Showing papers on "Sucrose published in 1974"

Uptake and release of [14c]adenine derivatives at beds of mammalian cortical synaptosomes in a superfusion system

Abstract: (1) Synaptosomal fractions from guinea pig neocortical dispersions prepared in sucrose solutions were deposited from saline media as ‘beds’ on nylon bolting cloth. When incubated with 0.5–10 μm-[14C]adenine or adenosine in glucose bicarbonate salines, uptake of 14C from adenosine proceeded at about four times the rate of uptake of [14C]adenine. This contrasted with the relative uptake of the two compounds to neocortical tissue slices or to beds made from mitochondrial fractions, where uptake was similar with the two precursors. Uptake of both precursors to synaptosome beds was much greater than uptake of inosine. (2) Synaptosome beds, [14C]adenosine-loaded, contained 88 per cent of the 14C as 5′-adenine nucleotides, the remainder being present as cyclic AMP, inosine, hypoxanthine and adenosine. When superfused, the 14C output consisted mainly of adenosine, inosine and hypoxanthine, with some 7 per cent of 5′-nucleotides and 4 per cent of cyclic AMP. (3) Electrical pulses and the addition of 50 mm-KCl each increased the efflux of 14C from superfused [14C]adenosine-loaded beds. The superfusates issuing after excitation contained the same 14C-labelled compounds as issued before, with a small increase in the proportional yield of adenosine. The additional output of 14C following electrical pulses was diminished by about 50 per cent by 0.5 μm-tetrodotoxin while that following KCl was not affected; it was however prevented when the superfusing fluids were free of Ca2+.

Change in Invertase Activity of Sweet Potato in Response to Wounding and Purification and Properties of Its Invertases

Abstract: When root tissue of sweet potato (Ipomoea batatas Lam.) was sliced, acid invertase activity, initially absent in freshly sliced tissue, appeared after a 3- to 6-hour lag phase, rapidly reached a maximum in 18 hours, and thereafter decreased. The increase in invertase activity was accompanied by a decrease in sucrose content of the root tissue. Alkaline invertase activity was present in fresh root tissue, but changed little after wounding. Acid invertase in wounded tissue and alkaline invertase in fresh tissue were purified and their properties were investigated. The acid invertase was a s-fructofuranosidase and was unaffected by substrate or by any of the cations and several metabolites. The alkaline invertase was more specific for sucrose, was inhibited by glucose and glucose 6-phosphate, and displayed non-Michaelis-Menten kinetics.

Role of Free Space in Translocation in Sugar Beet

Abstract: The involvement of the free space in phloem loading of sucrose was studied in sugar beet source leaves (Beta vulgaris, L.). Sucrose, supplied exogenously to the abraded upper surface of leaves at a concentration of 20 mm, was available for translocation at rates similar to those obtained with photosynthesis. The exogenous sucrose substituted as a source of translocate for assimilate derived from photosynthesis when the latter process was disrupted by plasmolysis of the leaf with 0.8 M mannitol. The mesophyll symplast was not completely disrupted by this treatment, however. Data from the sugar uptake experiments indicate that phloem loading can occur from the free space.Isotope trapping of labeled sugars derived from (14)CO(2) was used to intercept and identify sugars passing through the free space prior to phloem loading. Increased translocation rates induced by 4 mm ATP or increased light intensity were accompanied by increased trapping of sucrose but not of glucose. The data support the view that sucrose passes into the free space prior to phloem loading.

Isolation of a Regulatory Mutant of Fructose-1, 6-diphosphatase in Saccharomyces carlsbergensis

Abstract: By selecting for growth on glycerol, but absence of growth on glucose, a mutant of Saccharomyces carlsbergensis was isolated which does not grow on glucose, fructose, mannose, or sucrose, which shows long-term adaptation to maltose, but which can grow normally on galactose, ethanol, or glycerol. In the mutant, fructose diphosphatase is not inactivated after the addition of glucose, fructose or mannose to the medium, resulting in the simultaneous presence of fructose diphosphatase and phosphofructokinase activity. Under these conditions, a cycle is probably catalyzed between fructose-6-phosphate and fructose-1,6-diphosphate, resulting in the net consumption of adenosine triphosphate and an immediate stop of protein synthesis.

Acceptance and sustenance value of naturally occurring sugars fed to newly emerged adult workers of honey bees (Apis mellifera L.)

Abstract: Thirteen sugars were fed in 0.125, 0.5, and 2 M solutions in water and in 0.5 M sucrose: L-arabinose, D-xylose, D-fructose, D-glucose, D-galactose, D-mannose, lactose, maltose, melibiose, sucrose, trehalose, melezitose, and raffinose. Survival, water consumption, and sugar consumption were measured. No sugar equaled sucrose in acceptance or sustenance. Reduced survival seemed to be associated with aldoses that contain axial hydroxyl groups at C2 or C4 in a C1 pyran ring (mannose, galactose, or arabinose) even if they were in a sucrose solution that ensures feeding. Acceptance was correlated with survival, but whether low acceptance is a consequence or a cause of mortality was not established. When 0.5 M sucrose was supplied separately, bees showed a strong preference for the sucrose solution and were not harmed by small quantities of the other sugars.

Nutritional studies of eastern spruce budworm (lepidoptera: tortricidae): i. soluble sugars

Abstract: An absolute requirement for sugar could not be shown but laboratory rearing experiments using artificial diets have demonstrated a definite increase in weight of adult spruce budworm (Choristoneura fumiferana (Clem.) Freeman) with increasing dietary levels of certain sugars. Males exhibit a threshold of 0.9% soluble sugars above which higher sugar levels produce no further increases in size. Females respond with an increase in size up to 4.0%, the highest level tested. Generally, faster development rates accompany greater mature weights on diets with higher nutrient levels.Maltose, raffinose, glucose, sorbitol, sucrose, and fructose are all good sugar sources. Galactose and trehalose are only slightly inferior. Lactose, ribose, melibiose, xylose, mannose, arabinose, and melezitose in the diet are little different from the sugarless control. Sorbose is somewhat inhibitory.Results of transfer experiments confirm the importance of sugar particularly during late larval development. They also indicate that a high protein diet during early instars has a significant effect on development rates. These results suggest that departure from the normal synchrony of development in the insect and its host can affect both rate of development and mature size of the insect.

Development of tuberous roots and sugar accumulation as related to invertase activity and mineral nutrition.

Abstract: Sucrose storage in tuberous roots was not observed when the tissues had very high activities of acid invertase. High activities of the enzyme were always present in the roots at early stages of their development. In species where the activity of the enzyme decreased during root development, sucrose was stored. Thus, acid invertase was undetectable in mature roots of carrots (Daucus carota L.) where sucrose formed almost 80% of the dry matter. Conversely, radish (Raphanus sativus L.) and turnip (Brassica rapa L.) roots, in which the activity of the enzyme remained high until maturity, did not store appreciable amounts of sucrose (2% and 9%, respectively, of the dry matter in the mature roots), reducing sugars being the main reserve (more than 80% of the dry matter in mature turnips). The correlation between sucrose content and acid invertase activity was furthermore evident in both sucrose- and hexose-storing roots when the activity of this enzyme was affected by changes in the mineral nutrition. Deficiencies of nitrogen and sulphur reduced the activity of acid and alkaline invertases and led to increase in sucrose content and decrease in reducing sugars. However, the decline of alkaline invertase activity in tissues low in acid invertase had no clear effect on sugar content. Sodium chloride (10(-1)M) affected acid invertase and sugars in a manner similar to that of the two deficiencies, but had practically no effect on alkaline invertase. The changes in sugar content produced by the variations in mineral nutrition were small in hexose-storing roots in relation to those of sucrose-storing roots. It is possible that this result is related to the different levels of acid invertase in the two types of roots.

Sucrose Lipids of Arthrobacteria, Corynebacteria and Nocardia Grown on Sucrose

Abstract: Arthrobacter paraffineus KY 4303, when grown on sucrose as the sole carbon source, produced novel glycolipids, either of which was different from trehalose lipid produced from n-alkane by the same microorganism Two kinds of glycolipids were isolated by chromatography on silicic acid columns Major components of these lipids were sucrose and α-branched β-hydroxy fatty acid One of the lipid (SL–1, having high polarity) was identified as 6-O-monofattyacyl glucosly-β-fructoside Another (SL–2, having low polarity) was partly characterized as sucrose ester of at least two moles of the fatty acidFormation of sucrose lipids was also demonstrated in sucrose-grown cells of several microorganisms of Corynebacteria, Nocardia and Brevibacteria, which were isolated as hydrocarbon-utilizing bacteria and could produce a considerable amount of trehalose lipid from n-alkane

Purification and some properties of an endocellular sucrase from a constitutive mutant of Bacillus subtilis Marburg 168.

Abstract: In Bacillus subtilis Marburg 168 an endocellular invertase-like sucrase can be induced by sucrose Sucrose, glucose and glycerol exert a catabolite repression on sucrase synthesis in both the inducible strain 168 and a constitutive derivative isolated in this laboratory Derepressed cultures of this constitutive mutant grown on glutamate and succinate procedure high levels of sucrase and are utilized as starting material for the purification process The purified preparation gives one single protein band after disc electrophoresis on polyacrylamide gel in the absence or in the presence of dodecylsulphate This enzyme has a molecular weight of about 55000 Sucrase is not a glycoprotein, it is activated by potassium ions and inhibited by p-hydroxymercuribenzoate Arguments are presented in favour of the hypothesis that, in vivo, 6G-phosphorylsucrose (6-O-phosphoryl-α-D-glucopyranosyl-1,2-β-d-fructof uranoside) rather sucrose serves as a substrate for this enzyme

Choloroquine inhibition of repair of DNA damage induced in mammalian cells by methyl methanesulfonate

Abstract: Chloroquine (ClQ) inhibited the repair of DNA damage produced in cultured rat liver cells by methyl methanesulfonate (MMS). MMS caused fragmentation of single-strand DNA in alkaline sucrose gradients. Repair of the damage was followed by observing the restoration of the normal sedimentation pattern at intervals after treatment. Repair was significant by 7 h and nearly complete at 24 h. Addition of ClQ during the repair peiod markedly reduced the rate of repair. Also, ClQ increased the lethality of MMS, which could be due to the inhibition of repair. ClQ was found to inhibit protein synthesis, but the effect on repair is probably not due entirely to this action since comparable inhibition of protein synthesis by cycloheximide produced a lesser degree of delay in repair.

Fructose-Lipids of Arthrobacter, Corynebacteria, Nocardia and Mycobacteria Grown on Fructose

Abstract: Arthrobacter paraffineus KY 4303, when grown on fructose as the sole carbon source, produced two novel glycolipids, both of which were different from trehalose-lipid produced from n-alkane and sucrose-lipids from sucrose by the same microorganism. Two kinds of glycolipids were isolated by repeating chromatography on silicic acid columns. One of the glycolipids (abbreviated as FL–1, having low polarity) was identified as fructose-6-corynomycolate and another (FL–2, having high polarity) was identified as fructose-1, 6-dicorynomycolate. Formation of fructose-lipids was also demonstrated in fructose grown cells of several strains of Corynebacteria, Nocardia, Mycobacteria and Brevibacteria.

Vein Loading: The Role of the Symplast in Intercellular Transport of Carbohydrate between the Mesophyll and Minor Veins of Tobacco Leaves

Abstract: Enzymatically separated leaf tissues of Nicotiana tabacum L., exhibiting good metabolic integrity, were used to evaluate the kinetics of sugar accumulation over the concentration range of 10 to 100 mm. Mesophyll cells exhibited Km values of 16 and 30 mm for glucose and sucrose, respectively; minor veins showed a reverse relationship, with Km values of 58 and 16 mm for glucose and sucrose, respectively. This would suggest that sucrose is preferentially absorbed by the minor vein net. Analysis of Vmax data indicates a reduction in the ability of isolated minor veins to accumulate substrate, implicating a symplastic rather than apoplastic route for intercellular transport. Competition studies demonstrate a common carrier for sucrose and glucose in both tissue types and suggest the presence of a “transport compartment,” entry to which is regulated by a critical intracellular sucrose concentration.

An Investigation of the Association Between the Hydrolysis of Sucrose and Its Absorption by Grains of Wheat

Abstract: The possibility of a linkage between the hydrolysis of sucrose and its uptake by wheat grain was investigated by culturing isolated grain in solutions of sugar. The grain hydrolyses sucrose to glucose and fructose, the catalyst seems to be extracellular acid invertase (s-fructofuranosidase), and the rate of hydrolysis is at least as fast as the deposition of starch. However, tris-HCl buffers inhibit hydrolysis but have no effect on the uptake of sucrose or on the speed of its conversion to starch. The grains absorb invert sugar (glucose and fructose) faster than sucrose, but more sucrose accumulates and less starch is produced from invert sugar than from sucrose. Culturing grain in a mixture of non-radioactive glucose or fructose and symmetrically labelled sucrose introduces very little asymmetry into the sucrose taken up, but sucrose accumulated from [fructosyl-14C]sucrose loses half the asymmetry, while sucrose produced from a mixture of [12C]glucose and [14C]fructose is not completely symmetrical. Both moieties of sucrose are converted into starch. It is concluded that absorption of sucrose is not dependent on extracellular hydrolysis, and intracellular hydrolysis of sucrose prior to conversion to starch is unlikely.

Sugar, organic acid, phenolic acid and plant growth regulator content of extracts of honeydew of the aphid Myzus persicae and of its host plant, Raphanus sativus

Abstract: SUMMARY The honeydew of Myzus persicae feeding on radish seedlings contains glucose, fructose, trehalose, melezitose and sucrose, of which glucose and fructose are present in radish seedlings. In addition, the honeydew contains eight organic acids, of which seven are present in uninfested seedlings and six are present in infested radish seedlings: of the eighteen phenolic acids in the honeydew, five are present in uninfested radish seedlings. Auxins, gibberellins, growth inhibitors and cytokinins are present in the honeydew. The presence of carbonate and bicarbonate previously recorded in honeydew of M. persicae could not be confirmed, but ammonia is present in fresh honeydew and accounts for its high pH.

Soluble carbohydrates in soybean

Abstract: Gas–liquid chromatographic analysis of the trimethylsilyl ethers of the ethanol (90%)-extracted carbohydrates (soluble carbohydrates) from soybean (Glycine max) plants demonstrated the presence of major quantities of O-methylinositol, glucose, fructose, and sucrose, minor quantities of myo-inositol, and two unidentified components. In leaf blades and petioles of 6-vveek-old plants, O-methylinositol accounted for more than 50% of the total soluble carbohydrates present.

Biology of mycorrhiza in ericaceae .3. movement of c-14 from host to fungus

Abstract: The major soluble carbohydrates of mycorrhizal and non-mycorrhizal roots of the cultivated cranberry, Vaccinium macrocarpon Ait., have been identified and quantitatively analysed. Mycorrhizal roots contained two sugars, mannitol and trehalose, not found in uninfected roots. As these sugars are abundant in extracts of endophyte mycelium grown in liquid culture, they appear to be of fungal origin. Analysis of neutral sugars derived by acid hydrolysis of insoluble residues showed an accumulation of a mannose-containing polymer in mycorrhizal roots. Mannose was a principal component of insoluble polymers in the endophyte. All soluble carbohydrates in the root, including mannitol and trehalose, became labelled after feeding '4CO2 to the shoots. Sucrose was the most strongly labelled sugar in both types of root. M\'lannose present in hydrolysates of mycorrhizal roots was more heavily labelled than that derived from uninfected roots but most 14C in insoluble fractions was found in glucose polymers. The hypothesis that the endophyte derives a supply of carbohydrate from its host plant is discussed.

Alkaline β-fructofuranosidases of tuberous roots: Possible physiological function.

Abstract: Alkaline invertase of roots of carrot (Daucus carota L.) did not hydrolyze raffinose while the acid invertase from the same tissue showed with this sugar ca. 60% of the activity found with sucrose. The activity of the two invertases was inhibited by fructose to a different extent, the K i value being ca. 4×10(-2) M and 3×10(-1)M, respectively, for the alkaline and the acid invertases from the roots of both carrot and turnip (Brassica rapa L.). It is proposed that fructose inhibition of acid invertase is of no physiological significance but that, in contrast, hexoses might regulate the activity of alkaline invertase.Comparing several species and cultivars, it was found that the content of reducing sugars and the activity of alkaline invertase of mature tuberous roots showed a positive correlation. This indicates that alkaline invertase may participate in the regulation of the hexose level of the cell, as was previously suggested for sugar-cane. A scheme is presented which proposes a way of participation of alkaline invertase in such a regulation, assuming that this enzyme is located in the cytoplasm and acid invertase is membrane-bound and mainly located at the cell surface.

Biochemical changes in the water-soluble carbohydrates during the development of chicory (Cichorium intybus Linn) roots

Abstract: Qualitative and quantitative changes in the water-soluble carbohydrates have been studied during the development of chicory roots. Besides sucrose, glucose and fructose, some inulin-type glucofructosans have been detected at all stages of development of the roots. The contents of the total water-soluble carbohydrates, free glucose and bound fructose increase whereas bound glucose decreases with the advancement in the growth of the roots. The ratio of the concentration of bound fructose to that of bound glucose increases with the ageing of the roots and reaches its maximum value around the month of June, indicating thereby that the maturity of the plant is characterised by an increase in the content of glucofructosans at the expense of sucrose.

Effects of fructose, sucrose and glucose feeding on plasma insulin concentrations and on adipose-tissue clearing-factor lipase activity in the rat.

Abstract: The rise in adipose-tissue clearing-factor lipase activity that results from feeding glucose to starved rats cannot be duplicated by giving equicaloric amounts of fructose or sucrose. An inability of the administered fructose and sucrose to raise the plasma insulin concentration probably accounts for this failure in enzyme response.

Influence of diet on sugars found by thin-layer chromatography in thoraces of honey bees, Apis mellifera L.

Abstract: Twelve sugars in 05 M solution in water and also in 05 M solution in 05 M sucrose were fed to newly emerged, caged honey bee workers After 11 to 27 hours, the sugars of ice water extracts of degutted thoraces were promptly analyzed by thin-layer chromatography Unlike published values for sugars in the hemolymph from healthy bees, trehalose was the predominant sugar in the thorax Lesser amounts of glucose and only traces of fructose were found Trisaccharides were found in the thorax after they were fed to bees Progress was made toward determining which nonsustentative sugars are toxic and which are not accepted Galactosides seem toxic per se and not to be progenitors of toxic galactose Galactosides and mannose gave no buildup of a particular sugar to indicate metabolic blockage Starved bees and moribund bees with empty crops contained glucose but no trehalose Analysis of thoracic sugars has potential value in diagnosis of bee poisoning

The role of sucrose and sucrose synthetase in carbohydrate plant metabolism.

Abstract: 1. The role of sucrose as a controlling factor of metabolic activities in the plant cell is discussed. 2. The problem of differentially modifying the rates of synthesis and cleavage of sucrose catalyzed by sucrose synthetase was studied using phenylglycosides, sugars, and divalent cations. 3. Trypsin action on sucrose synthetase resulted in an enzyme which retained the synthetic activity but lost about 80% of the cleavage activity. Saturation curves for sucrose which were hyperbolical for the native enzyme, were modified to sigmoidal for the trypsin treated enzyme.