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PubMed1978

Changes in starch content and amylase zymograms during storage of Golden Delicious and Cox's Orange Pippin apples.

Changes in starch content and amylase zymograms were followed during storage of Golden Delicious and Cox's Orange Pippin apples. Although the former was stored at 3-4 degrees C under controlled atmosphere (3--4% O2; 7--8% CO2 by volume) and the latter in air at 17 degrees C, in both, the multiple forms of amylases remained active, even after the starch content decreased to zero. It is the lack of starch substrate, therefore, rather than of enzymes that limits the amylase action in the stored apple.

Amylases↗
PubMed1982

[Long-term effects of various levels of dietary proteins as well as starch and sucrose as dietary carbohydrates on lipoprotein metabolism in the rat].

UNLABELLED: The repeatedly reported effect of proteins on lipoprotein metabolism leaves the question if this is caused mainly by the amount of amino acid composition of the protein itself, by the accompanying fat of cholesterol content, or by the contemporary predominant kind of carbohydrate in the diet. The conducted experiments with male rats, feeding them in 6 groups of 20 animals for one year semipurified, cholesterol-free diets with constantly 40 (J-)% fat in all diets, 13% (I), 20% (II, III, IV) or 40% (V, VI) protein and complementary carbohydrates (50% starch, 50% sucrose). III received sucrose only, IV starch only. VI was given additionally 0.8% arginine (arg). Rats on 40% protein exhibited higher total plasma cholesterol levels in comparison to 13% protein, HDL values were nearly identical in I, II, III, IV, and increased in V and VI. LDL was increased in V, compared to all other groups. CONCLUSION: The level of dietary protein alone may influence amount and distribution of lipoproteins in rats. LDL may be decreased by addition of arg, HDL remains unchanged. The type of carbohydrate had no influence on HDL or LDL on conditions of our experiment, whereas earlier experiments showed elevation of LDL values with sucrose in comparison to starch if cholesterol was present in the diet.

Animals↗
PubMed1992

Digestibility of proteins and starch (in vitro) of amphidiploids (black gram x mung bean) as affected by domestic processing and cooking.

The effects of different domestic processing and cooking methods on starch digestibility (in vitro) and protein digestibility (in vitro) of four strains of amphidiploids (black gram x mung bean) were investigated. An increase of 35 to 48% and 22 to 25% was observed in starch digestibility and protein digestibility, respectively, when the seed of amphidiploids were soaked for 18 h. Cooking (both of unsoaked and soaked seeds) and germination improved significantly the starch digestibility and protein digestibility of all the varieties.

Amylases↗
PubMed2000

A novel hydroxyethyl starch (Voluven) for effective perioperative plasma volume substitution in cardiac surgery.

PURPOSE: To compare the new hydroxyethyl starch HES 130/0.4 (Voluven) and the standard HES 200/0.5 (pentastarch) regarding effectiveness for plasma volume substitution and safety of large volumes in heart surgery. METHODS: Fifty-nine patients scheduled for coronary artery bypass grafting were enrolled in a prospective, randomised, double-blind, parallel-group, multicentre, clinical, phase III study. Hydroxyethyl starch was used as the exclusive artificial colloid for acute normovolemic hemodilution, priming of the heart lung machine, and for intra- and postoperative plasma volume substitution from induction of anesthesia until 16 hr after the end of surgery. Efficacy was evaluated by comparing the amount of colloid infused, hemodynamics, and colloid osmotic pressure (COP). Safety endpoints were blood loss, the use of allogeneic blood products, coagulation variables, and adverse events. RESULTS: Effectiveness, as assessed by the total amount of infused HES volumes within the treatment period, was similar between HES 130/0.4 and HES 200/0.5 (2,550 mL +/- 561 mL vs 2,466 mL +/- 516 mL). Also, no differences were found for the use of other colloids (pasteurised plasma), hemodynamics, and COP In HES 130/0.4 patients, the postoperative increase of von-Willebrand factor (vWF) was higher (P < 0.01), blood loss was lower, and less packed red blood cells were transfused. CONCLUSION: Hydroxyethyl starch 130/0.4 is an effective plasma volume expander in heart surgery and may be used as the sole artificial colloid to cover the perioperative period. We found a reduced influence of HES 130/0.4 on the physiologic postoperative increase of vWF.

Aged↗
PubMed1981

The effects of equal caloric amounts of xylitol, sucrose and starch on insulin requirements and blood glucose levels in insulin-dependent diabetics.

Xylitol has been suggested as a potentially useful sweetener in the diabetic diet. In 14 insulin-dependent diabetics a standard diabetic diet regimen was compared with diets in which starch was isocalorically exchanged in the breakfast meal by either 30 g xylitol or 30 g sucrose. Insulin requirement and blood glucose were measured using a glucose-controlled insulin infusion system. The results following breakfast with xylitol were similar to those after starch breakfasts. Sucrose, in contrast, induced a greater post-prandial rise in blood glucose levels despite counter-regulation by the glucose-controlled insulin infusion system. Insulin requirement after sucrose significantly exceeded (p less than 0.01) that after xylitol or starch during the first 60 min and 2 h respectively. No short-term side effects of xylitol were found.

Adult↗
PubMed2005

Mutations in wheat starch synthase II genes and PCR-based selection of a SGP-1 null line.

Wheat (Triticum aestivum L.) starch synthase II, which is also known as starch granule protein 1 (SGP-1), plays a major role in endosperm starch synthesis. The three SGP-1 proteins, SGP-A1, B1 and D1, are produced by three homoeologous SSII genes, wSSII-A, B, and D. Lines carrying null alleles for each SGP-1 protein have previously been identified. In this report, the mutations occurring in each wSSII gene were characterized, and PCR-based DNA markers capable of detecting the mutations were developed. In the null wSSII-A allele, a 289 bp deletion accompanied by 8 bp of filler DNA was present near the initiation codon. A 175 bp insertion occurred in exon 8 of the null wSSII-B allele. The insertion represented a recently discovered miniature inverted-repeat transposable element (MITE) named Hikkoshi that was first found in a wheat waxy gene. A 63 bp deletion was found at the region surrounding the junction of the fifth exon and intron of the null wSSII-D allele. Based on this information, we designed primer sets to enable us to conduct allele-specific amplifications for each locus. The applicability of these primer sets for breeding programs was demonstrated by reconstructing a line lacking all three SGP-1 proteins using marker-assisted selection. These markers will also be useful in breeding programs aimed at obtaining partial mutants missing one or two SGP-1 proteins.

Alleles↗
PubMed2002

High-level ethanol production from starch by a flocculent Saccharomyces cerevisiae strain displaying cell-surface glucoamylase.

A Strain of host yeast YF207, which is a tryptophan auxotroph and shows strong flocculation ability, was obtained from SaccharomYces diastaticus ATCC60712 and S. cerevisiae W303-1B by tetrad analysis. The plasmid pGA11, which is a multicopy plasmid for cell-surface expression of the Rhyzopus oryzae glucoamylase/alpha-agglutinin fusion protein, was then introduced into this flocculent yeast strain (YF207/pGA11). Yeast YF207/pGA11 grew rapidly under aerobic condition (dissolved oxygen 2.0 ppm), using soluble starch. The harvested cells were used for batch fermentation of soluble starch to ethanol under anaerobic condition and showed high ethanol production rates (0.71 g h(-1) l(-1)) without a time lag, because glucoamylase was immobilized on the yeast cell surface. During repeated utilization of cells for fermentation, YF207/pGA11 maintained high ethanol production rates over 300 h. Moreover, in fed-batch fermentation with YF207/pGA11 for approximately 120 h, the ethanol concentration reached up to 50 g l(-1). In conclusion, flocculent yeast cells displaying cell-surface glucoamylase are considered to be very effective for the direct fermentation of soluble starch to ethanol.

Aerobiosis↗
PubMed2002

A novel circulating loop bioreactor with cells immobilized in loofa ( Luffa cylindrica) sponge for the bioconversion of raw cassava starch to ethanol.

A circulating loop bioreactor (CLB) with cells immobilized in loofa sponge was constructed for simultaneous aerobic and anaerobic processes. The CLB consists of an aerated riser and a non-aerated downcomer column connected at the top and bottom by cylindrical pipes. Ethanol production from raw cassava starch was investigated in the CLB. Aspergillus awamori IAM 2389 and Saccharomyces cerevisiae IR2 immobilized on loofa sponge were placed, respectively, in the aerated riser column and non-aerated downcomer column. Both alpha-amylase and glucoamylase activities increased as the aeration rate was increased. Ethanol yield and productivity increased with an increase in the aeration rate up to 0.5 vvm, but decreased at higher aeration rates. The CLB was operated at an aeration rate of 0.5 vvm for more than 600 h, resulting in an average ethanol productivity and yield from raw cassava starch of 0.5 g-ethanol l(-1) x h(-1) and 0.45 g ethanol/g starch, respectively. In order to increase ethanol productivity, it was necessary to increase the dissolved oxygen (DO) concentration in the riser column and decrease the DO concentration in the downcomer column. However, increasing the aeration rate resulted in increases in the DO concentration in both the riser and the downcomer columns. At high aeration rate, there was no significant difference in the DO concentration in the riser and downcomer columns. The aeration rate was therefore uncoupled from the liquid circulation by attaching a time-controlled valve in the upper connecting pipe. By optimizing the time and frequency of valve opening, and operation at high aeration rate, it was possible to maintain a very high DO concentration in the riser column and a low DO concentration in the downcomer column. Under these conditions, ethanol productivity increased by more than 100%, to 1.17 g l(-1) x h(-1).

Aerobiosis↗
PubMed2006

Batch fermentations on synthetic mixed sugar and starch medium with amylolytic lactic acid bacteria.

The green crop drying industry in Denmark uses Italian rye grass, clover, and alfalfa as raw materials for the production of green pellets. The green crop drying industry solves its energy economical problems by heating and pressing of the green crop before drying. The produced sidestream is called brown juice. Brown juice was shown to be an excellent medium for lactic acid fermentation. The aim of this study was to investigate the utilisation of brown juice in the production of polylactic acid, where wheat starch would be added to increase the lactic acid yield and, thus, the feasibility of the process. A number of amylolytic lactic acid bacteria have been identified, and in this work, six different strains were tested for their ability to produce alpha-amylase and to utilise all sugars with high lactic acid yield in a medium with a complex composition of free sugars (brown juice) and starch. Lactobacillus plantarum A6 was the only strain that showed both a good lactic acid production and utilisation of starch in this medium. The growth rate of this strain was approximately 0.4 h(-1) and the lactic acid yield was 0.7.

Carbohydrate Metabolism↗
PubMed2006

The 53-kDa proteolytic product of precursor starch-hydrolyzing enzyme of Aspergillus niger has Taka-amylase-like activity.

The 53-kDa amylase secreted by Aspergillus niger due to proteolytic processing of the precursor starch-hydrolyzing enzyme was resistant to acarbose, a potent alpha-glucosidase inhibitor. The enzyme production was induced when A. niger was grown in starch medium containing the inhibitor. Antibodies against the precursor enzyme cross-reacted with the 54-kDa Taka-amylase protein of A. oryzae. It resembled Taka-amylase in most of its properties and also hydrolyzed starch to maltose of alpha-anomeric configuration. However, it did not degrade maltotriose formed during the reaction and was not inhibited by zinc ions.

Aspergillus niger↗
PubMed1998

Purification and properties of the raw-starch-digesting glucoamylases from Corticium rolfsii.

Corticium rolfsii AHU 9627, isolated from a tomato stem, is one of the strongest producers of raw-starch-digesting amylase. The amylase system secreted by C. rolfsii AHU 9627 consisted of five forms of glucoamylase (G1-G5) and a small amount of alpha-amylase. Among these amylases, G1, G2 and G3 were able to hydrolyze raw starch. Five forms of glucoamylase were separated from each other and purified to an electrophoretically homogeneous state. The molecular masses were: G1 78 kDa, G2 78 kDa, G3 79 kDa, G4 70 kDa, and G5 69 kDa. The isoelectric points were: G1 3.85, G2 3.90, G3 3.85, G4 4.0, and G5 4.1. These glucoamylases showed nearly identical characteristics except that G4 and G5 were unable to hydrolyze raw starch.

Amino Acid Sequence↗
PubMed2000

Cloning of the cyclodextrin glucanotransferase gene from alkalophilic Bacillus sp. A2-5a and analysis of the raw starch-binding domain.

The cyclodextrin glucanotransferase (CGTase) gene of alkalophilic Bacillus sp. A2-5a was cloned and expressed in Bacillus subtilis ANA-1 as a host. The DNA region included an open reading frame encoding a 704-amino-acid polypeptide with a typical raw starch-binding motif in its C-terminal region. The CGTase purified from Bacillus sp. A2-5a bound to raw starch as strongly as porcine pancreas alpha-amylase, as expected from the sequence motif. A chromosomal region (a DNA fragment of about 14.1 kbp) including the CGTase gene was also cloned and the nucleotide sequence was determined. Possible cyclodextrinase and putative cyclodextrin-binding protein genes were found in the flanking region of the CGTase gene, which implied that the novel starch-degradation pathway postulated for a gram-negative bacterium [Klebsiella oxytoca; Fiedler et al. (1996) J Mol Biol 256: 279-291] also exists in a gram-positive bacterium i.e. Bacillus.

Amino Acid Sequence↗
PubMed2004

Site-directed mutagenesis of the conserved threonine, tryptophan, and lysine residues in the starch-binding domain of Bacillus sp. strain TS-23 alpha-amylase.

The C-terminal domain of Bacillus sp. strain TS-23 alpha-amylase (BLA) has been known to be involved in the raw starch-binding activity of the enzyme. Sequence comparison revealed that Thr-527, Trp-545, Trp-561, Lys-576, and Trp-588 in this domain are highly conserved in the aligned enzymes. To understand structure-function relationships in the starch-binding domain of BLA, site-directed mutagenesis was conducted to replace these residues with leucine or isoleucine. The overexpressed enzymes have been purified by nickel-chelate chromatography, and the molecular mass of the purified proteins was approximately 64.5 kDa. Starch-binding assay showed that the binding activities of the single-mutated enzymes were significantly reduced, while the combinational mutations did not lead to a complete loss of the activity.

Amino Acid Sequence↗
PubMed1999

Dietary resistant starch and chronic inflammatory bowel diseases.

These studies were performed to test the benefit of resistant starch on ulcerative colitis via prebiotic and butyrate effects. Butyrate, propionate, and acetate are produced in the colon of mammals as a result of microbial fermentation of resistant starch and other dietary fibers. Butyrate plays an important role in the colonic mucosal growth and epithelial proliferation. A reduction in the colonic butyrate level induces chronic mucosal atrophy. Short-chain fatty acid enemas increase mucosal generation, crypt length, and DNA content of the colonocytes. They also ameliorate symptoms of ulcerative colitis in human patients and rats injected with trinitrobenzene sulfonic acid (TNBS). Butyrate, and also to a lesser degree propionate, are substrates for the aerobic energy metabolism, and trophic factors of the colonocytes. Adverse butyrate effects occur in normal and neoplastic colonic cells. In normal cells, butyrate induces proliferation at the crypt base, while inhibiting proliferation at the crypt surface. In neoplastic cells, butyrate inhibits DNA synthesis and arrests cell growth in the G1 phase of the cell cycle. The improvement of the TNBS-induced colonic inflammation occurred earlier in the resistant starch (RS)-fed rats than in the RS-free group. This benefit coincided with activation of colonic epithelial cell proliferation and the subsequent restoration of apoptosis. The noncollagenous basement membrane protein laminin was regenerated initially in the RS-fed group, demonstrating what could be a considered lower damage to the intestinal barrier function. The calculation of intestinal short-chain fatty acid absorption confirmed this conclusion. The uptake of short-chain fatty acids in the colon is strongly inhibited in the RS-free group, but only slightly reduced in the animals fed with RS. Additionally, RS enhanced the growth of intestinal bacteria assumed to promote health. Further studies involving patients suffering from ulcerative colitis are necessary to determine the importance of RS in the therapy of a number of intestinal diseases and the maintenance of health.

Animals↗
PubMed2003

The small subunit ADP-glucose pyrophosphorylase ( ApS) promoter mediates okadaic acid-sensitive uidA expression in starch-synthesizing tissues and cells in Arabidopsis.

Transgenic plants of Arabidopsis thaliana Heynh., transformed with a bacterial beta-glucuronidase (GUS) gene under the control of the promoter of the small subunit (ApS) of ADP-glucose pyrophosphorylase (AGPase), exhibited GUS staining in leaves (including stomata), stems, roots and flowers. Cross-sections of stems revealed GUS staining in protoxylem parenchyma, primary phloem and cortex. In young roots, the staining was found in the root tips, including the root cap, and in vascular tissue, while the older root-hypocotyl axis showed prominent staining in the secondary phloem and paratracheary parenchyma of secondary xylem. The GUS staining co-localized with ApS protein, as found by tissue printing using antibodies against ApS. Starch was found only in cell and tissue types exhibiting GUS staining and ApS labelling, but not in all of them. For example, starch was lacking in the xylem parenchyma and secondary phloem of the root-hypocotyl axis. Sucrose potently activated ApS gene expression in leaves of wild-type (wt) plants, and in transgenic seedlings grown on sucrose medium where GUS activity was quantified with 4-methylumbelliferyl-beta-glucuronide as substrate. Okadaic acid, an inhibitor of protein phosphatases 1 and 2A, completely blocked expression of ApS in mature leaves of wt plants and prevented GUS staining in root tips and flowers of the transgenic plants, suggesting a similar signal transduction mechanism for ApS expression in various tissues. The data support the key role of AGPase in starch synthesis, but they also underlie the ubiquitous importance of the ApS gene for AGPase function in all organs/tissues of Arabidopsis.

Arabidopsis↗
PubMed2003

Cloning and characterization of the granule-bound starch synthase II gene in rice: gene expression is regulated by the nitrogen level, sugar and circadian rhythm.

A full-length coding domain sequence of a gene analogous to granule-bound starch synthase (GBSS; ADP-glucose-starch glucosyltransferase, EC 2.4.1.21) was cloned and defined as OsGBSSII based on a Nitrogen (N)-starvation-induced cDNA library constructed using the rapid subtraction hybridization method. The deduced amino acid sequence of OsGBSSII was 62-85% identical to those of GBSS proteins from other plant species. The exon/intron organization of OsGBSSII was similar to that of OsGBSSI. OsGBSSII was mainly expressed in leaves and its protein was exclusively bound to starch granules in rice leaves, which suggests that the amylose in rice leaves is synthesized by OsGBSSII. N-starvation-induced expression of OsGBSSII could be repressed by supplying nitrate, ammonia or amino acid (glutamic acid or glutamine), glucosamine (an inhibitor of hexokinase) or dark conditions. These results indicate that N-starvation induction was dependent on the photosynthetic product and hexokinase in rice leaves. Sugars induced the accumulation of OsGBSSII transcripts in excised leaves through glycolysis-dependent pathways. OsGBSSII gene expression is regulated by the circadian rhythm in rice leaves.

Amino Acid Sequence↗
PubMed2004

Molecular cloning and expression analysis of three genes encoding starch synthase II in rice.

Three starch synthase (SS) genes, OsSSII-1, OsSSII-2 and OsSSII-3, were identified in rice (Oryza sativa L.) and localized to chromosomes 10, 2 and 6, respectively. The three OsSSII full-length cDNAs were cloned, and the predicted amino acid sequences were found to share 52-73% similarity with other members of the plant SSII family. The SS activity of each OsSSII was confirmed by expression and enzyme activity assay in Escherichia coli. Expression profile analysis revealed that OsSSII-1 was expressed in endosperms, leaves and roots; OsSSII-2 was mainly expressed in leaves, while OsSSII-3 was mainly expressed in endosperms. Similar to the OsSSI proteins, the OsSSII-2 and OsSSII-3 proteins were found in the soluble as well as the starch-granule-bound fractions in rice. The roles of the OsSSII proteins in starch biosynthesis in rice and the evolutionary relationships of the genes encoding monocotyledonous and dicotyledonous class-II SS enzymes are discussed.

Amino Acid Sequence↗
PubMed2004

Antisense inhibition of sorbitol synthesis leads to up-regulation of starch synthesis without altering CO2 assimilation in apple leaves.

Sorbitol is a primary end-product of photosynthesis in apple (Malus domestica Borkh.) and many other tree fruit species of the Rosaceae family. Sorbitol synthesis shares a common hexose phosphate pool with sucrose synthesis in the cytosol. In this study, 'Greensleeves' apple was transformed with a cDNA encoding aldose 6-phosphate reductase (A6PR, EC 1.1.1.200) in the antisense orientation. Antisense expression of A6PR decreased A6PR activity in mature leaves to approximately 15-30% of the untransformed control. The antisense plants had lower concentrations of sorbitol but higher concentrations of sucrose and starch in mature leaves at both dusk and predawn. (14)CO(2) pulse-chase labeling at ambient CO(2) demonstrated that partitioning of the newly fixed carbon to starch was significantly increased, whereas that to sucrose remained unchanged in the antisense lines with decreased sorbitol synthesis. Total activities of ribulose 1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39), sucrose-phosphate synthase (EC 2.4.1.14), and ADP-glucose pyrophosphorylase (EC 2.7.7.27) were not significantly altered in the antisense lines, whereas both stromal and cytosolic fructose-1,6-bisphosphatase (EC 3.1.3.11) activities were higher in the antisense lines with 15% of the control A6PR activity. Concentrations of glucose 6-phosphate and fructose 6-phosphate (F6P) were higher in the antisense plants than in the control, but the 3-phosphoglycerate concentration was lower in the antisense plants with 15% of the control A6PR activity. Fructose 2, 6-bisphosphate concentration increased in the antisense plants, but not to the extent expected from the increase in F6P, comparing sucrose-synthesizing species. There was no significant difference in CO(2) assimilation in response to photon flux density or intercellular CO(2) concentration. We concluded that cytosolic FBPase activity in vivo was down-regulated and starch synthesis was up-regulated in response to decreased sorbitol synthesis. As a result, CO(2) assimilation in source leaves was sustained at both ambient CO(2) and saturating CO(2).

Carbon Dioxide↗