of autolysis of cell walls was determined by measuring the amount of carbohydrate released from the cell walls into the buffer during incubation. During the course of culture of mesophyll cells, the autolysis rate increased markedly at the time when thickenings of secondary cell walls characteristic of tracheary elements became visible (after 48-72 h of culture), and thereafter the rate remained at a high level. Comparative studies on the autolysis rate of cell walls using various control cultures, in which tracheary element differentiation did not take place, revealed a close relationship between the autolysis rate around the 60th hour of culture and differentiation. Sugar analysis by colorimetric assays and gas chromatography of carbohydrates released from the cell walls detected uronic acid, arabinose, galactose, glucose, xylose, rhamnose, fucose, and mannose. Among these sugars, uronic acid was the most abundant, and accounted for approximately half of the total released sugars. The decrease of acidic polysaccharides in the primary cell walls during tracheary element differentiation was visualized by staining cultured cells with alcian blue at pH 2.5. These results suggest that active degradation of components of primary cell walls, including pectin, is integrated into the program of tracheary element differentiation.

The distribution of molecular species of monoglyco-sylceramides (cerebrosides) in different parts of bovine digestive tract

1. 1. Total monoglycosylceramide fractions were prepared from mucosa of bovine rennet stomach, duodenum, jejunum-ileum and colon ascendens. 2. 2. The lipids were characterized by thin-layer chromatography and mass spec trometry of intact molecules and by gas chromatography of carbohydrates after methanolysis. 3. 3. All regions contained galactosyi- and glucosylceramides. The amount of glucosylceramides was about 5 times higher in rennet stomach than colon ascendens. 4. 4. Trihydroxy base-containing species were present only in duodenum and jejunum-ileum. 5. 5. Galactosylceramide with sphingosine and 2-hydroxyhexadecanoic acid was exclusively present in colon ascendens. The corresponding glycosylceramide was not found.

Gas Chromatography of Carbohydrates in Alfalfa Nectar

Techniques used for the qualitative and quantitative analysis of caribohydrates in plant tissue are time consuming and tedious (5). Anaqysis of individual sugars such as glucose, fructose, and sucrose ha-s been. accomplished primarily by paper or -thin layer chromatography pWus elution and colori,metric or titrimetric techniques for final determination (2,9). Various conilbinations of techniques are ustuallly employed when making both quantitative and qualitative determinations but consideraible time and effort per sample is inevitable. This paper describes a technique whereby gas ahromatography.has been utiliied for rapid quantitative and qualitative determination of carbohydrates in alifalfa (Medicago sativa var. Sonora) nectar. The development of methods to analyze carbohydrates using gas-liq-uid chromatography has been hindered by the lack of v.olatility of polyhydroxy conpounds (11). However, since the discovery of procedures to prepare volatile carbohydrate derivatives much progress has been made in the preparation of these derivatives. Recent investigators have prepared several different volatile carbolhydrate derivatives (1,4,6). Sweeley et al. (7) were able to separate 20 different trimethylsi,lyl 'sugar de-rivatives 'by employing a SE-52 column and by tusing a temperature programming range from 1250 to 2500 at the tate of 2.30 increase per minute. WeVls (II)