Non-reducing Carbohydrates Research Articles

Growth and Metabolic Changes Occurring in Orchard Grass During Temperature Acclimation

Orchard grass (Dactylis glomerata L.) was examined as new top growth was produced at 22 C after acclimation to 22 C and 35 C and as new growth was produced at 35 C after acclimation to 22 C and 35 C Ribonucleic acid concentration of top growth decreased rapidly during a 5-week sampling period, and the rate and magnitude of decrease was greater in plants grown at 22 C than at 35 C. During the first 2 weeks, plants grown at 22 C contained higher concentrations of ribonucleic acid than those grown at 35 C, whereas the reverse was true during the latter 3 weeks The deoxyribonucleic acid concentration decreased during the sampling period, but the decrease was much less than with ribonucleic acid Shortly after top growth was removed, total water-soluble carbohydrate concentration of stubble was at a low level and varied irregularly. After 3 weeks, the concentration began to increase, and plants grown at 22 C accumulated more reserve carbohydrates than those grown at 35 C. Water-soluble nonreducing carbohydrates were at a higher concentration than reducing carbohydrates and followed the same trend as total water-soluble carbohydrates. Reducing carbohydrate concentration, however, was greater in plants grown at 35 C than in those grown at 22 C Leaves were examined microscopically and the results are discussed

Carbohydrases of the midgut of the leather beetle Dermestes maculatus

Larval and adult midgut extracts were investigated for carbohydrase activity, and the pH optima for the hydrolysis by the larval midgut of a number of non-reducing carbohydrates, were determined. The pH of the midgut contents of the adult and larva was measured and found to lie in the region of 6·7 to 7·0. The results show that a wide range of carbohydrases is present in the larvae, but the number is somewhat less in the adults. It appears that at least two enzymes are involved in the digestion of starch, one for the hydrolysis of the α1–4 bonds and the other for the α1–6 bonds, and that two invertases are present in the larva, α1–2 glucosidase and β2-1 fructosidase. In the adult the last is not present in significant amounts. Further, in both larvae and adults there is a specific α-galactosidase, which will not hydrolyse α1–6 galactosidic bonds, and also a specific trehalase. The β-galactosidic bonds of lactose are hydrolysed but β-glucosidase activity has not been detected. It is suggested that the difference between larval and adult digestive abilities results from independent larval and adult evolution.

Some non-reducing carbohydrates in animal tissues and fluids.

Some non-reducing carbohydrates in animal tissues and fluids.

Carbohydrate Metabolism in Higher Plant Tissues Infected With Obligate Parasites

Several reports (7, 8, 22) have described apparently fundamental changes in the rates and nature of respiratory pathways during infection of higher plant tissues by obligate parasites, particularly rust fungi. Although disease can cause increases of 400 % in rates with a marked lowering of C6/C1 ratios, there is considerable uncertainty about the carbohydrate changes which accompany the respiratory alteration. Allen (1) first reported increases in sucrose and hexoses in wheat infected by powdery mildew. Gerwitz and Durbin (10) have described increases in both reducing and non-reducing carbohydrates in wheat infected by rust fungi while otbers (5,15, 16) have reported marked decreases in both types of compounds. Shaw and Samborski (22) found increases at 3 and 7 days after infection of wheat with rust fungi, but at 5 and 10 days the diseased tissue contained less sucrose and hexose than healthy controls. Inman (13) has pointed out that the amount of infection and the stage of parasite development are two factors which are important in such studies. With heavy infection of the bean rust fungus, the levels of reducing and non-reducing carbohydrates increased by 50 and 300 %, respectively, just prior to sporulation. Subsequently, and within 72 hours, the levels fell to 50 % of control tissue. With progressively fewer infections per unit of leaf area the changes were neither as great nor as abrupt in time. In cases of light infection the concentrations of soluble carbohydrate did not fall below the levels in control plants. It is of interest that, despite the consistently low C6/C1 ratios in conjunction with high rates of respiration, only the usual hexoses and sucrose have been positively identified in detectable amounts in diseased tissue. Failure to observe changes in concentrations in carbohydrates, especially pentoses or heptuloses, postulated to arise by reactions of an oxidative pentose pathway, is not completely unexpected because of possible kinetic difficulties (i.e. small pool sizes). It is also possible that intermediates of glucose catabolism via shunt metabolism may be sequestered as phosphate derivatives and thus not readily identified by usual chromatographic analysis. Similar failure to detect changes in sugars have been reported for tissues in which low C6/C1 ratios have been induced by other means (2, 20). In instances of disease-induced changes in C6/C1 ratios, there is circumstantial evidence that an oxidative pentose pathway is involved. It has been shown that low C,/C1 ratios occurred in the infected areas of diseased tissues, not in adjacent uninvaded tissue. The germinating spores of the parasite show low C6/C1 ratios and all of the enzymes of the oxidative pentose pathway are present with the possible exccption of transaldolase (23). There are two reports of alterations in carbohydrates that appear to be related to respiratory changes due to infection by obligate parasites. Jain and Pelletier (14) reported increased labelling in sedoheptulose when plants with low levels of infection metabolized C1409 in the light. Wang (26) reported similar results and found that this change occurred in uninfected host cells of diseased leaves. In view of the association of respiratory changes with invaded tissue and the complicating role of light in these experiments, the increased synthesis of sedoheptulose by a pentose pathway in diseased tissue is not established. Furthermore, it is to be noted that in both papers the evidence presented for the occurrence of sedoheptulose apparently is based chiefly on the similarities of Rf values of a radioactive spot with known compounds, usually in one dimensional chromatograms. Other workers have not mentioned the presence of sedoheptulose in rusted tissue (10, 15, 22) and separation of sedoheptulose from fructose sometimes is difficult (3). A similar criticism can be advanced for Wang's admittedly tentative identification of inannose (26), also not indicated to be present in other studies, as a major component of diseased tissue. 'Received Jan. 30, 1962. 2 Published with the approval of the Director as Paper No. 1188, Journal Series, Nebraska Agricultural Experiment Station. Supported by funds from USPH, grant E-2000 and the Research Council, University of Nebraska. 3 Present address, Shade Tree Laboratory, University of Massachusetts. Field Station. Waltham. Mass.

Studies on the Chemical Constituents of some local Weeds in the Aspect of Agriculture. Part I. Humification of Arousa (Justicia Adhotoda) Leaves under Constant Moisture Level and Variations in the Amounts of Carbohydrates

The reducing and the nonreducing carbohydrate constituents of Arousa (Justicia Adhotoda) leaves were extracted with the solvents (70–80% of alcohol, cold water, hot water, 1% cold HCl, 5% hot NaOH, 5% hot HCl, 72% cold H2SO4) as recommended by Rosenthaler (1930). The percentages of the reducing and the nonreducing carbohydrates were estimated in each extract. The carbohydrate constituents in the leaves, when humified alone, and, when they were mixed with the soil at 15% moisture level, were estimated. It was evidenced from these experiments that the decomposition of all reducing and nonreducing carbohydrates including the pectins, hemicelluloses, celluloses and lignins was much greater when the leaves were mixed with the soil than when they were humified alone under the same moisture level. This emphasizes the role of micro-organisms which develop in the soil during humification. The order of the decomposition of these carbohydrates during humification of the leaves, either alone or when mixed with the soil, was reducing sugar > non reducing carbohydrates > pectin > hemicelluloses > celluloses > lignin. From the data of the organic carbon, total nitrogen, mineral nitrogen, organic nitrogen as well as C : N ratio of the samples it was observed that the ratio of C : N decreased in all cases but the decrease is maximum when leaves were mixed with the soil and allowed to humify. From the increase in the ammoniacal and nitrate nitrogen by humifying the leaves in the soil, it has been suggested that Arousa, though a nonleguminous plant, may prove to be a potential green manure.

Über die löslichen Kohlenhydrate der GrünalgeAcetabularia mediterranea und deren quantitative Veränderungen in kernhaltigen und kernlosen Teilen

1. The uninucleate green algaAcetabularia mediterranea contains the following soluble carbohydrates: fructose, sucrose very small amounts of glucose and other sugars chiefly consisting of fructose polymers on paper chromatograms the latter behave like fructosans of higher plants. 2. In enucleated entire cells and cell parts the contents of reducing and non-reducing carbohydrates rise much more than in comparable nucleated cells. 3. This increase in content of soluble carbohydrates is probably due to the fact that in enucleated parts synthetic processes consuming carbohydrates (for example the synthesis of cell wall material and proteins) are weakened and later stopped. Therefore more substrate is available for the synthesis of fructose and fructosans. 4. The stop of cell growth, of protein synthesis and of all other synthetic processes studied to date in enucleated parts cannot be explained by the absence of products of photosynthesis, but must have other reasons. 5. Enucleated cell parts of the apical region are more active in carbohydrate metabolism than equally long parts of the basal region.

Degradation of Sugars on Ion-Exchange Columns of ‘Amberlite IRA 400 (OH′)’

IT has recently been suggested by Roseman et al.1 that columns of ‘Amberlite IRA 400 (OH′)’ might be used for the separation of certain reducing and non-reducing carbohydrates. Our own experience with this resin suggests that very carefully controlled conditions would be necessary if reliable quantitative results are to be obtained. During an investigation of the non-volatile organic acid components of apple juice and cider, it has been found that sugars are extensively degraded by ‘Amberlite IRA 400’ used in the OH′ form, organic acids being the main products of degradation.

General Method for Paper Chromatographic Analysis of Reducing and Nonreducing Carbohydrates and Derivatives

PREVIOUS ARTICLEThe National Academy of Sciences: Abstracts of Papers Presented at the 1949 Autumn Meeting, Rochester, New York

Biochemical Studies on ^|^ldquo;Miso^|^rdquo;, Fermented Soy-bean Paste. Part II

In order to ascertain the influence of temperature upon the ripening of “miso” five series of samples were kept for fermentation at 55°, 35°, 27-32°, 25° and 15-25° respectively. The samples taken at different intervals were analysed and at the same time the chemical changes during the steeping and boiling of the soy-beans were determined.It has been confirmed that the fermentation at 55° proceeds most rapidly attaining the maximum after 8-12 days, at a lower temperature the fermentation proceeds more slowly, thus wanting 15-25, 20-30 and 40-60 days or ripening at 35°, 25° and 15-25° respectively. The amount of ammoniacal nitrogen and free acid was comparatively large at 35°.It has also been observed that the ripening of “miso” is much accelerated by the enzyme action of “koji”. By the steeping of the soy-beans the increase of reducing sugars and free acids is noticeable and by boiling them some proteins, reducing and non-reducing carbohydrates are dissolved in water.The author wishes to express his cordial thanks to Professors U. Suzukiand R. Sasaki for their kind advice. The expence of this research waskindlydefrayed by the Association of the Tokyo Miso Manufacturers.

Ammonium Metavanadate as a Reagent for Reducing Carbohydrates.

A reagent consisting of 2% ammonium metavanadate in 10% sodium carbonate solution has proved effective in the detection of reducing carbohydrates or of non-reducing carbohydrates after hydrolysis. To make a test we heat on the water-bath 2 cc. of a 0.25% or 0.50% solution of the compound under consideration with 5 cc. of the reagent. A brownish to yellow color develops with a slight precipitate. On the addition of 1% hydrochloric acid, the mixture becomes clear and assumes a characteristic green color, due to the reduction of the metavanadate to a compound in which vanadium holds a lower valence. The acid must be added in quantities just sufficient to neutralize the reaction mixture, the point of neutralization being determined with litmus paper. The following compounds reduced with the formation of the characteristic color: pentoses (xylose, arabinose, rhamnose); hexoses (glucose, glucosamine, levulose, galactose, mannose); disaccharides (lactose, maltose, cellobiose). The following compounds reduced only after preliminary subjection to hydrolysis followed by neutralization: disaccharides (sucrose, trehalose); trisaccharides (raffinose, melizitose); polysaccharides (dextrin, starch, inulin, glycogen, cellulose); glucosides (aesculin, amygdalin, arbutin, phloridzin, strophantin, picrotoxin, salicin, saponin); gums (arabic, acacia, tragacanth); glycoproteins (mucin, ovomucoid); glycolipins (phrenosin); nucleic acid. Compounds other than carbohydrates also reduced. Cysteine gave a green color; lactic acid, a royal blue; oxalic acid, a green; mucic acid and citric acid, dark blue; tartaric acid, a royal blue with a purplish tinge; and pyruvic acid, green. The reagent, however, is more sensitive to the sugars than to the organic acids. The limit of sensitivity for glucose is 0.03%. Citric acid reduces in a 3% solution, but not in a 2% solution. Tartaric acid reduces in a 2% solution, but not in a 1% solution. Lactic acid does not react in a 0.9% solution.