Effect Of Maltose Research Articles

Assessment of various stresses and carbohydrates for their effect on the induction of embryogenesis in isolated wheat microspores

Isolated microspores of flowering plants can undergo embryogenesis when cultured in vitro under appropriate conditions. This process is triggered by various stresses including cold, heat and starvation. We have studied the effects of these stresses on the induction of embryogenesis in wheat microspores isolated from freshly cut or cold pretreated tillers. We show that the stress can be applied directly to microspore cultures, and efficient induction of embryogenesis can be obtained from microspores using a variety of stresses, namely cold (4°C), heat (33°C) and carbohydrate/nitrogen starvation. Cold pretreatment of tillers was able to replace stresses applied to microspores. For the first time we report on embryo formation in true ab initio wheat microspore cultures, not requiring any pretreatment of anthers or tillers prior to culture, in a maltose-containing medium. The effect of maltose on the induction of wheat microspore embryogenesis was specific and can possibly be attributed to its slow hydrolysis by plant cells, exerting starvation conditions early in culture and stable osmolarity of the medium later on. A comparison of three protocols for the induction of wheat microspore embryogenesis and plant regeneration has revealed no significant difference in plant yield, but the ploidy of the plants obtained was affected.

Effects of carbohydrate addition on the induction of somatic embryogenesis in Hevea brasiliensis

The effect of different carbohydrates was tested on early somatic embryogenesis of Hevea brasiliensis. Sucrose was replaced with maltose, fructose or glucose. Somatic embryo production was significantly higher with maltose. With maltose, the initial yellow colour of the calli turned orange, and dry matter production after 28 days' culture was half that obtained with sucrose. Maltose also reduced the soluble sugar content by around 60%, whereas in the presence of sucrose, the soluble sugar content of calli increased. On maltose medium, embryonic cells were initiated after 2 weeks, whereas calli obtained on media containing sucrose mostly consisted of parenchymatous cells. The embryogenic cells rapidly formed into globular embryos. The origin of the `maltose' effect is discussed: is it carbohydrate stress or a signal molecule? The effect of maltose was checked on 6 Hevea callus lines maintained in the laboratory.

Improvement of somatic embryogenesis in wild cherry (Prunus avium). Effect of maltose and ABA supplements

Three different types of morphogenesis were identified in embryogenic cultures of Prunus avium grown on a proliferation medium containing 0.54 μM NAA, 0.46 μM kinetin and 0.44 μM BA: a friable hyperhydric callus, repetitive embryogenesis and an embryogenic tissue. Translucent and white somatic embryos were produced from the three types of morphogenesis but mainly from the embryogenic tissue. These somatic embryos showed histological and cytological teratological features such as highly differentiated cells with shrunken cytoplasm and destructured nuclei. For the four lines studied, somatic embryo production was improved by transferring the embryogenic tissue to developmental media without auxin and cytokinin but supplemented with maltose alone or maltose and 10 μM ABA. Three weeks after transfer, the line showing the most embryogenesis produced 1404 somatic embryos per gram of embryogenic tissue. A concentration of 263 mM maltose significantly increased the number of white somatic embryos for L 10 line, while translucent somatic embryo production was improved by 88 mM maltose for L 16 line. The combination of maltose and ABA produced different effects with each line. When used with 88 mM maltose, 10 μM ABA significantly increased white somatic embryo production for two lines but decreased the production for one line. When combined with 263 mM maltose, ABA had no effect on white somatic embryo production but significantly decreased the number of translucent somatic embryos. Cells of white somatic embryos contained protein storage reserves and numerous lipid bodies, while those of translucent embryos did not contain storage reserves or lipid bodies. After a two-month cold treatment conversion rate of white and translucent somatic embryos reached 8.5% and 35.2% respectively.

Somatic embryo maturation and plant regeneration in Abies nordmanniana Lk

The effect of maltose and sucrose at 1, 3 or 6% (w/v) on maturation of somatic embryos of the conifer Abies nordmanniana was studied in five different cell lines. At all concentrations tested, maltose was superior to sucrose in terms of the number of mature somatic embryos formed as well as their germination percentage. Optinum maltose concentrations varied between 3.4 and 4.3% based on quadratic regression analysis. Mixtures of maltose and sucrose were not found to produce as good results as pure maltose. The addition of polyethylene glycol-4000 (PEG-4000) to medium with 3% maltose further increased the yield of somatic embryos. The promotive effect of PEG-4000 was mainly exerted during the formation precotyledonary embryos. Germinated plants were hardened, established in soil and they resumed growth the following spring.

Oral satiation and regulation of intake

The satiating effect of maltose and glucose was tested following oral application. Results showed significant suppression of subsequent cereal intake for both. Based on this finding, oral satiation is proposed to be the first and perhaps the most important in a sequence of mechanisms for regulating nutrient intake. Sensory recognition based on chemical structure rather than special attributes such as calorie content is proposed as the basis for this mechanism. Lactose and sucrose, two other sugars important in human nutrition, may also function in a similar manner.

The maltose regulon of Vibrio cholerae affects production and secretion of virulence factors.

The effects of maltose on production and secretion of virulence factors of Vibrio cholerae in strain X28214, classical biotype, and in maltose-defective transposon mutants constructed from this strain were characterized. Maltose was found to inhibit secretion of cholera toxin and to reduce production of the mannose-sensitive hemagglutinin and the soluble hemagglutinin-protease. In contrast, the amount of toxin-coregulated pilus was increased in the presence of maltose. The maltose effect was apparently mediated by genes of the maltose regulon, since inactivation of the malQ or malF gene of V. cholerae by transposon insertion was found to affect production and secretion of the same virulence factors that were responsive to maltose. The malQ and malF mutants showed, in addition, reduced virulence in an infant-mouse model. These results suggest that maltose may have a significant regulatory role in the production of virulence factors and that an intact maltose regulon is needed for full virulence of V. cholerae.

Effect of Maltose and Hormones on Callus Formation and Plant Regeneration in Isolated Microspore Culture of Japonica Rice (Oryza sativa L.)

Effect of Maltose and Hormones on Callus Formation and Plant Regeneration in Isolated Microspore Culture of Japonica Rice (Oryza sativa L.)

Effect of Maltose and Gelling Agent on Protoplast Culture Response in Indica Rice

Effect of Maltose and Gelling Agent on Protoplast Culture Response in Indica Rice

The influence of culture conditions on anther culture response of commercial varieties of Solanum tuberosum L.

The effect of media manipulatioss, temperature pretreatment, carbohydrate source, and seasonal variation on tetraploid potato anther cultures was investigated. The anther culture responses of three commercial Nordic potato varieties from Scandinavia and two from Germany were compared on different media manipulations. With most of the varieties, solid MS media gave better yields than other published media manipulations. Pretreatments at +6°C and at +30°C were studied on Pito and Danva varieties. The +6°C pretreatment and no pretreatment had the same effect on the anther culture response of cv. Pito, while with cv. Danva pretreatment at +6°C promoted embryogenesis. The +30°C pretreatment had no positive effect on anther culture response on either cultivar. The effect of maltose, melibiose and mannitol individually and in combination with sucrose were compared to normal sucrose medium in cv. Pito anther cultures. Anthers incubated on normal sucrose medium gave the highest embryoid and plant yields; the second highest plant yields were obtained on pure maltose medium. Strong seasonal variation was observed throughout the year in cv. Pito anther cultures. The percentage of anthers producing embryoids ranged from 15–20% during September and October to just 1–3% from February through May. The annual average embryoid production rate was 6.18%.

Retrogradation of Rice Starches Studied by Differential Scanning Calorimetry and Influence of Sugars, NaCl and Lipids

ABSTRACTIn waxy and nonwaxy rice starch gels the retrogradation process was a function of time. The enthalpy for rice starch gel with high amylose content was higher than those for low amylose content or for waxy starch samples. In all rice starch gels, samples stored under 25°C had lower enthalpy and higher endothermic onset temperature. In presence of sucrose, extent of retrogradation increased, while in presence of NaCl, it decreased. Effects of maltose, glucose and lipids were dependent on rice starch gel and storage temperature.

Effect of maltose on the response of potato anthers in culture

Anthers of the Solanum tuberosum genotype H3703 were cultured on medium containing equimolar concentrations of sucrose or maltose. It was found that significantly more pollen embryos became plants after culture on maltose and hence the yield of plants per 100 anthers cultured increased significantly. Mechanisms by which carbohydrate source may influence response to anther culture are discussed.

Effect of carbohydrate source on alfalfa somatic embryogenesis

Cultures of alfalfa ( Medicago sativa L. clone RA-3) were screened for their response to a wide variety of carbohydrate sources in the presence or absence of sucrose. Maltose, maltotriose, and soluble starch all act to improve the morphology and eventual conversion to plantlets of somatic embryos. Glucose, sucrose, and other carbohydrates do not have a similar effect. Additional studies were carried out with maltose since this carbohydrate also gives the highest embryo yield. The concentration optimum for maltose is about 4% (w/v). Maltose acts independently of sucrose and in a way which suggests that it serves as a nutritional, rather than as an osmotic, effector of embryogenesis. The effect of maltose on embryogenesis is dependent on the presence of NH 4 + whose optimum is approximately 15 mM. Embryogenesis on maltose will not occur in the absence of NH 4 +. A highly effective regeneration medium can be achieved by including NH 4 + and amino acids, especially proline, in a maltose-containing regeneration medium. Maltose is also useful in increasing embryo formation in genotypes which show low regeneration.

Effect of Maltose on Glucan Synthesis by Glucosyltransferases of Streptococcus mutans

The effects of added maltose on the activities of a preparation of crude glucosyltransferases (GTases) and purified dextransucrase (DS) were investigated to elucidate the inhibition mechanism of maltose on the synthesis of water-insoluble glucan (ISG) in Streptococcus mutans HS-6. Tri- and tetra-saccharides produced by crude GTases from sucrose in the presence of maltose were identified as panose (4-alpha-isomaltosylglucose) and 4-alpha-isomaltotriosylglucose which were responsible for the activity of DS involved in crude GTases. Kinetic studies on crude GTases in the presence of maltose showed similar results to those of DS except that the synthesis of ISG in the crude GTases was inhibited. Comparative studies of soluble products of crude GTases and DS in the presence of maltose were performed employing gel filtration on Sephadex G-15. The existence of oligosaccharides above hexasaccharide was revealed as the products of DS but not of crude GTases. These findings were interpreted in terms of the previously proposed mechanism of ISG synthesis by S. mutans, i.e., ISG should be synthesized from the preformed soluble glucan. It was indicated that oligosaccharides above hexasaccharide are utilized for ISG synthesis in the crude GTases system. From these results, the inhibitory mechanism of added maltose on ISG synthesis by crude GTases is considered as follows: DS synthesizes a series of 4-alpha-isomaltodextrinylglucose from sucrose and maltose, and the increase of added maltose results in the decrease of oligosaccharides responsible for synthesis of ISG.

The influence of the replacement of dietary sucrose by maltose on the formation and biochemistry of human dental plaque

Samples of 2-day plaque were collected before and during two 25-day diet periods from 24 subjects taking part in a double-blind cross-over study involving sucrose-and maltose-rich diets. The mean change in plaque pH measured after exposure to the respective sugar during the 3rd week of both diet periods was similar. The dry weight of plaque did not vary significantly as either diet progressed but the lowest mean value obtained was in the 4th week of the maltose diet. The extracellular polysaccharide content of plaque was lower in the maltose group than in the sucrose group ( p = 0.052). Plaque-invertase activity was not affected significantly by the diets but maltase activity was significantly higher in the 2nd and 4th weeks of the maltose diet ( p = 0.039; p = 0.012). The results suggest that the polysaccharide matrix of plaque formed in the presence of maltose as opposed to sucrose is different, which could be explained by the known effect of maltose in vitro on plaque glucosyl transferases

中枢電気活動と腸管運動に及ぼす活性Vitamin B<SUB>1</SUB>および糖質の影響

Effects of maltose, glucose and vitamin B1 on the central nervous system and intestinal movement were electrophysiologically examined by use of rabbits.1. On the arousal reaction and the evoked muscular discharge induced by stimulation of the brain stem reticular formation, and on the inhibitory effect of arousal reaction toward intestinal movement, activated vitamin B1,50%glucose and maltose mainly showed inhibitory effect. On the contrary, they showed facilitatory effect on the intestinal movement.2. On the evoked muscular discharge of fore and hind limbs induced by stimulation of the cerebral cortex, the small amount of 50%glucose and maltose showed inhibitory effect, on the contrary, the great amount of 50%glucose and maltose showed facilitatory effect, and activated vitamin B1 showed both inhibitory and facilitatory effect in which no certain tendency was recognized.3. On the evoked muscular discharge induced by stimulation of the hippocampus,50% glucose and maltose showed facilitatory effect, on the other hand, activated vitamin B1 mainly showed inhibitory effect. Thus carbohydrate solution and activated vitamin B1 showed opposite effects.4. On the early components (N1, N2) of afferent average evoked potentials of the cerebral cortex induced by the sciatic nerve stimulation, activated vitamin B1,50% glucose and maltose showed facilitatory effect. On the contrary, they showed no significant effect on the late components (N4, N5).5. On the nociceptive reflex induced from the tibialis anterior muscle due to stimulation of the tibial nerve, activated vitamin B1,50%glucose and maltose showed facilitatory effect.6. On the H wave induced from M. gastrocnemius tibialis due to stimulation of the sciatic nerve, maltose,50%glucose and activated vitamin B1 showed facilitatory effect in which activated vitamin B1 and 50%glucose showed stronger effect than maltose. On the M wave the activated vitamin B1 and 50%glucose showed facilitatory effect, when compared with the effect on the H wave, effect on the H wave is considered stronger. Maltose showed no significant effect on the M wave.7. Activated vitamin B1,50%glucose and maltose increased more than 30% the threshold of arousal reaction and evoked muscular discharge due to stimulation of the reticular formation.5 %glucose slightly increased the threshold.From these completed results, it is revealed that activated vitamin B1 and carbohydrate (administrated at the same time) on one hand, showed facilitatory effect on the afferent pathway and the intestinal movement, but that on the other hand, they might show the inhibitory effect on the arousal reaction. The countermeasure has been discussed.

Effect of maltose on glucoamylase formation by Aspergillus niger.

Low levels of glucoamylase are produced when Aspergillus niger is grown on sorbitol, but substitution of the latter by glucose, maltose, or starch results in greater formation of glucoamylase as measured by enzymatic activity. Both glucoamylase I and glucoamylase II are formed in a yeast extract medium; however, glucoamylase I appears to be the only form produced when ammonium chloride is the nitrogen source. Maltose or isomaltose (1.4 x 10(-4)m), but no other disaccharides or monosaccharides, dextrins, dextrans, or starches, stimulated glucoamylase formation when added to mycelia pregrown on sorbitol-ammonium salts. The induction of glucoamylase by maltose was independent of sulfate concentration but showed a dependency on low pH and the absence of utilizable carbon sources.

Effect of Maltose on Polysaccharide Synthesis by a Cariogenic Streptococcus

Effect of Maltose on Polysaccharide Synthesis by a Cariogenic Streptococcus

Investigation of the active center of porcine-pancreatic amylase.

The effect of maltose was studied in porcine pancreatic amylase. At neutral pH 1% (29 mM) maltose produced with amylase a difference spectrum characteristic of the perturbation of tryptophan. The molar absorption difference at the maximum wavelength was Δ290= 1200. The difference spectrum appeared to be specific for maltose. Perturbation difference spectra measurements in 20% polyethylene glycol indicated that one tryptophyl side chain per mol amylase was involved in the interaction with maltose. The dissociation constant of the amylase · maltose complex calculated from the concentration dependence of the absorption difference at 290 nm was Ks= 13 mM. Maltose inhibited amylase activity competitively and an inhibition constant of Ki= 25 mM was obtained, a similar value to that found spectrophotometrically. It is assumed that the tryptophyl side chain interacting with maltose may be involved in the binding of substrate by pancreatic amylase.

Physiological Studies on the Mechanism of Tuberization of Potato Plants : Part 1. On the Tuber Formation of Potato Stem Segment Cultured under Sterile Condition

In the present investigation particular attention was given to a study of the influences of the concentrations and the sorts of sugars upon the tuber formation of potato stem segments cultured under sterile condition. Potato of the variety "Irish Cobbler" was used as material. When the potato stem segments were cultured in the syntheic medium containing low concentration of sucrose, such as 2% and 4%, the growth of lateral buds arising from the stem segments was recognized, but there resulted no tuber formation. On the other hand, by the cultures with high concentrations of sucrose as 6%, 8% and 10%, the tuber formation occurred at the tips of lateral buds of the stem segments and, at the same time the rate of tuber formation was accelerated in proportion to the increase of sucrose concentration in the medium. The effects of maltose, glucose, and fructose on the tuber formation were similar to that of sucrose. Judging from the results described above, it may be assumed that the tuber formation on the potato stem segments under the sterile culture is closely related to the amount of sugar added to the culture medium.