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1

Cyclic AMP and low molecular weight effector(s) present in yeast extract are involved in pectin lyase production by Penicillium griseoroseum cultured on sucrose  

Microsoft Academic Search

Pectin lyase (PL) induction by organic and inorganic components of yeast extract (YE) was evaluated in Penicillum griseoroseum, cultured in a mineral medium containing sucrose, by determining PL activity (A\\u000a 235) and mycelial growth (mycelial dry weight). The lowest YE concentration that promoted significant PL induction without acting\\u000a as a carbon source for the fungus corresponded to 0.0075%. Neither calcined

Maria Cristina Baracat-Pereira; Jorge Luiz Cavalcante Coelho; Rosana Cristina Minussi; Virgínia Maria Chaves-Alves; Rogelio Lopes Brandão; Daison Olzany Silva

1999-01-01

2

Glucose and sucrose: hazardous fast-food for industrial yeast?  

Microsoft Academic Search

Yeast cells often encounter a mixture of different carbohydrates in industrial processes. However, glucose and sucrose are always consumed first. The presence of these sugars causes repression of gluconeogenesis, the glyoxylate cycle, respiration and the uptake of less- preferred carbohydrates. Glucose and sucrose also trigger unexpected, hormone-like effects, including the activation of cellular growth, the mobilization of storage compounds and

Kevin J. Verstrepen; Dirk Iserentant; Philippe Malcorps; Guy Derdelinckx; Patrick Van Dijck; Joris Winderickx; Isak S. Pretorius; Johan M. Thevelein; Freddy R. Delvaux

2004-01-01

3

[Immobilized yeast membranes as biocatalysts for sucrose inversion].  

PubMed

Yeast membranes were obtained by autolysis of various strains with relatively high invertase activity. Heterogeneous biocatalysts for sucrose inversion were made of the yeast membranes and granulated carbon-containing supports made of common natural materials: expanded clay aggregate (ECA), sapropel, and lignin. The properties of these biocatalysts were studied. It was shown that the biocatalyst activity and stability of the immobilized yeast membranes increased with reference to the initial ECA, independent of the structure of the carbon layer synthesized on the support surface. Heterogeneous biocatalysts prepared by adsorption of yeast membranes on sapropel had the greatest activity and stability, whereas lignin-based biocatalysts were relatively unstable. PMID:16212044

Kovalenko, G A; Perminova, L V; Plaksin, G V; Komova, O V; Chuenko, T V; Rudina, N A

2005-01-01

4

Continuous sucrose hydrolysis by yeast cells immobilized to wool.  

PubMed

A novel immobilized biocatalyst with invertase activity was prepared by adhesion of yeast cells to wool using-glutaraldehyde. Yeast cells could be immobilized onto wool by treating either the yeast cells or wool or both with glutaraldehyde. Immobilized cells were not desorbed by washing with 1 M KCl or 0.1 M buffers. pH 3.5-7.5. The biocatalyst shows a maximum enzyme activity when immobilized at pH 4.2-4.6 and 7.5-8.0. The immobilized biocatalyst was tested in a tubular fixed-bed reactor to investigate its possible application for continuous full-scale sucrose hydrolysis. The influence of temperature, sugar concentration and flow rate on the productivity of the reactor and on the specific productivity of the biocatalyst was studied. The system demonstrates a very good productivity at a temperature of 70 degrees C and a sugar concentration of 2.0 M. The increase of the volume of the biocatalyst layer exponentially increases the productivity. The productivity of the immobilized biocatalyst decreases no more than 50% during 60 days of continuous work at 70 degrees C and 2.0 M sucrose, but during the first 30 days it remains constant. The cumulative biocatalyst productivity for 60 days was 4.8 x 10(3) kg inverted sucrose/kg biocatalyst. The biocatalyst was proved to be fully capable of continuous sucrose hydrolysis in fixed-bed reactors. PMID:9210337

Krastanov, A

1997-05-01

5

Sucrose utilization in budding yeast as a model for the origin of undifferentiated multicellularity.  

PubMed

We use the budding yeast, Saccharomyces cerevisiae, to investigate one model for the initial emergence of multicellularity: the formation of multicellular aggregates as a result of incomplete cell separation. We combine simulations with experiments to show how the use of secreted public goods favors the formation of multicellular aggregates. Yeast cells can cooperate by secreting invertase, an enzyme that digests sucrose into monosaccharides, and many wild isolates are multicellular because cell walls remain attached to each other after the cells divide. We manipulate invertase secretion and cell attachment, and show that multicellular clumps have two advantages over single cells: they grow under conditions where single cells cannot and they compete better against cheaters, cells that do not make invertase. We propose that the prior use of public goods led to selection for the incomplete cell separation that first produced multicellularity. PMID:21857801

Koschwanez, John H; Foster, Kevin R; Murray, Andrew W

2011-08-01

6

Sucrose Utilization in Budding Yeast as a Model for the Origin of Undifferentiated Multicellularity  

PubMed Central

We use the budding yeast, Saccharomyces cerevisiae, to investigate one model for the initial emergence of multicellularity: the formation of multicellular aggregates as a result of incomplete cell separation. We combine simulations with experiments to show how the use of secreted public goods favors the formation of multicellular aggregates. Yeast cells can cooperate by secreting invertase, an enzyme that digests sucrose into monosaccharides, and many wild isolates are multicellular because cell walls remain attached to each other after the cells divide. We manipulate invertase secretion and cell attachment, and show that multicellular clumps have two advantages over single cells: they grow under conditions where single cells cannot and they compete better against cheaters, cells that do not make invertase. We propose that the prior use of public goods led to selection for the incomplete cell separation that first produced multicellularity.

H. Koschwanez, John; R. Foster, Kevin; W. Murray, Andrew

2011-01-01

7

Plasma lipid and lipoprotein responses of rats to starch and sucrose diets with and without brewer's yeast.  

PubMed

The effect of starch and sucrose diets, with and without brewer's yeast, on plasma total cholesterol and triglyceride concentration and on the lipoprotein distribution in plasma was studied in male rats. The rats were fed a cereal based stock diet, a starch or a sucrose diet, plus or minus brewer's yeast, for 4 weeks. The plasma cholesterol concentration increased to similar levels in rats fed the starch or the sucrose diets but remained unchanged in rats fed the stock diet. The plasma triglyceride level increased in rats fed stock diet, but was unchanged in those fed starch or sucrose diets. Brewer's yeast did not modify the cholesterol value in any of the three groups but reduced the triglyceride level in rats fed the stock and the starch diets. In rats fed the starch diet there was a reduction in the relative amount of prebeta lipoproteins, but no significant alterations in the beta, prealpha and alpha fractions, as compared with rats fed stock diet. Rats fed the sucrose diet had lower prebeta, beta and alpha lipoprotein percentages and a much higher prealpha percentage than rats fed the stock diet. Brewer's yeast had no consistent effects on the lipoprotein distribution. The results support the contention that there might be a dissociation between dietary effects on the plasma lipid level and on the lipoprotein distribution. PMID:448446

Høstmark, A T; Eilertsen, E; Grønnerød, O

1979-06-01

8

Extraction of lipid membrane incorporated vitamin E by sucrose polyesters.  

PubMed

2H and 31P solid state NMR have been used to probe, at the molecular level, the interaction between structurally different sucrose polyesters and a phospholipid membrane into which alpha-tocopherol and specifically deuterated alpha-[5,7-(2)H(6)] tocopherol has been incorporated. Our results show that at high concentration (>or=10 mol%) sucrose octapalmitate (SOP) and sucrose hexapalmitate (SHxP) deplete bilayer-associated alpha-tocopherol in dipalmitoyl phosphatidalcholine (DPPC) multilamellar dispersions and preferentially sequester the alpha-tocopherol into a fluid sucrose polyesters (SPE) phase located proximal to the membrane surface. It is demonstrated that the ability of SPEs to function as a 'lipophilic sink' depends strongly on sucrose polyester concentration and degree of esterification. PMID:11518572

McManus, G G; Buchanan, G W; Jarrell, H C

2001-07-01

9

The effect of sucrose on the quality of ryegrass (Lolium perenne) pollen extracts.  

PubMed

We studied the protein-stabilizing properties of sucrose, in the extraction medium, on the composition and stability of ryegrass (Lolium perenne) pollen extracts. The effect of 0.5 M and 1 M sucrose was assessed in the presence and absence of 0.5% phenol, which is commonly used as a disinfectant in industrially prepared allergenic extracts. In the absence of phenol, sucrose improves the stability of extracts during storage, but it has little influence on the extraction process. In the presence of 0.5% phenol, however, both the quality of fresh extracts and the stability are greatly improved by 0.5 M and by 1 M sucrose, as shown by electrophoresis, immunoblotting, and RAST-inhibition experiments. The protection afforded by sucrose against the degrading effect of phenol is particularly evident for the major allergen Lol p 1 and for a set of basic allergens. In this respect, sucrose has been found to be superior to glycerol, on an equimolar basis. One may envisage the use of 0.5 M sucrose in allergenic extracts for intradermal testing and immunotherapy. PMID:8834822

Cadot, P; Lejoly, M; Stevens, E A

1995-12-01

10

Preparation of extracts from yeast.  

PubMed

Because yeast is exceptionally well suited to genetic analysis, both classical and molecular, it is an attractive system for expressing recombinant animal proteins for purification purposes. Methods available for lysing yeast cells include autolysis, pressure cells (e.g., French press), abrasives (glass bead vortexing), and enzymatic lysis (e.g., zymolase). One of the simplest methods, discussed in this protocol, involves the abrasive action of well-agitated glass beads. This is a very effective method for both low volumes (e.g., <1 mL using a microcentrifuge tube) and many liters using a specialized DynoMill apparatus. Cell breakage is typically >95%, as assessed by phase-contrast microscopy. PMID:21205845

Simpson, Richard J

2011-01-01

11

Games microbes play: The game theory behind cooperative sucrose metabolism in yeast  

NASA Astrophysics Data System (ADS)

The origin of cooperation is a central challenge to our understanding of evolution. Microbial interactions can be manipulated in ways that animal interactions cannot, thus leading to growing interest in microbial models of cooperation and competition. In order for the budding yeast S. cerevisiae to grow on sucrose, the disaccharide must first be hydrolyzed by the enzyme invertase. This hydrolysis reaction is performed outside of the cytoplasm in the periplasmic space between the plasma membrane and the cell wall. Here we demonstrate that the vast majority (˜99%) of the monosaccharides created by sucrose hydrolysis diffuse away before they can be imported into the cell, thus making invertase production and secretion a cooperative behavior [1]. A mutant cheater strain that does not produce invertase is able to take advantage of and invade a population of wildtype cooperator cells. However, over a wide range of conditions, the wildtype cooperator can also invade a population of cheater cells. Therefore, we observe coexistence between the two strains in well-mixed culture at steady state resulting from the fact that rare strategies outperform common strategies---the defining features of what game theorists call the snowdrift game. A simple model of the cooperative interaction incorporating nonlinear benefits explains the origin of this coexistence. Glucose repression of invertase expression in wildtype cells produces a strategy which is optimal for the snowdrift game---wildtype cells cooperate only when competing against cheater cells. In disagreement with recent theory [2], we find that spatial structure always aids the evolution of cooperation in our experimental snowdrift game. [4pt] [1] Gore, J., Youk, H. & van Oudenaarden, A., Nature 459, 253 -- 256 (2009) [0pt] [2] Hauert, C. & Doebeli, M., Nature 428, 643 -- 646 (2004)

Gore, Jeff

2010-03-01

12

SUC1 and SUC2: two sucrose transporters from Arabidopsis thaliana; expression and characterization in baker's yeast and identification of the histidine-tagged protein  

Microsoft Academic Search

Summary An important, most likely essential step for the long distance transport of sucrose in higher plants is the energy-dependent, uncoupler-sensiUve loading into phloem cells via a sucrose-H + symporter. This paper describes functional expression in Saccharomyces cerevisiae of two cDNAs encoding energy-dependent sucrose transporters from the plasma membrane of Arabidopsis thaliane, SUCl and SUC2. Yeast cells transformed with vectors

Norbert Sauer; JLirgen Stolz

1994-01-01

13

Citric acid production from sucrose using a recombinant strain of the yeast Yarrowia lipolytica.  

PubMed

The yeast Yarrowia lipolytica is able to secrete high amounts of several organic acids under conditions of growth limitation and carbon source excess. Here we report the production of citric acid (CA) in a fed-batch cultivation process on sucrose using the recombinant Y. lipolytica strain H222-S4(p67ICL1) T5, harbouring the invertase encoding ScSUC2 gene of Saccharomyces cerevisiae under the inducible XPR2 promoter control and multiple ICL1 copies (10-15). The pH-dependent expression of invertase was low at pH 5.0 and was identified as limiting factor of the CA-production bioprocess. The invertase expression was sufficiently enhanced at pH 6.0-6.8 and resulted in production of 127-140 g l(-1) CA with a yield Y (CA) of 0.75-0.82 g g(-1), whereas at pH 5.0, 87 g l (-1) with a yield Y (CA) of 0.51 g g(-1) were produced. The CA-productivity Q (CA) increased from 0.40 g l (-1) h(-1) at pH 5.0 up to 0.73 g l (-1) h(-1) at pH 6.8. Accumulation of glucose and fructose at high invertase expression level at pH 6.8 indicated a limitation of CA production by sugar uptake. The strain H222-S4(p67ICL1) T5 also exhibited a gene-dose-dependent high isocitrate lyase expression resulting in strong reduction (<5%) of isocitric acid, a by-product during CA production. PMID:17447058

Förster, André; Aurich, Andreas; Mauersberger, Stephan; Barth, Gerold

2007-07-01

14

The inhibitory effects of mushroom extracts on sucrose-dependent oral biofilm formation.  

PubMed

Mushrooms contain large quantities of alpha-glucans. Shiitake (Lentinula edodes), Japan's most popular edible mushroom, has been reported to contain about 6% (weight/dried weight) of alpha-(1,3)-glucan. This glucan is one of the major components of oral biofilm formed by the cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus. We found that extracts from shiitake and other edible mushrooms could reduce preformed biofilms of S. mutans and S. sobrinus in the presence of dextranase. We also investigated the alpha-glucanase activities of shiitake mushroom extracts and their effects on biofilm formation. The extracts possessed alpha-glucanase activity and degraded water-insoluble glucans from mutans streptococci. The extracts strongly inhibited the sucrose-dependent formation of biofilms by S. mutans and S. sobrinus in the presence of dextranase. Our results suggest that some components of mushrooms, including alpha-glucanases, might inhibit the sucrose-induced formation of oral biofilms. PMID:19902205

Yano, Akira; Kikuchi, Sayaka; Yamashita, Yoshihisa; Sakamoto, Yuichi; Nakagawa, Yuko; Yoshida, Yasuo

2010-03-01

15

21 CFR 172.590 - Yeast-malt sprout extract.  

Code of Federal Regulations, 2010 CFR

...conditions: (a) The additive is produced by partial hydrolysis of yeast extract (derived from Saccharomyces cereviseae, Saccharomyces fragilis, or Candida utilis ) using the sprout portion of malt barley as the source of...

2009-04-01

16

21 CFR 172.590 - Yeast-malt sprout extract.  

Code of Federal Regulations, 2013 CFR

...additive is produced by partial hydrolysis of yeast extract (derived from Saccharomyces cereviseae, Saccharomyces fragilis, or Candida utilis ) using the sprout portion of malt barley as the source of enzymes. The additive contains a maximum of 6 percent...

2013-04-01

17

The Influence of Exogenous Nutrients on the Abundance of Yeasts on the Phylloplane of Turfgrass  

Microsoft Academic Search

Four experiments were conducted to assess the effect of foliar applications of various nutrient solutions on the phylloplane\\u000a yeast community of tall fescue (Festuca arundinacea Schreb.). In the first three experiments, increasing concentrations of sucrose (2–16%), yeast extract (0.5–2.5%), and sucrose\\u000a plus yeast extract (2.5–18.5% total) were applied and the yeast colony forming units (cfu) enumerated 14 h later by dilution

Shannon Nix-Stohr; Leon L. Burpee; James W. Buck

2008-01-01

18

Downstream process for the production of yeast extract using brewer's yeast cells  

Microsoft Academic Search

A downstream process was developed for the production of yeast extract from brewer's yeast cells. Various downstream processing\\u000a conditions including clarification, debittering, and the Maillard reaction were considered in the development of the process.\\u000a This simple and economic clarification process used flocculating agents, specifically calcium chloride (1%). After the clarification\\u000a step, a Maillard reaction is initiated as a flavor-enhancing step.

Man-Jin In; Dong Chung Kim; Hee Jeong Chae

2005-01-01

19

Tris-sucrose buffer system: a new specially designed medium for extracellular invertase production by immobilized cells of isolated yeast Cryptococcus laurentii MT-61.  

PubMed

The aims of the present study were to isolate new yeasts with high extracellular (exo) invertase activity and to investigate the usability of buffer systems as invertase production media by immobilized yeast cells. Among 70 yeast isolates, Cryptococcus laurentii MT-61 had the highest exo-invertase activity. Immobilization of yeast cells was performed using sodium alginate. Higher exo-invertase activity for immobilized cells was achieved in tris-sucrose buffer system (TSBS) compared to sodium acetate buffer system and potassium phosphate buffer system. TSBS was prepared by dissolving 30 g of sucrose in 1 L of tris buffer solution. The optimum pH, temperature, and incubation time for invertase production with immobilized cells were determined as 8.0, 35 °C and 36 h in TSBS, respectively. Under optimized conditions, maximum exo-invertase activity was found to be 28.4 U/mL in sterile and nonsterile TSBS. Immobilized cells could be reused in 14 and 12 successive cycles in sterile and nonsterile TSBS without any loss in the maximum invertase activity, respectively. This is the first report which showed that immobilized microbial cells could be used as a biocatalyst for exo-invertase production in buffer system. As an additional contribution, a new yeast strain with high invertase activity was isolated. PMID:23722276

Aydogan, Mehmet Nuri; Taskin, Mesut; Canli, Ozden; Arslan, Nazli Pinar; Ortucu, Serkan

2014-01-01

20

40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Yeast Extract Hydrolysate from Saccharomyces cerevisiae...Tolerances § 180.1246 Yeast Extract Hydrolysate from Saccharomyces cerevisiae...the biochemical pesticide Yeast Extract Hydrolysate from Saccharomyces...

2013-07-01

21

Production of ethanol by filamentous and yeast-like forms of Mucor indicus from fructose, glucose, sucrose, and molasses  

Microsoft Academic Search

The fungus Mucor indicus is found in this study able to consume glucose and fructose, but not sucrose in fermentation of sugarcane and sugar beet\\u000a molasses. This might be an advantage in industries which want to selectively remove glucose and fructose for crystallisation\\u000a of sucrose present in the molasses. On the other hand, the fungus assimilated sucrose after hydrolysis by

Mahnaz Sharifia; Keikhosro Karimi; Mohammad J. Taherzadeh

2008-01-01

22

A rapid and simple method for extracting yeast mitochondrial DNA  

Microsoft Academic Search

A rapid method for the extraction of yeast mitochondrial DNA (mtDNA) is described. In comparison with previous methods, it simplifies several steps, does not require either the isolation of mitochondria or phenol treatment and is less time consuming. This protocol gives a high yield of pure mtDNA (50–120 µg from a 100-ml culture), which can be directly used in various

Ali Gargouri; M. Curie

1989-01-01

23

Molecular Structure of Sucrose  

NSDL National Science Digital Library

Sucrose is the chemical name of table sugar. It is found in granulated, powdered and brown sugar and molasses, as well as, in a variety of fruits and vegetables. Sucrose is a disaccharide that can be made from the combination of two monosaccarides, glucose and fructose. For production use, sucrose is generally extracted from a sugar cane and then purified and crystallized. Sucrose is the most common sweetener in the modern world, however, including too much of it in a diet does have adverse health effects such obesity caused by the high calorie content.

2002-08-29

24

Malolactic bioconversion using a Oenococcus oeni strain for cider production: effect of yeast extract supplementation  

Microsoft Academic Search

Yeast extract addition to reconstituted apple juice had a positive impact on the development of the malolactic starter culture used to ensure malolactic fermentation in cider, using active but non-proliferating cells. In this work, the reuse of fermentation lees from cider is proposed as an alternative to the use of commercial yeast extract products. Malolactic enzymatic assays, both in whole

Mónica Herrero; Luis A. García; Mario Díaz

2003-01-01

25

The effects of different yeast extracts on secondary metabolite production in Fusarium.  

PubMed

Yeast extract is an important constituent in several media used for metabolite profiling of filamentous fungi. The nutrient composition can vary between brands and thereby influence production of secondary metabolites, which can be regulated in response to nitrogen, carbon and pH. In the present study we examined the production of known secondary metabolites in Fusarium pseudograminearum, Fusarium graminearum, Fusarium avenaceum and Fusarium fujikuroi and in each species we identified several secondary metabolites which are influenced by yeast extract brands. Deoxynivalenol and zearalenone were produced in high levels on some yeast extract by F. pseudograminearum and F. graminearum, while absent on others. Chlamydosporol, 2-AOD-3-ol and enniatins were influenced by yeast extracts in F. avenaceum, while bikaverin, gibberellic acid, fumonisin and fusaric acid were affected in F. fujikuroi. Aurofusarin and fusarin C on the other hand were not affected by yeast extracts in all producing strains. The observed differences in production in metabolite profiles show the need to use the same yeast extract brand in repeating experiments. The study illustrates furthermore that it can be beneficial to use more than one yeast extract in metabolite profiling a species. PMID:24291181

Sørensen, Jens Laurids; Sondergaard, Teis Esben

2014-01-17

26

Acidifying and yeast extract in diets for adults cats.  

PubMed

This study evaluated the effects of adding an acidifying agent based on phosphoric acid (A), a yeast extract from a specific strain (Saccharomyces cerevisiae) (Y) and the combination of these two additives in food for adult cats. A test was conducted with 24 animals (mean 3.5 years old), mixed breed, weighing 3.72 ± 0.74 kg, kept in individual metabolic cages and distributed in a completely randomized design with a 2 × 2 factorial design (with or without A 0.6% of dry matter, with or without Y 1.5% of dry matter) totalling four treatments and six replicates of each condition. The experimental period was 15 days. The A or the Y reduced (P< 0.01) the dry matter intake, but the effect was not observed when they were associated. The association improved (P<0.05) the digestibility of dry matter and ashes. The A reduced urine pH (P=0.05) regardless of the presence of the Y. There was no effect (P>0.09) on other parameters evaluated. Results of this study show that the isolated use of 0.6% A or 1.5% Y in diets for cats is not recommended. However, the association of these two additives was beneficial in increasing nutrient digestibility. PMID:24450338

Ogoshi, Rosana C S; Zangeronimo, Márcio G; Dos Reis, Jéssica S; França, Janine; Santos, João P F; Pires, Carolina P; Chizzotti, Ana F; Costa, Adriano C; Ferreira, Lívia G; Saad, Flávia M O B

2014-05-01

27

Effect of yeast extract on growth kinetics during aerobic biodegradation of chlorobenzoic acids  

SciTech Connect

The Monod or Andrews kinetic parameters describing the growth of Pseudomonas sp. CPE2 strain on 2,5-dichlorobenzoic acid and 2-chlorobenzoic acid, and Al-caligenes sp. CPE3 strain on 3,4-dichlorobenzoic acid, 4-chlorobenzoic acid, and 3-chlorobenzoic acid were determined from batch and continuous growth experiments conducted in the presence or absence of yeast extract (50 mg/L). Strain CPE2 displayed inhibitory growth kinetics in the absence of yeast extract and a noninhibitory kinetics in the presence of yeast extract. Similar results were obtained for CPE3. The presence of yeast extract also resulted in a significant increase in the affinity of the strains for the chlorobenzoic acids they degraded.

Armenante, P.M. [New Jersey Inst. of Tech., Newark, NJ (United States). Dept. of Chemical Engineering, Chemistry, and Environmental Science; Fava, F. [Univ. di Bologna (Italy). Dept. of Applied Chemistry and Material Science; Kafkewitz, D. [Rutgers, The State Univ. of New Jersey, Newark, NJ (United States). Dept. of Biological Sciences

1995-07-20

28

Comparison of three buffers used in the formulation of buffered charcoal yeast extract medium.  

PubMed

Growth of Legionella spp. on buffered charcoal yeast extract medium supplemented with alpha-ketoglutarate and formulated with 3-(n-morpholino)propanesulfonic acid (MOPS), 3-(n-morpholino)-2-hydroxypropanesulfonic acid (MOPSO), or n-(2-acetamido)-2-aminoethanesulfonic acid (ACES) buffer was similar. With three exceptions, growth was no different in buffered yeast extract broth supplemented with alpha-ketoglutarate and formulated with MOPS or ACES buffer. PMID:8308131

Edelstein, P H; Edelstein, M A

1993-12-01

29

Ammonia production from yeast extract and its effect on growth of the hyperthermophilic archaeon Sulfolobus solfataricus  

Microsoft Academic Search

Utilization of yeast extract and formation of byproduct metabolite were investigated for hyperthermophilic archaeonSulfolobus solfataricus (DSM 1617). In both batch and fed-batch cultivations ofS. solfataricus, maximal cell density, NH4\\u000a + ion production and pH change were highly dependent on the ratio of yeast extract to glucose in the medium. Variation of NH4\\u000a + ion level was identified as a major

Chan Beum Park; Sun Bok Lee

1998-01-01

30

Terverticillate penicillia studied by direct electrospray mass spectrometric profiling of crude extracts. I. Chemosystematics  

Microsoft Academic Search

A chemosystematic study of 339 isolates from all known terverticillate Penicillium taxa was performed using electrospray mass spectrometric analysis of extractable metabolites. The mass profiles were made by injecting crude plug extracts made from cultures grown on Czapek Yeast Autolysate agar (CYA) and Yeast Extract Sucrose agar (YES) directly into the electrospray source of the mass spectrometer. A data matrix

Jørn Smedsgaard; Jens Christian Frisvad

1997-01-01

31

Selection of yeasts for single cell protein production on media based on Jerusalem artichoke extracts.  

PubMed

Several yeast strains can grow with good yield (0.16 to 0.19 mg protein/mg carbohydrate) on nitrogen supplemented Jerusalem artichoke extract. The most promising strain is Lipomyces starkeyi. Including by-products (pulps, proteins of extract), protein production can reach 2 metric tons/ha. PMID:6613165

Apaire, V; Guiraud, J P; Galzy, P

1983-01-01

32

Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance.  

PubMed

There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema. PMID:17291738

Weckesser, S; Engel, K; Simon-Haarhaus, B; Wittmer, A; Pelz, K; Schempp, C M

2007-08-01

33

Kefir-yeast technology: Industrial scale-up of alcoholic fermentation of whey, promoted by raisin extracts, using kefir-yeast granular biomass  

Microsoft Academic Search

Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cells is reported. The fermented whey would be exploited as raw material to produce kefir-like whey-based drinks, potable and fuel alcohol, as well as kefir-yeast biomass for use as baker's yeast. The scale-up process involved the development of a technology transfer scheme from lab-scale experiments to a successive

Athanasios A. Koutinas; Ilias Athanasiadis; Argyro Bekatorou; Costas Psarianos; Maria Kanellaki; Nikolaos Agouridis; Georgios Blekas

2007-01-01

34

21 CFR 184.1983 - Bakers yeast extract.  

Code of Federal Regulations, 2013 CFR

...The viable microbial content of the finished ingredient as a concentrate or dry material is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E....

2013-04-01

35

Separation of astaxanthin from red yeast Phaffia rhodozyma by supercritical carbon dioxide extraction  

Microsoft Academic Search

The supercritical fluid extraction (SFE) behavior was investigated to extract astaxanthin from the red yeast Phaffia rhodozyma, which was disrupted and dried by bead mill and spray dryer, respectively. The effects of extraction pressure (102–500bar), temperature (40, 60 and 80°C), CO2 flow rate (superficial velocities of 0.27 and 0.54cm\\/min) and the use of ethyl alcohol as a modifier (1, 5,

Gio-Bin Lim; Sang-Yun Lee; Eun-Kyu Lee; Seung-Joo Haam; Woo-Sik Kim

2002-01-01

36

Cottonseed extract versus pharmamedia for the in vitro mould-yeast conversion of Blastomyces dermatitidis.  

PubMed

A cottonseed medium, based on a 1% aqueous extract of seeds of any of the eight indigenously available varieties of cotton belonging to Gossypium hirsutum or Gossypium arboreum, was evaluated for the mould-yeast conversion of Blastomyces dermatitidis in vitro, and compared with pharmamedia agar as a control. The cottonseed agar was found to be as efficient as pharmamedia agar for the mould-yeast conversion of the 19 B. dermatitidis strains tested. Therefore, cottonseeds provide an adequate and inexpensive substitute for pharmamedia for the mould-yeast conversion of B. dermatitidis. It should be noted that the term 'cottonseed' medium has been used rather loosely in the literature and that this medium is based on pharmamedia and not on a cottonseed extract. The authors suggest that media based on pharmamedia should be referred to as pharmamedia agar and the use of the term 'cottonseed' should be restricted to media containing cottonseed extract. PMID:2380881

Chaturvedi, S; Randhawa, H S; Chaturvedi, V P; Khan, Z U

1990-01-01

37

Obtaining and selection of hexokinases-less strains of Saccharomyces cerevisiae for production of ethanol and fructose from sucrose.  

PubMed

Saccharomyces cerevisiae hexokinase-less strains were produced to study the production of ethanol and fructose from sucrose. These strains do not have the hexokinases A and B. Twenty-three double-mutant strains were produced, and then, three were selected for presenting a smaller growth in yeast extract-peptone-fructose. In fermentations with a medium containing sucrose (180.3 g L(-1)) and with cell recycles, simulating industrial conditions, the capacity of these mutant yeasts in inverting sucrose and fermenting only glucose was well characterized. Besides that, we could also see their great tolerance to the stresses of fermentative recycles, where fructose production (until 90 g L(-1)) and ethanol production (until 42.3 g L(-1)) occurred in cycles of 12 h, in which hexokinase-less yeasts performed high growth (51.2% of wet biomass) and viability rates (77% of viable cells) after nine consecutive cycles. PMID:18008068

Carvalho, Rodrigo Setem; Gomes, Luiz Humberto; Gonzaga do P Filho, Luiz; Tavares, Flávio C A

2008-01-01

38

Chromatin assembly in a yeast whole-cell extract  

PubMed Central

A simple in vitro system that supports chromatin assembly was developed for Saccharomyces cerevisiae. The assembly reaction is ATP-dependent, uses soluble histones and assembly factors, and generates physiologically spaced nucleosomes. We analyze the pathway of histone recruitment into nucleosomes, using this system in combination with genetic methods for the manipulation of yeast. This analysis supports the model of sequential recruitment of H3/H4 tetramers and H2A/H2B dimers into nucleosomes. Using a similar approach, we show that DNA ligase I can play an important role in template repair during assembly. These studies demonstrate the utility of this system for the combined biochemical and genetic analysis of chromatin assembly in yeast.

Schultz, Michael C.; Hockman, Darren J.; Harkness, Troy A. A.; Garinther, Wendy I.; Altheim, Brent A.

1997-01-01

39

Chromatin assembly in a yeast whole-cell extract.  

PubMed

A simple in vitro system that supports chromatin assembly was developed for Saccharomyces cerevisiae. The assembly reaction is ATP-dependent, uses soluble histones and assembly factors, and generates physiologically spaced nucleosomes. We analyze the pathway of histone recruitment into nucleosomes, using this system in combination with genetic methods for the manipulation of yeast. This analysis supports the model of sequential recruitment of H3/H4 tetramers and H2A/H2B dimers into nucleosomes. Using a similar approach, we show that DNA ligase I can play an important role in template repair during assembly. These studies demonstrate the utility of this system for the combined biochemical and genetic analysis of chromatin assembly in yeast. PMID:9256430

Schultz, M C; Hockman, D J; Harkness, T A; Garinther, W I; Altheim, B A

1997-08-19

40

Chromatin Assembly in a Yeast Whole-Cell Extract  

NASA Astrophysics Data System (ADS)

A simple in vitro system that supports chromatin assembly was developed for Saccharomyces cerevisiae. The assembly reaction is ATP-dependent, uses soluble histones and assembly factors, and generates physiologically spaced nucleosomes. We analyze the pathway of histone recruitment into nucleosomes, using this system in combination with genetic methods for the manipulation of yeast. This analysis supports the model of sequential recruitment of H3/H4 tetramers and H2A/H2B dimers into nucleosomes. Using a similar approach, we show that DNA ligase I can play an important role in template repair during assembly. These studies demonstrate the utility of this system for the combined biochemical and genetic analysis of chromatin assembly in yeast.

Schultz, Michael C.; Hockman, Darren J.; Harkness, Troy A. A.; Garinther, Wendy I.; Altheim, Brent A.

1997-08-01

41

Repeated fed-batch rapid fermentation using yeast cells and activated carbon extraction system  

SciTech Connect

The application of a repeated fed-batch rapid ethanol fermentation employing immobilized yeast cells accompanied by an activated carbon extraction system has been investigated in an attempt to increase product yield. Immobilized and free yeast cells were used to effect ethanol fermentations in a simplified nitrogen-free medium containing only glucose and mineral salts. Repeatedly, fermentation broth with a high ethanol concentration (80 to 100 g/L) was extracted using activated carbon beads (BACM) and the resulting broth of low ethanol content (< 50 g/L) was recycled back for further fermentations. The maximum ethanol productivity achieved in this system was 25 g/L/h. 7 figures, 1 table.

Lee, S.S.; Wang, H.Y.

1982-01-01

42

Comparison of different methods for extraction of mitochondrial DNA from human pathogenic yeasts.  

PubMed

Methods of rapidly extracting chromosomal DNA from human pathogenic yeasts were used in mitochondrial DNA (mtDNA) studies. This paper is concerned with rapid and reliable methods of extracting mtDNA for sequence analysis for species or strain identification, and epidemiological study of medically important fungi and fungal infections. To determine the optimal method of mtDNA extraction without isolating mitochondria, we examined three commonly used methods: 1). boiling, 2). glass bead disruption, and 3). a commercially available kit. We assessed the amount and quality of DNAs using a spectrophotometer and specific polymerase chain reaction (PCR). The DNA yield depended on the extraction method used and the yeast species. An adequate amount of mtDNA was obtained with both glass beads and a commercially available kit to amplify the mitochondrial gene using PCR without isolating the mitochondria. These techniques are convenient for extracting DNA from a variety of small-scale samples. PMID:12403909

Yamada, Yohko; Makimura, Koichi; Merhendi, Hossain; Ueda, Kumiko; Nishiyama, Yayoi; Yamaguchi, Hideyo; Osumi, Masako

2002-08-01

43

Use of an alkali-soluble water-soluble extract of Blastomyces dermatitidis yeast-phase cell walls and isoelectrically focused components in peripheral lymphocyte transformations.  

PubMed Central

An alkali-soluble water-soluble extract of Blastomyces dermatitidis yeast-phase cell walls was tested for its ability to elicit a response in lymphocytes isolated from the peripheral blood of Blastomyces-infected guinea pigs. Sequential preparations of the antigen were reproducible and specific in the in vitro lymphocyte transformation assay. Cross-reactivity of the antigen was not evident in lymphocyte transformation assays on lymphocytes obtained from Histoplasma-infected guinea pigs or from animals sensitized with complete Freund adjuvant. Fractionation of the antigen was accomplished on an isoelectric-focusing column, using a sucrose density gradient support. Components were assayed for activity in skin testing and lymphocyte transformation. Comparison of column fractions to the whole antigen showed greater response to the whole antigen in in vivo and in vitro assays.

Hall, N K; Deighton, F; Larsh, H W

1978-01-01

44

Effect of yeast extract on glucoamylase synthesis by Aspergillus awamori NRRL 3112  

Microsoft Academic Search

Summary Glucoamylase synthesis is strongly affected by yeast extract concentration (CE). An eight fold increase in CE caused a two fold increase in the maximum glucoamylase activity value (Am) for the cultivations conducted with an initial glucose concentration (GO) of about 20 g\\/l, and a four fold increase in Am in the runs with a Go value of about 40

Maria Cândida R. Facciotti; Gerson H. Wuhstrack; Aldo Tonso; Miriam L. Chiquetto; Willibaldo Schmidell

1991-01-01

45

Effects of dietary yeast extract on turkey stress response and heterophil oxidative burst activity  

Microsoft Academic Search

1. Effective nutritional approaches to counteract the negative effects of stress may provide food animal producers with useful alternatives to antibiotics. In this study, turkeys were fed on a standard diet, or the same diet supplemented with yeast extract (YE), to determine if YE would improve disease resistance in a stress model.2. At 16 weeks of age, half of the

G. R. Huff; V. Dutta; W. E. Huff; N. C. Rath

2011-01-01

46

Utilization capability of sucrose, raffinose and inulin and its less-sensitiveness to glucose repression in thermotolerant yeast Kluyveromyces marxianus DMKU 3-1042  

PubMed Central

Kluyveromyces marxianus possesses a useful potential to assimilate a wide variety of substrates at a high temperature, but the negative effect by coexisting glucose is critical for utilization of biomass containing various sugars. Such a negative effect on the activity of inulinase, which is the sole enzyme to hydrolyze sucrose, raffinose and inulin, has been demonstrated in K. marxianus without analysis at the gene level. To clarify the utilization capability of sucrose, raffinose and inulin and the glucose effect on inulinase in K. marxianus DMKU 3-1042, its growth and metabolite profiles on these sugars were examined with or without glucose under a static condition, in which glucose repression evidently occurs. Consumption of sucrose was not influenced by glucose or 2-deoxyglucose. On the other hand, raffinose and inulin consumption was hampered by glucose at 30°C but hardly hampered at 45°C. Unlike Saccharomyces cerevisiae, increase in glucose concentration had no effect on sucrose utilization. These sugar-specific glucose effects were consistent with the level of inulinase activity but not with that of the KmINU1 transcript, which was repressed in the presence of glucose via KmMig1p. This inconsistency may be due to sufficient activity of inulinase even when glucose is present. Our results encourage us to apply K. marxianus DMKU 3-1042 to high-temperature ethanol fermentation with biomass containing these sugars with glucose.

2011-01-01

47

Yeast extract, brewer’s yeast and spirulina in diets for Labeo rohita fingerlings affect haemato-immunological responses and survival following Aeromonas hydrophila challenge  

Microsoft Academic Search

A feeding trial was conducted for 60days to study the immunomodulatory role of three different immunostimulants yeast extract (YE), brewer’s yeast (BY) and spirulina (SP) in Labeo rohita fingerlings. Four hundred and fifty fingerlings (avg. wt 3.35±0.15g) were randomly distributed in ten treatments and fed with either of ten iso-nitrogenous and iso-caloric semi-purified diets, prepared with three incremental levels (1%,

Simi Rose Andrews; N. P. Sahu; A. K. Pal; S. C. Mukherjee; Shivendra Kumar

2011-01-01

48

Dextransucrase production using cashew apple juice as substrate: effect of phosphate and yeast extract addition.  

PubMed

Cashew apples are considered agriculture excess in the Brazilian Northeast because cashew trees are cultivated primarily with the aim of cashew nut production. In this work, the use of cashew apple juice as a substrate for Leuconostoc mesenteroides cultivation was investigated. The effect of yeast extract and phosphate addition was evaluated using factorial planning tools. Both phosphate and yeast extract addition were significant factors for biomass growth, but had no significant effect on maximum enzyme activity. The enzyme activities found in cashew apple juice assays were at least 3.5 times higher than the activity found in the synthetic medium. Assays with pH control (pH = 6.5) were also carried out. The pH-controlled fermentation enhanced biomass growth, but decreased the enzyme activity. Crude enzyme free of cells produced using cashew apple juice was stable for 16 h at 30 degrees C at a pH of 5.0. PMID:17323142

Chagas, Clarice M A; Honorato, Talita L; Pinto, Gustavo A S; Maia, Geraldo A; Rodrigues, Sueli

2007-05-01

49

Sequential extraction leading to improved proteomic analysis of the oleaginous yeast Lipomyces starkeyi.  

PubMed

The oleaginous yeast Lipomyces starkeyi (L. starkeyi) is an excellent intracellular lipid producer. Thus, extraction of protein from lipid-rich L. starkeyi samples following conventional methods can be difficult, leading to poor data in terms of proteomic analysis. The presence of lipophilic components in those samples may also interfere with the extraction process and the downstream analysis. In this work, we developed a sequential extraction method for preparation and analysis of L. starkeyi proteome combining to an online multidimensional nano reversed-phase liquid chromatography-tandem mass spectrometry (microRPLC-MS/MS) strategy. Protein hits of high confidence reached 227 with false positive rate less than 0.1, twice of those identified from the one-buffer extraction preparation. Moreover, the protein hits related to primary metabolism was increased, which may be important to establish the molecular mechanism of lipid accumulation. The method should be valuable for protein extraction from oleaginous species. PMID:21847969

Liu, Hongwei; Zhao, Xin; Cheng, Kai; Zhao, Zongbao; Ye, Mingliang

2011-05-01

50

Ultrasound assisted extraction of carbohydrates from microalgae as feedstock for yeast fermentation.  

PubMed

Recently, carbohydrates biomass from microalgae is considered as a promising and inexpensive feedstock for biofeuls production by microorganism fermentation. The main obstacle of the process is microalgae pretreatment and carbohydrates extraction from algal cell. In this study, comparison of three pretreatment methods was performed and the results showed that ultrasonic assisted extraction (UAE) was very effective. The effects of four parameters (ultrasonic power, extraction time, flow rate and algal cell concentration, respectively) on extraction efficiency were also investigated. Additionally, in order to identify significant factors for glucose yield, combination of these four parameters was examined by using fractional factorial design (FFD) and the regression model was obtained. Meanwhile, the refined model was confirmed as a good fitting model via analysis of variance (ANOVA). After extraction, glucose obtained from microalgae was used as substrate for Rhodosporidium toruloides fermentation and yeast biomass was much higher than that of control culture. PMID:23196255

Zhao, Guili; Chen, Xue; Wang, Lei; Zhou, Shixiao; Feng, Huixing; Chen, Wei Ning; Lau, Raymond

2013-01-01

51

The extraction of liquid, protein molecules and yeast cells from paper through surface acoustic wave atomization.  

PubMed

Paper has been proposed as an inexpensive and versatile carrier for microfluidics devices with abilities well beyond simple capillary action for pregnancy tests and the like. Unlike standard microfluidics devices, extracting a fluid from the paper is a challenge and a drawback to its broader use. Here, we extract fluid from narrow paper strips using surface acoustic wave (SAW) irradiation that subsequently atomizes the extracted fluid into a monodisperse aerosol for use in mass spectroscopy, medical diagnostics, and drug delivery applications. Two protein molecules, ovalbumin and bovine serum albumin (BSA), have been preserved in paper and then extracted using atomized mist through SAW excitation; protein electrophoresis shows there is less than 1% degradation of either protein molecule in this process. Finally, a solution of live yeast cells was infused into paper, which was subsequently dried for preservation then remoistened to extract the cells via SAW atomization, yielding live cells at the completion of the process. The successful preservation and extraction of fluids, proteins and yeast cells significantly expands the usefulness of paper in microfluidics. PMID:20126687

Qi, Aisha; Yeo, Leslie; Friend, James; Ho, Jenny

2010-02-21

52

Effectiveness of modified yeast cell wall extracts to reduce aflatoxin B1 absorption in dairy ewes  

Microsoft Academic Search

This study investigated the effect of a modified yeast cell wall extract preparation (YCW) on the excretion of aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) in feces, urine, and milk of dairy ewes fed an aflatoxin-contaminated diet. Sixteen ewes in mid-lactation were assigned to 4 treatment groups: control, AF (60?g of AFB1\\/kg of feed), YCW (2g\\/kg of feed), and AF+YCW.

S. Firmin; D. P. Morgavi; A. Yiannikouris; H. Boudra

2011-01-01

53

Semiconservative replication in yeast nuclear extracts requires Dna2 helicase and supercoiled template1  

Microsoft Academic Search

We describe the preparation of nuclear extracts from yeast cells synchro- nised in S-phase that support the aphidicolin-sensitive, semi-conservative replication of primer-free, supercoiled plasmid in vitro. This is monitored by one and two-dimensional gel electrophoresis of replication intermedi- ates that have incorporated (a- 32 P)dATP, by the conversion of methylated template DNA into a hemi-methylated or DpnI-resistant form, and by

D. Braguglia; P. Heun; P. Pasero; B. P Duncker; S. M Gasser

1998-01-01

54

Induction of rosmarinic acid biosynthesis in Lithospermum erythrorhizon cell suspension cultures by yeast extract  

Microsoft Academic Search

A transient increase in rosmarinic acid (RA) content in cultured cells of Lithospermum erythrorhizon was observed after addition of yeast extract (YE) to the suspension cultures, reaching a maximum at 24 hr. The highest increase of the RA content (2.5-fold) was obtained when 6-day-old cells in the exponential growth phase were treated with YE. Preceding the induced RA accumulation, phenylalanine

Hajime Mizukami; Terumi Ogawa; Hiromu Ohashi; Brian E. Ellis

1992-01-01

55

On-line solid-phase extraction of ceramides from yeast with ceramide III imprinted monolith.  

PubMed

A molecularly imprinted polymeric monolith (MIPM) was prepared by in situ polymerization using styrene, glycidyl methacrylate and methacrylic acid as monomers, divinylbenzene and triallyl isocyanurate as cross-linking agents, and ceramide III as print molecule. The texture, pore size distribution, mobile phase flow characteristic, and chromatographic performance of the MIPM and a control monolith synthesized without the print molecule were examined, respectively. The results showed that using ceramide III as print molecule significantly affected the pore structure and pore distribution of the monolith, and greatly improved the retention of ceramide III and its analogues used in cosmetics as well. The retention of ceramide III on the MIPM could be reduced by increasing the ratio of chloroform to hexane in eluting buffer. The workability of the MIPM was firstly demonstrated through the separation of a model lipid mixture containing ceramide III and ergosterol, the main sterol impurity in yeast lipid extracts. The application of the ceramide III imprinted monolith to the isolation of ceramides from yeast lipid extracts was attempted and resulted in a considerable enrichment of ceramides, as shown by FIIR analysis. This indicates the potential of ceramide III imprinted monolith synthesized in the present study in the on-line solid-phase extraction of ceramides from yeast. PMID:12564688

Zhang, Minlian; Xie, Jianping; Zhou, Quan; Chen, Guoqiang; Li, Zheng

2003-01-17

56

Producao de Etanol por Fermentacao Extractiva com Celulas de Levedura Imobilizadas (Extractive Fermentation of Ethanol by Immobilized Yeast Cells).  

National Technical Information Service (NTIS)

Ethanol Production by Extractive Fermentation of glucose in the presence of media saturated with DBBP (dibutylbutylphosphorate) was performed in a semi-fluidized bed reactor by immobilized yeast cells of Saccharomyces bayanus in Ca-alginate matrices with ...

S. M. M. Dias

1991-01-01

57

Effects of yeast extract and glucose on xanthan production and cell growth in batch culture of Xanthomonas campestris  

Microsoft Academic Search

Although available kinetic data provide a useful insight into the effects of medium composition on xanthan production by\\u000a Xanthomonas campestris, they cannot account for the synergetic effects of carbon (glucose) and nitrogen (yeast extract) substrates on cell growth\\u000a and xanthan production. In this work, we studied the effects of the glucose\\/yeast-extract ratio (G\\/YE) in the medium on cell\\u000a growth and

Yang-Ming Lo; Shang-Tian Yang; David B. Min

1997-01-01

58

Analysis of the dynamics of relaxation type oscillation in glycolysis of yeast extracts.  

PubMed

In yeasts, the glycolysis may display oscillations of its metabolites while it is converting glucose. The dynamics of the oscillations has been investigated in cytoplasmic extracts of yeast under relaxation type conditions by determining the time course of some of the glycolytic metabolites. The compounds of the nucleotide pool have been identified as fast variables and the glucose derivatives as slow variables of the relaxation type. The period of oscillation has been subdivided into four phases which represent prominent parts of the limit cycle in the phase plane of a slow versus a fast variable. From the reaction processes in these phases, a dynamical picture of the mechanisms of oscillations is suggested. Accordingly, the oscillation results from an alternating activity of the fructose bisphosphate and the polysaccharide synthesis, both of which are coupled to glycolysis via the nucleotide pool. The processes in the phases are analyzed by calculating the rates of the reaction steps in the biochemical pathway. PMID:1832975

Das, J; Busse, H G

1991-08-01

59

Analysis of the dynamics of relaxation type oscillation in glycolysis of yeast extracts.  

PubMed Central

In yeasts, the glycolysis may display oscillations of its metabolites while it is converting glucose. The dynamics of the oscillations has been investigated in cytoplasmic extracts of yeast under relaxation type conditions by determining the time course of some of the glycolytic metabolites. The compounds of the nucleotide pool have been identified as fast variables and the glucose derivatives as slow variables of the relaxation type. The period of oscillation has been subdivided into four phases which represent prominent parts of the limit cycle in the phase plane of a slow versus a fast variable. From the reaction processes in these phases, a dynamical picture of the mechanisms of oscillations is suggested. Accordingly, the oscillation results from an alternating activity of the fructose bisphosphate and the polysaccharide synthesis, both of which are coupled to glycolysis via the nucleotide pool. The processes in the phases are analyzed by calculating the rates of the reaction steps in the biochemical pathway.

Das, J; Busse, H G

1991-01-01

60

A Yeast Metabolite Extraction Protocol Optimised for Time-Series Analyses  

PubMed Central

There is an increasing call for the absolute quantification of time-resolved metabolite data. However, a number of technical issues exist, such as metabolites being modified/degraded either chemically or enzymatically during the extraction process. Additionally, capillary electrophoresis mass spectrometry (CE-MS) is incompatible with high salt concentrations often used in extraction protocols. In microbial systems, metabolite yield is influenced by the extraction protocol used and the cell disruption rate. Here we present a method that rapidly quenches metabolism using dry-ice ethanol bath and methanol N-ethylmaleimide solution (thus stabilising thiols), disrupts cells efficiently using bead-beating and avoids artefacts created by live-cell pelleting. Rapid sample processing minimised metabolite leaching. Cell weight, number and size distribution was used to calculate metabolites to an attomol/cell level. We apply this method to samples obtained from the respiratory oscillation that occurs when yeast are grown continuously.

Sasidharan, Kalesh; Soga, Tomoyoshi; Tomita, Masaru; Murray, Douglas B.

2012-01-01

61

Sucrose fermentation by Saccharomyces cerevisiae lacking hexose transport.  

PubMed

Sucrose is the major carbon source used by Saccharomyces cerevisiae during production of baker's yeast, fuel ethanol and several distilled beverages. It is generally accepted that sucrose fermentation proceeds through extracellular hydrolysis of the sugar, mediated by the periplasmic invertase, producing glucose and fructose that are transported into the cells and metabolized. In the present work we analyzed the contribution to sucrose fermentation of a poorly characterized pathway of sucrose utilization by S. cerevisiae cells, the active transport of the sugar through the plasma membrane and its intracellular hydrolysis. A yeast strain that lacks the major hexose transporters (hxt1-hxt7 and gal2) is incapable of growing on or fermenting glucose or fructose. Our results show that this hxt-null strain is still able to ferment sucrose due to direct uptake of the sugar into the cells. Deletion of the AGT1 gene, which encodes a high-affinity sucrose-H(+) symporter, rendered cells incapable of sucrose fermentation. Since sucrose is not an inducer of the permease, expression of the AGT1 must be constitutive in order to allow growth of the hxt-null strain on sucrose. The molecular characterization of active sucrose transport and fermentation by S. cerevisiae cells opens new opportunities to optimize yeasts for sugarcane-based industrial processes. PMID:15741738

Batista, Anderson S; Miletti, Luiz C; Stambuk, Boris U

2004-01-01

62

Immunogenicity and protective efficacy of yeast extracts containing rotavirus-like particles: a potential veterinary vaccine.  

PubMed

Rotavirus is the most common cause of severe diarrhea in many animal species of economic interest. A simple, safe and cost-effective vaccine is required for the control and prevention of rotavirus in animals. In this study, we evaluated the use of Saccharomyces cerevisiae extracts containing rotavirus-like particles (RLP) as a vaccine candidate in an adult mice model. Two doses of 1mg of yeast extract containing rotavirus proteins (between 0.3 and 3 ?g) resulted in an immunological response capable of reducing the replication of rotavirus after infection. Viral shedding in all mice groups diminished in comparison with the control group when challenged with 100 50% diarrhea doses (DD50) of murine rotavirus strain EDIM. Interestingly, when immunizing intranasally protection against rotavirus infection was observed even when no increase in rotavirus-specific antibody titers was evident, suggesting that cellular responses were responsible of protection. Our results indicate that raw yeast extracts containing rotavirus proteins and RLP are a simple, cost-effective alternative for veterinary vaccines against rotavirus. PMID:24593996

Rodríguez-Limas, William A; Pastor, Ana Ruth; Esquivel-Soto, Ernesto; Esquivel-Guadarrama, Fernando; Ramírez, Octavio T; Palomares, Laura A

2014-05-19

63

Effect of sucrose in culture media on the location of glucosyltransferase of Streptococcus mutans and cell adherence to glass surfaces.  

PubMed Central

Streptococcus mutans strain B13 (serotype D) almost exclusively produced free glucosyltransferase (GTase) in the culture supernatant when grown in sucrose-free TTY broth medium, which was composed of Trypticase (Baltimore Biological Laboratory [BBL] Cockeysville, Md.), tryptose (Difco Laboratories, Detroit, Mich.), yeast extract (BBL), salts, and 1% glucose. Organisms grown in sucrose-free TTY broth retained very weak cell-associated GTase activity and did not adhere significantly to glass surfaces in the presence of exogenous sucrose. If sucrose was added to TTY broth, however, GTase was found on the cell surface where cell-bound, water-insoluble glucans were synthesized. Most commercially available products of Todd-Hewitt broth were found to contain trace amounts of sucrose, as did Trypticase soy broth (BBL), whereas brain heart infusion broth (Difco and BBL) was found to be essentially free of sucrose. Almost all detectable GTase activity was cell associated when S. mutans B13 was grown in Todd-Hewitt or trypticase soy broth. Heat-treated B13 cells grown in Todd-Hewitt broth and cell-free, water-insoluble glucans bound free GTase and produced marked adherence in the presence of sucrose. Experiments strongly suggest that the binding sites for free GTase are the surface glucans, and cell-associated and extracellular GTases are most likely alternate states of the same enzyme protein.

Hamada, S; Torii, M

1978-01-01

64

Buffered charcoal-yeast extract medium for the isolation of brucellae.  

PubMed

A patient with chronic osteomyelitis caused by Brucella abortus had negative agglutination titers. Because of a superimposed staphylococcal infection that resulted in the overgrowth of this organism on nonselective media, brucellae were isolated only on a selective buffered charcoal-yeast extract (BCYE) agar. Sixteen strains of various Brucella species were inoculated on BCYE agar; selective BCYE agar with polymyxin, anisomycin, and cefamandole; and brucella blood agar. The growth and recovery rates on the three media tested were comparable for 14 strains. BCYE agar with polymyxin, anisomycin, and cefamandole may be useful as a selective medium for the isolation of brucellae. PMID:2116452

Raad, I; Rand, K; Gaskins, D

1990-07-01

65

Optimized extract preparation methods and reaction conditions for improved yeast cell-free protein synthesis.  

PubMed

Cell-free protein synthesis (CFPS) has emerged as a powerful platform technology to help satisfy the growing demand for simple, affordable, and efficient protein production. In this article, we describe a novel CFPS platform derived from the popular bio-manufacturing organism Saccharomyces cerevisiae. By developing a streamlined crude extract preparation protocol and optimizing the CFPS reaction conditions we were able to achieve active firefly luciferase synthesis yields of 7.7?±?0.5?µg?mL(-1) with batch reactions lasting up to 2?h. This duration of synthesis is the longest ever reported for a yeast CFPS batch reaction. Furthermore, by removing extraneous processing steps and eliminating expensive reagents from the cell-free reaction, we have increased relative product yield (µg protein synthesized per $ reagent cost) over an alternative commonly used method up to 2000-fold from ?2?×?10(-4) to ?4?×?10(-1) ?µg?$(-1) , which now puts the yeast CPFS platform on par with other eukaryotic CFPS platforms commercially available. Our results set the stage for developing a yeast CFPS platform that provides for high-yielding and cost-effective expression of a variety of protein therapeutics and protein libraries. PMID:23832321

Hodgman, C Eric; Jewett, Michael C

2013-10-01

66

Effect of scenedesmus acuminatus green algae extracts on the development of Candida lipolytic yeast in gas condensate-containing media  

NASA Technical Reports Server (NTRS)

Data are given of a comparative study of the growth and development as well as the characteristics of the biomass of the C. Lipolytica yeast according to the content of raw protein, protein, lipids, vitamins in the B group, and residual hydrocarbons during growth in media with de-aromatized gas-condensate FNZ as the carbon source with aqueous and alcohol extracts of S. acuminatus as the biostimulants. It is shown that the decoction and aqueous extract of green algae has the most intensive stimulating effect on the yeast growth. When a decoction of algae is added to the medium, the content of residual hydrocarbons in the biomass of C. lipolytica yeast is reduced by 4%; the quantity of protein, lipids, thamine and inositol with replacement of the yeast autolysate by the decoction of algae is altered little.

Bilmes, B. I.; Kasymova, G. A.; Runov, V. I.; Karavayeva, N. N.

1980-01-01

67

Accessibility of DNA polymerases to repair synthesis during nucleotide excision repair in yeast cell-free extracts  

PubMed Central

Nucleotide excision repair (NER) removes a variety of DNA lesions. Using a yeast cell-free repair system, we have analyzed the repair synthesis step of NER. NER was proficient in yeast mutant cell-free extracts lacking DNA polymerases (Pol) ?, ? or ?. Base excision repair was also proficient without Pol?. Repair synthesis of NER was not affected by thermal inactivation of the temperature-sensitive mutant Pol? (pol1-17), but was reduced after thermal inactivation of the temperature-sensitive mutant Pol? (pol3-1) or Pol? (pol2-18). Residual repair synthesis was observed in pol3-1 and pol2-18 mutant extracts, suggesting a repair deficiency rather than a complete repair defect. Deficient NER in pol3-1 and pol2-18 mutant extracts was specifically complemented by purified yeast Pol? and Pol?, respectively. Deleting the polymerase catalytic domain of Pol? (pol2-16) also led to a deficient repair synthesis during NER, which was complemented by purified yeast Pol?, but not by purified yeast Pol?. These results suggest that efficient repair synthesis of yeast NER requires both Pol? and Pol? in vitro, and that the low fidelity Pol? is not accessible to repair synthesis during NER.

Wu, Xiaohua; Guo, Dongyu; Yuan, Fenghua; Wang, Zhigang

2001-01-01

68

In vitro antifungal activities of leaf extracts of Lippia alba (Verbenaceae) against clinically important yeast species.  

PubMed

Introduction There are few studies reporting the antifungal activities of Lippia alba extracts. Methods A broth microdilution assay was used to evaluate the antifungal effects of Lippia alba extracts against seven yeast species of Candida and Cryptococcus. The butanol fraction was investigated by gas chromatography-mass spectrometry. Results The butanol fraction showed the highest activity against Candida glabrata. The fraction also acted synergistically with itraconazole and fluconazole against C. glabrata. The dominant compounds in the butanol fraction were 2,2,5-trimethyl-3,4-hexanedione, 3,5-dimethyl-4-octanone and hexadecane. Conclusions The butanol fraction may be a good candidate in the search for new drugs from natural products with antifungal activity. PMID:24861304

Oliveira, Graziela Teixeira de; Ferreira, Jaqueline Maria Siqueira; Rosa, Luiz Henrique; Siqueira, Ezequias Pessoa de; Johann, Susana; Lima, Luciana Alves Rodrigues Dos Santos

2014-04-01

69

Contributions of sucrose synthase and invertase to the metabolism of sucrose in developing leaves: estimation by alternate substrate utilization  

SciTech Connect

The relative contributions of invertase and sucrose synthase to initial cleavage of phloem-imported sucrose was calculated for sink leaves of soybean (Glycine max L. Merr cv Wye) and sugar beet (Beta vulgaris L. monohybrid). Invertase from yeast hydrolyzed sucrose 4200 times faster than 1'-deoxy-1'-fluorosucrose (FS) while sucrose cleavage by sucrose synthase from developing soybean leaves proceeded only 3.6 times faster than cleavage of FS.(/sup 14/C)Sucrose and (/sup 14/C)FS, used as tracers of sucrose, were transported at identical rates to developing leaves through the phloem. The rate of label incorporation into insoluble products varied with leaf age from 3.4 to 8.0 times faster when (/sup 14/C)sucrose was supplied than when (/sup 14/C)FS was supplied. The discrimination in metabolism was related to enzymatic discriminations against FS to calculate the relative contributions of invertase and sucrose synthase to sucrose cleavage. In the youngest soybean leaves measured, 4% of final laminar length (FLL), all cleavage was by sucrose synthase. Invertase contribution to sucrose metabolism was 47% by 7.6% FLL, increased to 54% by 11% FLL, then declined to 42% for the remainder of the import phase. In sugar beet sink leaves at 30% FLL invertase contribution to sucrose metabolism was 58%.

Schmalstig, J.G.; Hitz, W.D.

1987-10-01

70

Biochemical characteristics of osmophilic yeasts isolated from pollens and honey.  

PubMed

A total of 1752 strains of osmophilic yeasts were isolated from honey and pollens. Forty-three strains of osmophilic yeasts produced polyols, among which 6 strains produced erythritol in good yields. On the other hand, 52 osmophilic yeasts converted sucrose to fructooligosaccharides, among which 8 strains produced both extra and intracellular beta-fructofuranosidase, which converted sucrose to fructooligosaccharides. This investigation concluded that osmophilic yeasts converted sucrose not only to polyols, but also to fructooligosaccharides in good yields. PMID:8987865

Park, Y K; Koo, M H; Oliveira, I M

1996-11-01

71

Engineering topology and kinetics of sucrose metabolism in Saccharomyces cerevisiae for improved ethanol yield  

Microsoft Academic Search

Sucrose is a major carbon source for industrial bioethanol production by Saccharomyces cerevisiae. In yeasts, two modes of sucrose metabolism occur: (i) extracellular hydrolysis by invertase, followed by uptake and metabolism of glucose and fructose, and (ii) uptake via sucrose-proton symport followed by intracellular hydrolysis and metabolism. Although alternative start codons in the SUC2 gene enable synthesis of extracellular and

Thiago O. Basso; Stefan de Kok; Marcelo Dario; Júlio Cézar A. do Espirito-Santo; Gabriela Müller; Paulo S. Schlölg; Carlos P. Silva; Aldo Tonso; Jean-Marc Daran; Andreas K. Gombert; Antonius J. A. van Maris; Jack T. Pronk; Boris U. Stambuk

2011-01-01

72

Clinical demonstration of isolation of Nocardia asteroides on buffered charcoal-yeast extract media.  

PubMed

Nocardia asteroides was isolated only from sputum samples, obtained from three patients with pulmonary nocardiosis, that had been cultured onto buffered charcoal-yeast extract (BCYE) and selective BCYE media as part of laboratory workups for Legionella species. A decontamination procedure with low-pH pretreatment (KCl-HCl solution) had been performed on the sputa prior to culture onto the BCYE media because direct cultures on the media were overgrown with commensal microflora. Chalky white colonies, 0.5 to 1.0 mm in diameter, that were subsequently identified as N. asteroides grew well on the BCYE media. Thus, the techniques and the selective media used for Legionella species were useful for isolating Nocardia species from sputum. PMID:1734058

Vickers, R M; Rihs, J D; Yu, V L

1992-01-01

73

Effect of yeast extract and vitamin B sub 12 on ethanol production from cellulose by Clostridium thermocellum I-1-B  

SciTech Connect

Addition to media of yeast extract, a vitamin mixture containing vitamin B{sub 12}, biotin, pyridoxamine, and p-aminobenzoic acid, or vitamin B{sub 12} alone enhanced formation of ethanol but decreased lactate production in the fermentation of cellulose by Clostridium thermocellum I-1-B. A similar effect was not observed with C. thermocellum ATCC 27405 and JW20.

Sato, Kanji; Goto, Shingo; Yonemura, Sotaro; Sekine, Kenji; Okuma, Emiko; Takagi, Yoshio; Honnami, Koyu; Saiki, Takashi (New Energy and Industrial Technology Development Organization, Chiba (Japan))

1992-02-01

74

Influence of yeast extract and casein hydrolysate on callus multiplication and somatic embryogenesis of date palm ( Phoenix dactylifera L.)  

Microsoft Academic Search

Complex organic additives are known to improve growth and differentiation of in vitro plant cultures. The present investigation was conducted to determine the effect of various concentrations of yeast extract (YE) and casein hydrolysate (CH) on callus growth and somatic embryogenesis in date palm cultivar Nabout Saif. Callus induced from shoot tip explants was grown on callus multiplication medium supplemented

Jameel M. Al-Khayri

2011-01-01

75

Accelerated solvent extraction of monacolin K from red yeast rice and purification by high-speed counter-current chromatography.  

PubMed

Monacolin K from red yeast rice was extracted by accelerated solvent extraction (ASE). The effects of various extraction parameters including extraction temperature, static extraction time and cycle index on yield were investigated using a DIONEX ASE 300 system to select the optimal conditions by an orthogonal test design L(9) (3)(3). The optimum extraction conditions were determined as follows: extraction temperature 120°C, static extraction time 7min, and cycle index 3. Under the optimal conditions, the yield of ASE extract and monacolin K was 5.35% and 9.26mg/g of dry red yeast rice, respectively. A separation and purification method of monacolin K was then established using high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (8:2:5:5, v/v/v/v). From 300mg of crude extract, 51.2mg of monacolin K was obtained with the purity of 98.7%. The chemical structure of isolated compound was identified by UV, ESI-MS and (1)H NMR. PMID:20869335

Liu, Yuqin; Guo, Xingfeng; Duan, Wenjuan; Wang, Xiao; Du, Jinhua

2010-10-15

76

In Vivo Hypocholesterolemic Effect of MARDI Fermented Red Yeast Rice Water Extract in High Cholesterol Diet Fed Mice  

PubMed Central

Fermented red yeast rice has been traditionally consumed as medication in Asian cuisine. This study aimed to determine the in vivo hypocholesterolemic and antioxidant effects of fermented red yeast rice water extract produced using Malaysian Agricultural Research and Development Institute (MARDI) Monascus purpureus strains in mice fed with high cholesterol diet. Absence of monacolin-k, lower level of ?-aminobutyric acid (GABA), higher content of total amino acids, and antioxidant activities were detected in MARDI fermented red yeast rice water extract (MFRYR). In vivo MFRYR treatment on hypercholesterolemic mice recorded similar lipid lowering effect as commercial red yeast rice extract (CRYR) as it helps to reduce the elevated serum liver enzyme and increased the antioxidant levels in liver. This effect was also associated with the upregulation of apolipoproteins-E and inhibition of Von Willebrand factor expression. In summary, MFRYR enriched in antioxidant and amino acid without monacolin-k showed similar hypocholesterolemic effect as CRYR that was rich in monacolin-k and GABA.

Beh, Boon Kee; Kong, Joan; Ho, Wan Yong; Mohd Yusof, Hamidah; Hussin, Aminuddin bin; Jaganath, Indu Bala; Alitheen, Noorjahan Banu; Jamaluddin, Anisah

2014-01-01

77

Glucosyltransferase production by Klebsiella sp. K18 and conversion of sucrose to palatinose using immobilized cells  

PubMed Central

The strain Klebsiella sp. K18 produces the enzyme glucosyltransferase and catalyses the conversion of sucrose to palatinose, an alternative sugar that presents low cariogenicity. Response Surface Methodology was successfully employed to determine the optimal concentration of culture medium components. Maximum glucosyltransferase production (21.78 U mL-1) was achieved using the optimized medium composed by sugar cane molasses (80 g L-1), bacteriological peptone (7 g L-1) and yeast extract (20 g L-1), after 8 hours of fermentation at 28°C. The conversion of sucrose to palatinose was studied utilizing immobilized cells in calcium alginate. The effects of the alginate concentration (2-4%), cell mass concentration (20-40%) and substrate concentration (25-45%) were evaluated and the yield of palatinose was approximately 62.5%.

Orsi, Daniela C.; Kawaguti, Haroldo Y.; Sato, Helia H.

2009-01-01

78

Rapid Extraction of Genomic DNA from Medically Important Yeasts and Filamentous Fungi by High-Speed Cell Disruption  

PubMed Central

Current methods of DNA extraction from different fungal pathogens are often time-consuming and require the use of toxic chemicals. DNA isolation from some fungal organisms is difficult due to cell walls or capsules that are not readily susceptible to lysis. We therefore investigated a new and rapid DNA isolation method using high-speed cell disruption (HSCD) incorporating chaotropic reagents and lysing matrices in comparison to standard phenol-chloroform (PC) extraction protocols for isolation of DNA from three medically important yeasts (Candida albicans, Cryptococcus neoformans, and Trichosporon beigelii) and two filamentous fungi (Aspergillus fumigatus and Fusarium solani). Additional extractions by HSCD were performed on Saccharomyces cerevisiae, Pseudallescheria boydii, and Rhizopus arrhizus. Two different inocula (108 and 107 CFU) were compared for optimization of obtained yields. The entire extraction procedure was performed on as many as 12 samples within 1 h compared to 6 h for PC extraction. In comparison to the PC procedure, HSCD DNA extraction demonstrated significantly greater yields for 108 CFU of C. albicans, T. beigelii, A. fumigatus, and F. solani (P ? 0.005), 107 CFU of C. neoformans (P ? 0.05), and 107 CFU of A. fumigatus (P ? 0.01). Yields were within the same range for 108 CFU of C. neoformans and 107 CFU of C. albicans for both HSCD extraction and PC extraction. For 107 CFU of T. beigelii, PC extraction resulted in a greater yield than did HSCD (P ? 0.05). Yields obtained from 108 and 107 CFU were significantly greater for filamentous fungi than for yeasts by the HSCD extraction procedure (P < 0.0001). By the PC extraction procedure, differences were not significant. For all eight organisms, the rapid extraction procedure resulted in good yield, integrity, and quality of DNA as demonstrated by restriction fragment length polymorphism, PCR, and random amplified polymorphic DNA. We conclude that mechanical disruption of fungal cells by HSCD is a safe, rapid, and efficient procedure for extracting genomic DNA from medically important yeasts and especially from filamentous fungi.

Muller, Frank-Michael C.; Werner, Katherine E.; Kasai, Miki; Francesconi, Andrea; Chanock, Stephen J.; Walsh, Thomas J.

1998-01-01

79

Silver toxicity to ferrous iron and pyrite oxidation and its alleviation by yeast extract in cultures of Thiobacillus ferrooxidans  

Microsoft Academic Search

Summary Ferrous-ion oxidation byThiobacillusferrooxidans was inhibited by 10-6 M Ag+ while a slight inhibition of growth was apparent with 10-7 M Ag+. The threshold toxic concentration was the seme for four different test strains. While prolonged lag phases resulted from culture exposure to Ag+, Fe2+ oxidation rates after the onset of growth showed little variation under these conditions. Yeast extract

Olli H. Tuovinen; Jaakko Puhakka; Paula Hiltunen; Katherine M. Dolan

1985-01-01

80

Evaluation of the yeast-extract signaling pathway leading to silymarin biosynthesis in milk thistle hairy root culture  

Microsoft Academic Search

The biosynthesis of silymarin, a potent antihepatotoxic compound, from the dried fruits of Silybum marianum L. Gaertn in hairy root cultures can be stimulated by a yeast extract elicitor. These results correlated with culture time,\\u000a and the biosynthesis reached a maximum of 0.47 mg g?1 DW by 72 h after culture (2-fold higher than the control). Lipoxygenase activity and linoleic acid content were

Tahereh Hasanloo; Roshanak Sepehrifar; Hassan Rahnama; Mohammad Reza Shams

2009-01-01

81

Semiconservative replication in yeast nuclear extracts requires Dna2 helicase and supercoiled template 1 1 Edited by M. Yaniv  

Microsoft Academic Search

We describe the preparation of nuclear extracts from yeast cells synchronised in S-phase that support the aphidicolin-sensitive, semi-conservative replication of primer-free, supercoiled plasmid in vitro. This is monitored by one and two-dimensional gel electrophoresis of replication intermediates that have incorporated [?-32P]dATP, by the conversion of methylated template DNA into a hemi-methylated or DpnI-resistant form, and by substitution of dTTP with

D Braguglia; P Heun; P Pasero; B. P Duncker; S. M Gasser

1998-01-01

82

Cell-Recycle Continuous Fermentation of Enterococcus faecalis RKY1 for Economical Production of Lactic Acid by Reduction of Yeast Extract Supplementation.  

PubMed

Both lactic acid productivity and cell growth were linearly correlated with yeast extract supplementation in batch fermentation. During conventional continuous operation, although fresh feed was introduced into the bioreactor with a significantly low dilution rate (0.04 h(-1)), the amount of yeast extract employed was not enough to maintain the growth of microorganism. However, when the fresh feed contained 100 g/l glucose and 2 g/l yeast extract during cellrecycle continuous operation at a dilution rate of 0.04 h(-1), more than 90 g/l lactic acid was continuously produced, with the average productivity of 3.72 g/l·h. In this experiment, 82 g of yeast extract (77% of reduction yield) could be reduced for the production of 1 kg of lactic acid compared with batch fermentation of a similar volumetric productivity. PMID:24561722

Lee, Ryun-Kyung; Ryu, Hwa-Won; Oh, Hurok; Kim, Mina; Wee, Young-Jung

2014-05-28

83

Measurement of the relative sweetness of stevia extract, aspartame and cyclamate\\/saccharin blend as compared to sucrose at different concentrations  

Microsoft Academic Search

Special diets are used to mitigate many human diseases. When these diets require changes in carbohydrate content, then sweetness becomes an important characteristic. The range of low-calorie sweeteners available to the food industry is expanding. It is essential to have an exact knowledge of the relative sweetness of various sweeteners in relation to different sucrose concentrations. The objective of this

H. M. A. B. Cardello; M. A. P. A. Da Silva; M. H. Damasio

1999-01-01

84

In VitroCulture of TrichogrammaSpp. on Artificial Diets Containing Yeast Extract and Ultracentrifuged Chicken Egg Yolk but Devoid of Insect Components  

Microsoft Academic Search

Trichogramma minutumRiley andTrichogramma brassicaeBezdenko (Hymenoptera: Trichogrammatidae) were culturedin vitrofrom eggs to adults on artificial diets, which contained no insect components. The diets contained ultracentrifuged chicken egg yolk, milk, Grace's insect medium, and yeast extract. The most important components were the yeast extract and ultracentrifuged chicken egg yolk. Addition of the sediment of ultracentrifuged chicken egg yolk to a diet containing

Zhong-Neng Xie; Zhi-Xin Wu; William C. Nettles; Guadalupe Saldaña; Donald A. Nordlund

1997-01-01

85

Yeast extract, brewer's yeast and spirulina in diets for Labeo rohita fingerlings affect haemato-immunological responses and survival following Aeromonas hydrophila challenge.  

PubMed

A feeding trial was conducted for 60 days to study the immunomodulatory role of three different immunostimulants yeast extract (YE), brewer's yeast (BY) and spirulina (SP) in Labeo rohita fingerlings. Four hundred and fifty fingerlings (avg. wt 3.35±0.15 g) were randomly distributed in ten treatments and fed with either of ten iso-nitrogenous and iso-caloric semi-purified diets, prepared with three incremental levels (1%, 2% and 4%) of different immunostimulants except the control. Growth parameters did not vary significantly (p>0.05) among the experimental groups. Haematology and serum parameters was performed before Aeromonas hydrophila challenge whereas respiratory burst activity was analysed following challenge. The respiratory burst activity, total leucocyte count, serum total protein and globulin was significantly higher (p<0.05) in YE 1% supplemented group. The survival (%) after challenging with A. hydrophila was also highest in the YE fed groups. The results indicate that among the different sources and levels of immunostimulants, YE at lower inclusion level is more effective in promoting the immune status of L. rohita fingerlings. PMID:20825959

Andrews, Simi Rose; Sahu, N P; Pal, A K; Mukherjee, S C; Kumar, Shivendra

2011-08-01

86

Evaluation of Extraction Protocols for Simultaneous Polar and Non-Polar Yeast Metabolite Analysis Using Multivariate Projection Methods  

PubMed Central

Metabolomic and lipidomic approaches aim to measure metabolites or lipids in the cell. Metabolite extraction is a key step in obtaining useful and reliable data for successful metabolite studies. Significant efforts have been made to identify the optimal extraction protocol for various platforms and biological systems, for both polar and non-polar metabolites. Here we report an approach utilizing chemoinformatics for systematic comparison of protocols to extract both from a single sample of the model yeast organism Saccharomyces cerevisiae. Three chloroform/methanol/water partitioning based extraction protocols found in literature were evaluated for their effectiveness at reproducibly extracting both polar and non-polar metabolites. Fatty acid methyl esters and methoxyamine/trimethylsilyl derivatized aqueous compounds were analyzed by gas chromatography mass spectrometry to evaluate non-polar or polar metabolite analysis. The comparative breadth and amount of recovered metabolites was evaluated using multivariate projection methods. This approach identified an optimal protocol consisting of 64 identified polar metabolites from 105 ion hits and 12 fatty acids recovered, and will potentially attenuate the error and variation associated with combining metabolite profiles from different samples for untargeted analysis with both polar and non-polar analytes. It also confirmed the value of using multivariate projection methods to compare established extraction protocols.

Tambellini, Nicolas P.; Zaremberg, Vanina; Turner, Raymond J.; Weljie, Aalim M.

2013-01-01

87

Simple method for the extraction and reversed-phase high-performance liquid chromatographic analysis of carotenoid pigments from red yeasts (Basidiomycota, Fungi)  

Microsoft Academic Search

A simple method for the extraction of carotenoid pigments from frozen wet cells of red yeasts (Basidiomycota) and their analysis by reversed-phase HPLC using a C18 column and a water\\/acetone solvent system is described. Typical red yeast carotenoids belonging to an oxidative series from the monocyclic ?-carotene to 2-hydroxytorularhodin and from the bicyclic ?-carotene to astaxanthin were separated. Pigment identity

Roland W. S. Weber; Heidrun Anke; Paolo Davoli

2007-01-01

88

Extractive biocatalysis: A powerful tool in selectivity control in yeast biotransformations  

Microsoft Academic Search

The effect of absorbing resins on the yeast reduction of ?,?-unsaturated carbonyl compounds is reported. Enantioselectivity, chemoselectivity and space-time yields of the biotransformation are impressively enhanced. The distribution of substrates and products between the resin and the water phase shows that the improved selectivity has to be attributed to the control of substrate concentration.The effect of absorbing resins on the

Paola D'Arrigo; Claudio Fuganti; Giuseppe Pedrocchi Fantoni; Stefano Servi

1998-01-01

89

Overcoming the toxicity effects of municipal wastewater sludge and biosolid extracts in the Yeast Estrogen Screen (YES) assay.  

PubMed

For nearly two decades, the Yeast Estrogen Screen (YES) has been used as a valuable tool for determining the total estrogenic potency of various environmental samples, including influent and effluent streams at municipal wastewater plants. However, applying the YES assay to wastewater sludges and stabilized biosolids has been problematic. This is due to co-extracted compounds from the solids either proving toxic to the yeast or masking the presence of estrogenic substances. The present research describes the development and validation of sample preparation steps that mitigate the toxicity effects of municipal wastewater sludge and biosolid samples in the YES assay, while allowing for reliable dose-dependent expression of estrogenic activity. A copper work-up for sulfur removal and chromatographic cleanup with silica and alumina were required in addition to solid-phase extraction to adequately remove interfering compounds. Sample stabilization methods such as autoclaving, lyophilization and formaldehyde treatment were found to be detrimental to the assay. Hence, heat-drying is recommended to prevent cytotoxicity and the degradation of estrogenic substances. PMID:22277884

Citulski, Joel; Farahbakhsh, Khosrow

2012-04-01

90

Iron Sucrose Injection  

MedlinePLUS

Iron sucrose injection comes as a solution (liquid) to inject intravenously (into a vein) by a doctor or nurse in a medical office or hospital outpatient clinic. It is usually injected over 2 ... number of doses based on your condition and how well you respond to the ...

91

Xylose fermentation by yeasts  

Microsoft Academic Search

Utilization and fermentation of xylose by the yeasts Pachysolen tannophilus I fGB 0101 and Pichia stipitis 5773 to 5776 under aerobic and anaerobic conditions are investigated. Pa. tannophilus requires biotin and thiamine for growth, whereas Pi. stipitis does not, and growth of both yeasts is stimulated by yeast extract. Pi. stipitis converts xylose (30 g\\/l) to ethanol under anaerobic conditions

H. Dellweg; M. Rizzi; H. Methner; D. Debus

1984-01-01

92

The sequential exposure to jasmonate, salicylic acid and yeast extract promotes sanguinarine accumulation in Argemone mexicana cell cultures.  

PubMed

The effects of the sequential application of methyl jasmonate (MeJa), salicylic acid (SA) and yeast extract (YE) to Argemone mexicana cell cultures were compared to either the sole application of each elicitor, or to the three-partite mixture. The highest sanguinarine accumulation occurred using the sequential treatment (ninefold over unexposed control cultures), followed by the single application of YE (fivefold). The elicitor mixture produced less sanguinarine than sole exposure to YE but higher than MeJa alone. SA did not produce any effect. Transcripts corresponding to tyrosine decarboxylase and berberine bridge enzyme accumulated in treated cells, but did not correlate with alkaloid accumulation. Discrete epifluorescence foci, surrounding the nucleus and scattered throughout the cytoplasm of elicited cells, suggested the presence of alkaloid-accumulating vesicles which could participate in a mechanism to avoid sanguinarine toxicity. PMID:22009570

Trujillo-Villanueva, Karen; Rubio-Piña, Jorge; Monforte-González, Miriam; Ramírez-Benítez, Efraín; Vázquez-Flota, Felipe

2012-02-01

93

Phloem Loading by the PmSUC2 Sucrose Carrier from Plantago major Occurs into Companion Cells.  

PubMed Central

High levels of mRNA for the sucrose-H+ symporter PmSUC2 have been found in the vascular bundles of petioles from Plantago major. The possible role of PmSUC2 in phloem loading was studied with antiserum raised against the recombinant PmSUC2 protein. This antiserum labeled a single 35-kD protein band in detergent extracts of P. major vascular bundles. It showed no cross-reaction with the P. major sucrose carrier PmSUC1, which was tested with detergent extracts from plasma membranes of transgenic yeast strains containing either the P. major sucrose transporter PmSUC1 or PmSUC2. The antiserum was used to determine the site of PmSUC2 expression in leaves, petioles, and roots of P. major. In cross-sections and longitudinal sections, the PmSUC2 protein was found in only one single cell type. These cells were identified as companion cells because they are nucleated, contain a dense cytoplasm, and are always adjacent to a sieve element. The labeled cells had the same longitudinal extension as did their sister sieve elements and always ended next to the sieve plates, which were characterized by specific staining. PmSUC2 mRNA and PmSUC2 protein were also detected in P. major roots. The function of PmSUC2 in the different organs and its role in phloem loading are discussed.

Stadler, R.; Brandner, J.; Schulz, A.; Gahrtz, M.; Sauer, N.

1995-01-01

94

Oligosaccharides Derived from Sucrose  

NASA Astrophysics Data System (ADS)

Sucrose is a non-reducing disaccharide, consisting of an ?-D-glucopyranosyl residue and a ?-D-fructofuranosyl residue linked covalently by their respective anomeric carbons (?-D-glucopyranosyl-1,2-?-D-fructofuranoside). It is not just a simple disaccharide, among others: in fact, the energy of its glycosidic bond is higher than that of a usual glycosidic bond. It is equal to 27.6 kJ/mol, which is similar to the energy of a nucleotide-sugar bond as in UDP-glucose or ADP-glucose. This means that sucrose is a protected and activated form of D-glucose (as well as of D-fructose), which plays a key role in the metabolism of plants, for a wide variety of synthesis reactions.

Monsan, Pierre F.; Ouarné, Francois

95

RNase Treatment of Yeast and Mammalian Cell Extracts Affects in Vitro Substrate Methylation by Type I Protein Arginine N-Methyltransferases  

Microsoft Academic Search

Type I protein arginine N-methyltransferases catalyze the formation of ?-NG-monomethylarginine and asymmetric ?-NG, NG-dimethylarginine residues using S-adenosyl-l-methionine as the methyl donor. In vitro these enzymes can modify a number of soluble methyl-accepting substrates in yeast and mammalian cell extracts including several species that interact with RNA. We treated normal and hypomethylated Saccharomyces cerevisiae and RAT1 cell extracts with RNase prior

Adam Frankel; Steven Clarke

1999-01-01

96

Vacuolar Acid hydrolysis as a physiological mechanism for sucrose breakdown.  

PubMed

Sucrose breakdown in mature acidic ;Persian' limes (Citrus aurantifolia [Christm.] Swing.) occurred at a rate of 30.6 picomoles per milliliter per day during 9 weeks storage at 15 degrees C. Neither enzyme of sucrose catabolism (sucrose synthase or acid/alkaline invertase) was present in extracts of mature storage tissue. The average vacuolar pH, estimated by direct measurement of sap from isolated vacuoles and by the methylamine method, was about 2.0 to 2.2. In vitro acid hydrolysis of sucrose at physiological concentrations in a buffered solution (pH 2.2) occurred at identical rates as in matured limes. The results indicate that sucrose breakdown in stored mature acidic limes occurs by acid hydrolysis. PMID:16666803

Echeverria, E; Burns, J K

1989-06-01

97

Engineering topology and kinetics of sucrose metabolism in Saccharomyces cerevisiae for improved ethanol yield.  

PubMed

Sucrose is a major carbon source for industrial bioethanol production by Saccharomyces cerevisiae. In yeasts, two modes of sucrose metabolism occur: (i) extracellular hydrolysis by invertase, followed by uptake and metabolism of glucose and fructose, and (ii) uptake via sucrose-proton symport followed by intracellular hydrolysis and metabolism. Although alternative start codons in the SUC2 gene enable synthesis of extracellular and intracellular invertase isoforms, sucrose hydrolysis in S. cerevisiae predominantly occurs extracellularly. In anaerobic cultures, intracellular hydrolysis theoretically enables a 9% higher ethanol yield than extracellular hydrolysis, due to energy costs of sucrose-proton symport. This prediction was tested by engineering the promoter and 5' coding sequences of SUC2, resulting in predominant (94%) cytosolic localization of invertase. In anaerobic sucrose-limited chemostats, this iSUC2-strain showed an only 4% increased ethanol yield and high residual sucrose concentrations indicated suboptimal sucrose-transport kinetics. To improve sucrose-uptake affinity, it was subjected to 90 generations of laboratory evolution in anaerobic, sucrose-limited chemostat cultivation, resulting in a 20-fold decrease of residual sucrose concentrations and a 10-fold increase of the sucrose-transport capacity. A single-cell isolate showed an 11% higher ethanol yield on sucrose in chemostat cultures than an isogenic SUC2 reference strain, while transcriptome analysis revealed elevated expression of AGT1, encoding a disaccharide-proton symporter, and other maltose-related genes. After deletion of both copies of the duplicated AGT1, growth characteristics reverted to that of the unevolved SUC2 and iSUC2 strains. This study demonstrates that engineering the topology of sucrose metabolism is an attractive strategy to improve ethanol yields in industrial processes. PMID:21963484

Basso, Thiago O; de Kok, Stefan; Dario, Marcelo; do Espirito-Santo, Júlio Cézar A; Müller, Gabriela; Schlölg, Paulo S; Silva, Carlos P; Tonso, Aldo; Daran, Jean-Marc; Gombert, Andreas K; van Maris, Antonius J A; Pronk, Jack T; Stambuk, Boris U

2011-11-01

98

Enhancing isomaltulose production by recombinant Escherichia coli producing sucrose isomerase: culture medium optimization containing agricultural wastes and cell immobilization.  

PubMed

Isomaltulose is a structural isomer of sucrose commercially used in food industries. In this work, recombinant Escherichia coli producing sucrose isomerase (SIase) was used to convert sucrose into isomaltulose. To develop an economical industrial medium, untreated cane molasses (10.63 g l?¹), yeast extract (25.93 g l?¹), and corn steep liquor (10.45 g l?¹) were used as main culture compositions for SIase production. The relatively high SIase activity (14.50 ± 0.11 U mg DCW?¹) was obtained by the recombinant cells. To the best of our knowledge, this is the first investigation on SIase production by engineered E. coli using untreated cane molasses. The recombinant E. coli cells expressing the SIase gene were immobilized in calcium alginate gel in order to improve the efficiency of recycling. The immobilization was most effective with 2 % (w/v) sodium alginate and 3 % (w/v) calcium chloride. The optimal initial biomass for immobilization was 20 % (w/v, wet wt.), with a hardening time of 8 h for cell immobilization. The immobilized E. coli cells exhibited good stability for 30 batches with the productivity of 0.45 g isomaltulose g pellet?¹ h?¹. A continuous isomaltulose formation process using a column reactor remained stable for 40 days with 83 ± 2 % isomaltulose yield, which would be beneficial for economical production of isomaltulose. PMID:23300051

Li, Sha; Xu, Hong; Yu, Jianguang; Wang, Yanyuan; Feng, Xiaohai; Ouyang, Pingkai

2013-10-01

99

Increased recovery of Legionella micdadei and Legionella bozemanii on buffered charcoal yeast extract agar supplemented with albumin.  

PubMed

The recovery of Legionella micdadei and L. bozemanii serogroups 1 and 2 from infected guinea pig spleens was evaluated by using two culture media: buffered charcoal yeast extract agar with 0.1% alpha-ketoglutarate (BCYE alpha) and the same medium supplemented with 1% bovine serum albumin (ABCYE alpha). At the lowest dilution of spleen tissue (10(-1)), recovery of all strains of L. micdadei and L. bozemanii was more efficient on ABCYE alpha than on BCYE alpha. L. micdadei strains had higher recovery rates on ABCYE alpha after another 10-fold dilution, but recoveries of L. bozemanii were similar on both media. Recovery rates for most test strains were comparable on BCYE alpha and ABCYE alpha at the highest dilution (10(-3)) of tissue tested. The presence of albumin in BCYE alpha increased the recovery rate of L. micdadei more than that of L. bozemanii. The use of ABCYE alpha medium in place of BCYE alpha may improve the recovery of L. micdadei and L. bozemanii from clinical specimens. Preliminary studies indicate that this medium also enhances recovery of certain Legionella spp. from environmental samples. PMID:2324282

Morrill, W E; Barbaree, J M; Fields, B S; Sanden, G N; Martin, W T

1990-03-01

100

The evaluation of mixtures of yeast and potato extracts in growth media for biomass production of lactic cultures.  

PubMed

The effectiveness of yeast extracts (YE) and potato extracts (PE) to promote growth of seven lactic cultures was evaluated by automated spectrophotometry (AS). Two aspects of the growth curve were analysed: (1) maximum biomass obtained (using ODmax) and (2) highest specific growth rate mu(max)) Eleven lots from the same PE-manufacturing process were examined for lot-to-lot variability. The ODmax values of three of the seven strains were significantly affected by lot source, but mu(max) was not significantly affected. The growth of bacteria was systematically lower in base medium containing 100% PE than in base medium containing 100% YE for both ODmax or mu(max) data, which could be related to the lower content in nitrogen-based compounds in PE. In AS assays, highest OD values for Lactobacillus casei EQ28, Lactobacillus rhamnosus R-011, Lactobacillus plantarum EQ12, and Streptococcus thermophilus R-083 were obtained with a mixture of PE and YE. Fermentations (2 L) were also carried out to determine the accuracy of AS to predict biomass levels obtained under fermentation trials. In these fermentations, replacement of 50% YE with PE was shown to enable good growth of S. thermophilus. With L. rhamnosus R-011, a high correlation (R2 = 0.95) was found between ODmax data obtained in the AS assays and that of the 2-L bioreactor when the same growth medium was used for both series of fermentations. However, AS was not as efficient when industrial media were used for the bioreactor assays. The relationship was still good for ODmax between AS data and that of the bioreactor data with L. rhamnosus R-011 in industrial LBS medium (R2 = 0.87), but was very poor with the S. thermophilus R-083 on Rosell #43 industrial medium (R2 = 0.33). Since PE cost 40% less than YE, there are strong economic advantages in considering such a partial replacement of YE by PE. PMID:12224561

Gaudreau, H; Renard, N; Champagne, C P; Van Horn, D

2002-07-01

101

Effects of yeast extract on the production and the quality of the exopolysaccharide, zooglan, produced by Z oogloea ramigera 115SLR  

Microsoft Academic Search

Although many studies have examined the influence of culture conditions on the production and composition of polysaccharides,\\u000a little is known about the factors influencing the quality of exopolysaccharides (EPS). In this work we studied the effect\\u000a of yeast extract on the production, composition and molecular weight of the EPS zooglan produced by Zoogloea ramigera 115SLR. This bacterium was grown on

S. Guillouet; J. H. Choi; C. K. Rha; A. J. Sinskey

1999-01-01

102

Anaerobic degradation of azo dye Drimaren blue HFRL in UASB reactor in the presence of yeast extract a source of carbon and redox mediator  

Microsoft Academic Search

This paper presents results on anaerobic degradation of the azo dye blue HFRL in a bench scale Upflow anaerobic sludge blanket\\u000a (UASB) reactor operated at ambient temperature. The results show that the addition of yeast extract (500 mg\\/L) increased color\\u000a removal (P < 0.05) from 62 to 93% despite the low chemical oxygen demand (COD) removal (~35%) which happened due to volatile fatty

B. E. L. Baêta; S. F. Aquino; S. Q. Silva; C. A. Rabelo

103

Optimizing Conditions for the Growth ofLactobacillus casei YIT 9018 in Tryptone-Yeast Extract-Glucose Medium by Using Response Surface Methodology  

Microsoft Academic Search

This study was undertaken to find optimum conditions of tryptone, yeast extract, glucose, Tween 80, and incubation temperature for the growth ofLactobacillus caseiYIT 9018 and to assess the effects of these factors by use of response surface methodology. A central composite design was used as an experimental design for allocation of treatment combinations. A second-order polynomial regression model, which was

SEJONG OH; SUNGSUE RHEEM; JAEHUN SIM; SANGKYO KIM; ANDYOUNGJIN BAEK

1995-01-01

104

Evolution of Plant Sucrose Uptake Transporters  

PubMed Central

In angiosperms, sucrose uptake transporters (SUTs) have important functions especially in vascular tissue. Here we explore the evolutionary origins of SUTs by analysis of angiosperm SUTs and homologous transporters in a vascular early land plant, Selaginella moellendorffii, and a non-vascular plant, the bryophyte Physcomitrella patens, the charophyte algae Chlorokybus atmosphyticus, several red algae and fission yeast, Schizosaccharomyces pombe. Plant SUTs cluster into three types by phylogenetic analysis. Previous studies using angiosperms had shown that types I and II are localized to the plasma membrane while type III SUTs are associated with vacuolar membrane. SUT homologs were not found in the chlorophyte algae Chlamydomonas reinhardtii and Volvox carterii. However, the characean algae Chlorokybus atmosphyticus contains a SUT homolog (CaSUT1) and phylogenetic analysis indicated that it is basal to all other streptophyte SUTs analyzed. SUTs are present in both red algae and S. pombe but they are less related to plant SUTs than CaSUT1. Both Selaginella and Physcomitrella encode type II and III SUTs suggesting that both plasma membrane and vacuolar sucrose transporter activities were present in early land plants. It is likely that SUT transporters are important for scavenging sucrose from the environment and intracellular compartments in charophyte and non-vascular plants. Type I SUTs were only found in eudicots and we conclude that they evolved from type III SUTs, possibly through loss of a vacuolar targeting sequence. Eudicots utilize type I SUTs for phloem (vascular tissue) loading while monocots use type II SUTs for phloem loading. We show that HvSUT1 from barley, a type II SUT, reverted the growth defect of the Arabidopsis atsuc2 (type I) mutant. This indicates that type I and II SUTs evolved similar (and interchangeable) phloem loading transporter capabilities independently.

Reinders, Anke; Sivitz, Alicia B.; Ward, John M.

2012-01-01

105

Combined extractives of red yeast rice, bitter gourd, chlorella, soy protein, and licorice improve total cholesterol, low-density lipoprotein cholesterol, and triglyceride in subjects with metabolic syndrome.  

PubMed

In this study, we aimed to examine the effects of a plant-extractive compound on lipid profiles in subjects with metabolic syndrome. We hypothesized that extractives from red yeast rice, bitter gourd, chlorella, soy protein, and licorice have synergistic benefits on cholesterol and metabolic syndrome. In this double-blinded study, adult subjects with metabolic syndrome were randomized to receive a plant-extractive compound or a placebo treatment for 12 weeks. Both total cholesterol (5.4 ± 0.8 to 4.4 ± 0.6 mmol/L, P < .001) and low-density lipoprotein cholesterol (3.4 ± 0.7 to 2.7 ± 0.5 mmol/L, P < .001) were significantly reduced after treatment with the plant extractives, and the magnitudes of reduction were significantly greater than in the placebo group (-1.0 ± 0.6 vs 0.0 ± 0.6mmol/L, P < .001; -0.7 ± 0.6 vs 0.0 ± 0.6 mmol/L, P < .001). The reduction in the fasting triglycerides level was significantly greater in the plant-extractive group than in the placebo group (-0.5 ± 0.8 vs -0.2 ± 1.0 mmol/L, P = .039). There was also a significantly greater reduction in the proportion of subjects with hypertensive criteria in the plant-extractive group than in the placebo group (P = .040). In conclusion, the plant extractives from red yeast rice, bitter gourd, chlorella, soy protein, and licorice were effective in reducing total and low-density lipoprotein cholesterol. The plant extractives also showed potential for reducing triglyceride and normalizing blood pressure. PMID:22348456

Lee, I-Te; Lee, Wen-Jane; Tsai, Ching-Min; Su, Ih-Jen; Yen, Hsien-Tung; Sheu, Wayne H-H

2012-02-01

106

Citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 and purification of citric acid.  

PubMed

In this study, citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 was investigated. After the compositions of the extract of Jerusalem artichoke tubers for citric acid production were optimized, the results showed that natural components of extract of Jerusalem artichoke tubers without addition of any other components were suitable for citric acid production by the yeast strain. During 10 L fermentation using the extract containing 84.3 g L(-1) total sugars, 68.3 g L(-1) citric acid was produced and the yield of citric acid was 0.91 g g(-1) within 336 h. At the end of the fermentation, 9.2 g L(-1) of residual total sugar and 2.1 g L(-1) of reducing sugar were left in the fermented medium. At the same time, citric acid in the supernatant of the culture was purified. It was found that 67.2 % of the citric acid in the supernatant of the culture was recovered and purity of citric acid in the crystal was 96 %. PMID:23584740

Wang, Ling-Fei; Wang, Zhi-Peng; Liu, Xiao-Yan; Chi, Zhen-Ming

2013-11-01

107

Cyclin B-cdk1 kinase stimulates ORC- and Cdc6-independent steps of semiconservative plasmid replication in yeast nuclear extracts.  

PubMed

Nuclear extracts from Saccharomyces cerevisiae cells synchronized in S phase support the semiconservative replication of supercoiled plasmids in vitro. We examined the dependence of this reaction on the prereplicative complex that assembles at yeast origins and on S-phase kinases that trigger initiation in vivo. We found that replication in nuclear extracts initiates independently of the origin recognition complex (ORC), Cdc6p, and an autonomously replicating sequence (ARS) consensus. Nonetheless, quantitative density gradient analysis showed that S- and M-phase nuclear extracts consistently promote semiconservative DNA replication more efficiently than G1-phase extracts. The observed semiconservative replication is compromised in S-phase nuclear extracts deficient for the Cdk1 kinase (Cdc28p) but not in extracts deficient for the Cdc7p kinase. In a cdc4-1 G1-phase extract, which accumulates high levels of the specific Clb-Cdk1 inhibitor p40(SIC1), very low levels of semiconservative DNA replication were detected. Recombinant Clb5-Cdc28 restores replication in a cdc28-4 S-phase extract yet fails to do so in the cdc4-1 G1-phase extract. In contrast, the addition of recombinant Xenopus CycB-Cdc2, which is not sensitive to inhibition by p40(SIC1), restores efficient replication to both extracts. Our results suggest that in addition to its well-characterized role in regulating the origin-specific prereplication complex, the Clb-Cdk1 complex modulates the efficiency of the replication machinery itself. PMID:9891057

Duncker, B P; Pasero, P; Braguglia, D; Heun, P; Weinreich, M; Gasser, S M

1999-02-01

108

Extraction and immobilization in one step of two ?-glucosidases released from a yeast strain of Debaryomyces hansenii  

Microsoft Academic Search

An extracellular, constitutive, and nonglucose repressed ?-glucosidase from a yeast strain of Debaryomyces hansenii was purified and immobilized using a one-step procedure on hydroxyapatite (HTP). Analysis of purified enzyme gave two bands both on SDS gel electrophoresis, native gel electrophoresis, and capillary electrophoresis. The two bands on SDS gels were positive for carbohydrate staining. Their apparent molecular mass was estimated

Paolo Riccio; Rocco Rossano; Mara Vinella; Paola Domizio; Francesco Zito; Francesco Sansevrino; Assunta D’Elia; Iolanda Rosi

1999-01-01

109

In vitro evaluation of the antimicrobial activity of eugenol, limonene, and citrus extract against bacteria and yeasts, representative of the spoiling microflora of fruit juices.  

PubMed

This article reports on the investigation on the bioactivity of eugenol, limonene, and citrus extract against three bacteria (Lactobacillus plantarum, Lactobacillus brevis, and Bacillus coagulans) and three yeasts (Saccharomyces bayanus, Pichia membranifaciens, and Rhodotorula bacarum), representing the spoilage microflora of fruit juices. The experiments were performed with laboratory media by using a microdilution method. Data were fitted using the Gompertz equation, and the kinetic parameters were used to evaluate the MIC and the dose-dependent effect (at suboptimal doses for each essential oil). Citrus extract was the most effective essential oil, and the results suggested the following susceptibility hierarchy, from the most sensitive microorganism to the most resistant one (values in parentheses represent MICs): S. bayanus (2 ppm) > R. bacarum (3 ppm) > P. membranifaciens (5 ppm) > B. coagulans (cells, 20 ppm) > L. brevis (40 ppm) > L. plantarum (>40 ppm). PMID:20501040

Bevilacqua, Antonio; Corbo, Maria Rosaria; Sinigaglia, Milena

2010-05-01

110

Sucrose Nephropathy Following IV Immunoglobulin.  

PubMed

Treatment with Intravenous Immunoglobulin (IVIg) has been found to be useful in patients with variety of diseases. IVIg infusions can produce allergic reactions. These adverse reactions are thought to be caused by activation of the complement cascade by the aggregation of IgG. To avoid this, a variety of stabilizing agents, including sucrose, are used. Sucrose is metabolized in the intestines by sucrase. If sucrose is given intravenously, this will be reabsorbed in to the proximal convoluted tubule and produce osmotic nephropathy which will present clinically as oliguric acute kidney injury. Patients with preexisting renal insufficiency, diabetes mellitus, elderly (>65 years), volume depletion and sepsis are more prone for these adverse effects and care should be taken not to use the IVIg with sucrose as a stabilizer in this population. If no other options are available, reductions in dose, concentration, and/or rate of administration of IVIg are warranted to reduce the incidence of renal failure. Pharmacist should be aware of the clinical scenario of the patient and choose the IVIg with appropriate stabilizer. PMID:24825978

Lakshmanadoss, Umashankar; Balakrishnan, Elangovan; DiSalle, Michael R

2010-03-01

111

Sucrose Nephropathy Following IV Immunoglobulin  

PubMed Central

Treatment with Intravenous Immunoglobulin (IVIg) has been found to be useful in patients with variety of diseases. IVIg infusions can produce allergic reactions. These adverse reactions are thought to be caused by activation of the complement cascade by the aggregation of IgG. To avoid this, a variety of stabilizing agents, including sucrose, are used. Sucrose is metabolized in the intestines by sucrase. If sucrose is given intravenously, this will be reabsorbed in to the proximal convoluted tubule and produce osmotic nephropathy which will present clinically as oliguric acute kidney injury. Patients with preexisting renal insufficiency, diabetes mellitus, elderly (>65 years), volume depletion and sepsis are more prone for these adverse effects and care should be taken not to use the IVIg with sucrose as a stabilizer in this population. If no other options are available, reductions in dose, concentration, and/or rate of administration of IVIg are warranted to reduce the incidence of renal failure. Pharmacist should be aware of the clinical scenario of the patient and choose the IVIg with appropriate stabilizer.

Lakshmanadoss, Umashankar; Balakrishnan, Elangovan; DiSalle, Michael R

2010-01-01

112

Use of high-ethanol-resistant yeast isolates from Nigerian palm wine in lager beer brewing  

Microsoft Academic Search

High-ethanol-resistant yeasts, characterized as Saccharomyces sp., were isolated from Nigerian palm wine with added sucrose for high gravity brewing. The yeast isolates that survived the highest ethanol production were used to ferment brewery wort and produced 8.2 to 8.5% (v\\/v) ethanol; values almost double that of the control yeast from a local brewery.

R. C. Agu; T. U. Anyanwu; A. H. Onwumelu

1993-01-01

113

Are sucrose transporter expression profiles linked with patterns of biomass partitioning in Sorghum phenotypes?  

PubMed Central

Sorghum bicolor is a genetically diverse C4 monocotyledonous species, encompassing varieties capable of producing high grain yields as well as sweet types which accumulate soluble sugars (predominantly sucrose) within their stems to high concentrations. Sucrose produced in leaves (sources) enters the phloem and is transported to regions of growth and storage (sinks). It is likely that sucrose transporter (SUT) proteins play pivotal roles in phloem loading and the delivery of sucrose to growth and storage sinks in all Sorghum ecotypes. Six SUTs are present in the published Sorghum genome, based on the BTx623 grain cultivar. Homologues of these SUTs were cloned and sequenced from the sweet cultivar Rio, and compared with the publically available genome information. SbSUT5 possessed nine amino acid sequence differences between the two varieties. Two of the remaining five SUTs exhibited single variations in their amino acid sequences (SbSUT1 and SbSUT2) whilst the rest shared identical sequences. Complementation of a mutant Saccharomyces yeast strain (SEY6210), unable to grow upon sucrose as the sole carbon source, demonstrated that the Sorghum SUTs were capable of transporting sucrose. SbSUT1, SbSUT4, and SbSUT6 were highly expressed in mature leaf tissues and hence may contribute to phloem loading. In contrast, SbSUT2 and SbSUT5 were expressed most strongly in sinks consistent with a possible role of facilitating sucrose import into stem storage pools and developing inflorescences.

Milne, Ricky J.; Byrt, Caitlin S.; Patrick, John W.; Grof, Christopher P. L.

2013-01-01

114

Sucrose Hydrolysis at Limited Water Concentration.  

National Technical Information Service (NTIS)

To enable development of a model describing reaction kinetics in dehydrated foods, sucrose hydrolysis was studied at limited water concentration. Saturated sucrose solutions containing various acids and inert solid materials gave identical rate constants ...

T. Schoebel S. R. Tannenbaum T. P. Labuza

1968-01-01

115

Effects of Sugar (Sucrose) on Children's Behavior.  

ERIC Educational Resources Information Center

Examined effects of sugar on behavior of 45 preschool and elementary school children. Provided all children with basic breakfast that included drink containing either 50 g of sucrose, a comparably sweet placebo, or very little sucrose. Found some small behavior changes in high-sucrose group. All effects were small in magnitude and not considered…

Rosen, Lee A.; And Others

1988-01-01

116

Cloning of sucrose:sucrose 1-fructosyltransferase from onion and synthesis of structurally defined fructan molecules from sucrose.  

PubMed

Sucrose (Suc):Suc 1-fructosyltransferase (1-SST) is the key enzyme in plant fructan biosynthesis, since it catalyzes de novo fructan synthesis from Suc. We have cloned 1-SST from onion (Allium cepa) by screening a cDNA library using acid invertase from tulip (Tulipa gesneriana) as a probe. Expression assays in tobacco (Nicotiana plumbaginifolia) protoplasts showed the formation of 1-kestose from Suc. In addition, an onion acid invertase clone was isolated from the same cDNA library. Protein extracts of tobacco protoplasts transformed with this clone showed extensive Suc-hydrolyzing activity. Conditions that induced fructan accumulation in onion leaves also induced 1-SST mRNA accumulation, whereas the acid invertase mRNA level decreased. Structurally different fructan molecules could be produced from Suc by a combined incubation of protein extract of protoplasts transformed with 1-SST and protein extract of protoplasts transformed with either the onion fructan:fructan 6G-fructosyltransferase or the barley Suc:fructan 6-fructosyltransferase. PMID:9701606

Vijn, I; van Dijken, A; Lüscher, M; Bos, A; Smeets, E; Weisbeek, P; Wiemken, A; Smeekens, S

1998-08-01

117

Characterization of Sucrolysis via the Uridine Diphosphate and Pyrophosphate-Dependent Sucrose Synthase Pathway 1  

PubMed Central

The breakdown of sucrose to feed both hexoses into glycolytic carbon flow can occur by the sucrose synthase pathway. This uridine diphosphate (UDP) and pyrophosphate (PPi)-dependent pathway was biochemically characterized using soluble extracts from several plants. The sucrolysis process required the simultaneous presence of sucrose, UDP, and PPi with their respective Km values being about 40 millimolar, 23 micromolar, and 29 micromolar. UDP was the only active nucleotide diphosphate. Slightly alkaline pH optima were observed for sucrose breakdown either to glucose 1-phosphate or to triose phosphate. Sucrolysis incrased with increasing temperature to near 50°C and then a sharp drop occurred between 55 and 60°C. The breakdown of sucrose to triose-P was activated by fructose 2,6-P2 which had a Km value near 0.2 micromolar. The cytoplasmic phosphofructokinase and fructokinase in plants were fairly nonselective for nucleotide triphosphates (NTP) but glucokinase definitely favored ATP. A predicted stoichiometric relationship of unity for UDP and PPi was measured when one also measured competing UDPase and pyrophosphatase activity. The cycling of uridylates, UDP to UTP to UDP, was demonstrated both with phosphofructokinase and with fructokinase. Enzyme activity measurements indicated that the sucrose synthase pathway has a major role in plant sucrose sink tissues. In the cytoplasmic sucrose synthase breakdown pathway, a role for the PPi-phosphofructokinase was to produce PPi while a role for the NTP-phosphofructokinase and for the fructokinase was to produce UDP.

Xu, Dian-Peng; Sung, Shi-Jean S.; Loboda, Tadeusz; Kormanik, Paul P.; Black, Clanton C.

1989-01-01

118

Characterization of sucrose-hydrolyzing enzymes of Zymomonas mobilis  

Microsoft Academic Search

Extracellular proteins of Zymomonas mobilis were analyzed by two-dimensional gel electrophoresis and protein maps drawn up. One of these proteins showed sucrose-hydrolyzing activity, as indicated by activity staining after polyacrylamide gel electrophoresis. It was purified from the extracellular extract of a glucose fermentation by polyacrylamide gel electrophoresis, using a two-step procedure. The molecular mass of the protein was 46 kDa

Laurence Preziosi; Gérard P. F. Michel; Jacques Baratti

1990-01-01

119

Sucrose transport into stalk tissue of sugarcane  

SciTech Connect

The productivity of higher plants is, in part, dependent on transport of photosynthate from source to sink (in sugarcane, stalk) and upon its assimilation in cells of the sink tissue. In sugarcane, sucrose has been reported to undergo hydrolysis in the apoplast before uptake into the storage parenchyma, whereas recently, sucrose was reported to be taken up intact. This work was based on lack of randomization of ({sup 14}C)fructosyl sucrose accumulated after feeding tissue slices with this sugar. In this report, we present evidence from slices of stalk tissue that sucrose is taken up intact via a carrier-mediated, energy-dependent process. The evidence includes: (1) uptake of fluorosucrose, an analog of sucrose not subject to hydrolysis by invertase; (2) little or no randomization of ({sup 14}C) fructosyl sucrose taken up; (3) the presence of a saturable as well as a linear component of sucrose uptake; and (4) inhibition of both the saturable and linear components of sucrose uptake by protonophore and sulhydryl agents. Hexoses can also be taken up, and at a greater efficiency than sucrose. It is probable that both hexose and sucrose can be transported across the plasma membrane, depending on the physiological status of the plant.

Thom, M.; Maretzki, A. (Hawaiian Sugar Planters' Association, Aiea, HI (USA))

1990-05-01

120

Molecular Control of Sucrose Utilization in Escherichia coli W, an Efficient Sucrose-Utilizing Strain  

PubMed Central

Sucrose is an industrially important carbon source for microbial fermentation. Sucrose utilization in Escherichia coli, however, is poorly understood, and most industrial strains cannot utilize sucrose. The roles of the chromosomally encoded sucrose catabolism (csc) genes in E. coli W were examined by knockout and overexpression experiments. At low sucrose concentrations, the csc genes are repressed and cells cannot grow. Removal of either the repressor protein (cscR) or the fructokinase (cscK) gene facilitated derepression. Furthermore, combinatorial knockout of cscR and cscK conferred an improved growth rate on low sucrose. The invertase (cscA) and sucrose transporter (cscB) genes are essential for sucrose catabolism in E. coli W, demonstrating that no other genes can provide sucrose transport or inversion activities. However, cscK is not essential for sucrose utilization. Fructose is excreted into the medium by the cscK-knockout strain in the presence of high sucrose, whereas at low sucrose (when carbon availability is limiting), fructose is utilized by the cell. Overexpression of cscA, cscAK, or cscAB could complement the W?cscRKAB knockout mutant or confer growth on a K-12 strain which could not naturally utilize sucrose. However, phenotypic stability and relatively good growth rates were observed in the K-12 strain only when overexpressing cscAB, and full growth rate complementation in W?cscRKAB also required cscAB. Our understanding of sucrose utilization can be used to improve E. coli W and engineer sucrose utilization in strains which do not naturally utilize sucrose, allowing substitution of sucrose for other, less desirable carbon sources in industrial fermentations.

Sabri, Suriana; Nielsen, Lars K.

2013-01-01

121

Influence of autochthonous lactic acid bacteria and enzymatic yeast extracts on the microbiological, biochemical and sensorial properties of Lben generic products.  

PubMed

In this study we identified Lactococcus lactis subsp. lactis, Lc. lactis subsp. lactis biovar diacetylactis, Kluyveromices lactis and Saccharomyces cerevisiae as the dominant microorganisms of traditional Moroccan acid-alcoholic fermented milk named Lben. The low pH (3·8±0·3), lactose (16·8±3·4 mg/l) and lactic acid (8·16±0·6 mg/l) content indicated that a strong fermentation occurred in the traditional product which was also characterised by the substantial presence of ethanol and typical volatile carbonyl compounds (i.e., acetoin, diacetyl and acetaldehyde). Microbiological analyses of experimental Lben manufactured with selected strains (isolated from the traditional product) of Lc. lactis subsp. lactis and Lc. lactis subsp. lactis biovar. diacetylactis alone (batch A) and in combination with enzymatic extract of a K. lactis strain (batch B) indicated a good effectiveness of the starters employed (?1010 CFU/g of lactococci after 8 h of incubation) and a significant effect of the yeast enzyme extract on lactococci viability. Despite slight changes in the physicochemical characteristics of the two Lben during the 15 d storage period, volatile compounds (i.e. ethanol, acetaldehyde, diacetyl and acetoin) were consistently higher in batch B. Moreover, sensorial analysis performed after 15 d of storage, highlighted higher odour and flavour intensity, vegetable odour and viscosity in batch B while batch A displayed higher astringency. PMID:24642233

Mangia, Nicoletta P; Garau, Giovanni; Murgia, Marco A; Bennani, Abdelmajid; Deiana, Pietrino

2014-05-01

122

Mutations in the membrane anchor of yeast cytochrome c1 compensate for the absence of Oxa1p and generate carbonate-extractable forms of cytochrome c1.  

PubMed Central

Oxa1p is a mitochondrial inner membrane protein that is mainly required for the insertion/assembly of complex IV and ATP synthase and is functionally conserved in yeasts, humans, and plants. We have isolated several independent suppressors that compensate for the absence of Oxa1p. Molecular cloning and sequencing reveal that the suppressor mutations (CYT1-1 to -6) correspond to amino acid substitutions that are all located in the membrane anchor of cytochrome c1 and decrease the hydrophobicity of this anchor. Cytochrome c1 is a catalytic subunit of complex III, but the CYT1-1 mutation does not seem to affect the electron transfer activity. The double-mutant cyt1-1,164, which has a drastically reduced electron transfer activity, still retains the suppressor activity. Altogether, these results suggest that the suppressor function of cytochrome c1 is independent of its electron transfer activity. In addition to the membrane-bound cytochrome c1, carbonate-extractable forms accumulate in all the suppressor strains. We propose that these carbonate-extractable forms of cytochrome c1 are responsible for the suppressor function by preventing the degradation of the respiratory complex subunits that occur in the absence of Oxa1p.

Hamel, P; Lemaire, C; Bonnefoy, N; Brivet-Chevillotte, P; Dujardin, G

1998-01-01

123

Dielectric properties of honey adulterated with sucrose syrup  

Microsoft Academic Search

Sucrose syrup is a common additive in honey adulteration. To provide information for developing a cheap, simple, convenient and rapid sucrose–adulterated honey detector or sucrose content sensor, the permittivities of pure jujube, yellow-locust and milk-vetch flower honey, pure sucrose syrup and honey–sucrose syrup mixtures with sucrose content from 0% (pure honey) to 80% (pure sucrose syrup) were studied from 10

Wenchuan Guo; Yi Liu; Xinhua Zhu; Shaojin Wang

2011-01-01

124

The absorption of protons with alpha-methyl glucoside and alpha-thioethyl glucoside by the yeast N.C.Y.C. 240. Evidence against the phosphorylation hypothesis.  

PubMed Central

1. When yeast N.C.Y.C. 240 was grown with maltose in a complex medium based on yeast extract and peptone, washed cell preparations fermented alpha-methyl glucoside much more slowly than maltose. 2. The yeast absorbed alpha-methyl[14C]glucoside from a 10mM solution in the presence of antimycin and iodoacetamide, producing [14C]glucose, which accumulated outside the cells. The yeast itself contained hexose phosphates, trehalose, alpha-methyl glucoside and other products labelled with 14C, but no alpha-methyl glucoside phosphate. 3. About 1 equiv. of protons was absorbed with each equivalent of alpha-methylglucoside, and 1 equiv. of K+ ions left the yeast. 4. alpha-Thioethyl glucoside was also absorbed along with protons. Studies by g.l.c. showed that the yeast concentrated the compound without metabolizing it. 5. The presence of trehalose, sucrose, maltose, L-sorbose, glucose or alpha-phenyl glucoside in each case immediately stimulated proton uptake, whereas fructose, 3-O-methylglucose and 2-deoxyglucose failed to do so. 6. The observations support the conclusion that alpha-thioethyl glucoside, alpha-methyl glucoside and maltose are substrates of one or more proton symports, whereas they seem inconsistent with the notion that the absorption of alpha-methyl glucoside involves the phosphorylation of the carbohydrate [Van Stevenick (1970) Biochim. Biophys. Acta 203, 376-384].

Brocklehurst, R; Gardner, D; Eddy, A A

1977-01-01

125

Antisense repression of sucrose synthase in carrot (Daucus carota L.) affects growth rather than sucrose partitioning  

Microsoft Academic Search

To unravel the roles of sucrose synthase in carrot, we reduced its activity in transgenic carrot plants by an antisense approach. For this purpose, the cDNA for the main form of carrot sucrose synthase was expressed in antisense orientation behind the 35S promoter of cauliflower mosaic virus. In independent antisense plant lines grown in soil, sucrose synthase activity was reduced

Guo-Qing Tang; Arnd Sturm

1999-01-01

126

Sucrose accumulation in mature sweet melon fruits. [Cucumis melo  

SciTech Connect

Mesocarp tissue from sucrose-accumulating sweet melon (Cucumis melo cv. Galia) showed sucrose synthase activity (ca 1 nkat/gfw) while soluble acid invertase and sucrose phosphate synthase activities were not observed. Sucrose uptake into mesocarp discs was linear with sucrose concentration (1-500 mM) and unaffected by PCMBS and CCCP. Sucrose compartmentation into the vacuole also increased linearly with sucrose concentration as indicated by compartmental efflux kinetics. Mesocarp discs incubated in /sup 14/C-fructose + UDP-glu synthesized /sup 14/C-sucrose and efflux kinetics indicated that the /sup 14/C-sucrose was compartmentalized. These data support the hypothesis that two mechanisms are involved in sucrose accumulation in sweet melon: (1) compartmentation of intact sucrose and (2) synthesis of sucrose via sucrose synthase and subsequent compartmentation in the vacuole.

Schaffer, A.A.; Aloni, B.

1987-04-01

127

Sugarcane genes associated with sucrose content  

PubMed Central

Background - Sucrose content is a highly desirable trait in sugarcane as the worldwide demand for cost-effective biofuels surges. Sugarcane cultivars differ in their capacity to accumulate sucrose and breeding programs routinely perform crosses to identify genotypes able to produce more sucrose. Sucrose content in the mature internodes reach around 20% of the culms dry weight. Genotypes in the populations reflect their genetic program and may display contrasting growth, development, and physiology, all of which affect carbohydrate metabolism. Few studies have profiled gene expression related to sugarcane's sugar content. The identification of signal transduction components and transcription factors that might regulate sugar accumulation is highly desirable if we are to improve this characteristic of sugarcane plants. Results - We have evaluated thirty genotypes that have different Brix (sugar) levels and identified genes differentially expressed in internodes using cDNA microarrays. These genes were compared to existing gene expression data for sugarcane plants subjected to diverse stress and hormone treatments. The comparisons revealed a strong overlap between the drought and sucrose-content datasets and a limited overlap with ABA signaling. Genes associated with sucrose content were extensively validated by qRT-PCR, which highlighted several protein kinases and transcription factors that are likely to be regulators of sucrose accumulation. The data also indicate that aquaporins, as well as lignin biosynthesis and cell wall metabolism genes, are strongly related to sucrose accumulation. Moreover, sucrose-associated genes were shown to be directly responsive to short term sucrose stimuli, confirming their role in sugar-related pathways. Conclusion - Gene expression analysis of sugarcane populations contrasting for sucrose content indicated a possible overlap with drought and cell wall metabolism processes and suggested signaling and transcriptional regulators to be used as molecular markers in breeding programs. Transgenic research is necessary to further clarify the role of the genes and define targets useful for sugarcane improvement programs based on transgenic plants.

Papini-Terzi, Flavia S; Rocha, Flavia R; Vencio, Ricardo ZN; Felix, Juliana M; Branco, Diana S; Waclawovsky, Alessandro J; Del Bem, Luiz EV; Lembke, Carolina G; Costa, Maximiller DL; Nishiyama, Milton Y; Vicentini, Renato; Vincentz, Michel GA; Ulian, Eugenio C; Menossi, Marcelo; Souza, Glaucia M

2009-01-01

128

Kinetics of immobilized sucrose phosphorylase  

SciTech Connect

Sucrose phosphorylase was immobilized on porous ceramic beads with 3-aminopropyltrie-thoxysilane and glutaraldehyde. It was determined experimentally that under laboratory conditions there was no diffusional resistance to the enzyme-catalyzed reaction. The half-life of the immobilized enzyme varied from about 35 days at 30 degrees C to about 5 days at 40 degrees C. The pH optimum was found to be between 6.5 and 7.0. The activation energy for the reaction was found to be about 12.5 kcal/mol. Eleven independent kinetic constants in the complete rate equation for the previously proposed ping-pong mechanism were found to be in good agreement with those for the soluble enzyme. (Refs. 19).

Taylor, F.; Cheng Shung Gong, L.C.; Tsao, G.T.

1982-02-01

129

"Sucrose analgesia": absorptive mechanism or taste perception?  

PubMed

It remains unclear whether "sucrose analgesia" is related to a pre- or postabsorptive mechanism. In a double blind cross over study sucrose reduced the pain response of preterm infants exposed to heel prick blood samples only when it was administered into the mouth. It was ineffective when administered intragastrically. PMID:10325795

Ramenghi, L A; Evans, D J; Levene, M I

1999-03-01

130

Comparison of the sequestering properties of yeast cell wall extract and hydrated sodium calcium aluminosilicate in three in vitro models accounting for the animal physiological bioavailability of zearalenone.  

PubMed

The sequestration/inactivation of the oestrogenic mycotoxin zearalenone (ZEA) by two adsorbents--yeast cell wall extract (YCW) and hydrated sodium calcium aluminosilicate (HSCAS)--was studied in three laboratory models: (1) an in vitro model was adapted from referenced methods to test for the sequestrant sorption capabilities under buffer conditions at two pH values using liquid chromatography coupled to a fluorescence detector for toxin quantification; (2) a second in vitro model was used to evaluate the sequestrant sorption stability according to pH variations and using ³H-labelled ZEA at low toxin concentration; and (3) an original, ex vivo Ussing chamber model was developed to further understand the transfer of ZEA through intestinal tissue and the impact of each sequestrant on the mycotoxin bioavailability of ³H-labelled ZEA. YCW was a more efficient ZEA adsorbent than HSCAS in all three models, except under very acidic conditions (pH 2.5 or 3.0). The Ussing chamber model offered a novel, ex vivo, alternative method for understanding the effect of sequestrant on the bioavailability of ZEA. The results showed that compared with HSCAS, YCW was more efficient in sequestering ZEA and that it reduced the accumulation of ZEA in the intestinal tissue by 40% (p < 0.001). PMID:23844575

Yiannikouris, A; Kettunen, H; Apajalahti, J; Pennala, E; Moran, C A

2013-01-01

131

Comparison of a novel MPN method against the yeast extract agar (YEA) pour plate method for the enumeration of heterotrophic bacteria from drinking water.  

PubMed

This study compared the Quanti-Disc most probable number (MPN) test for heterotrophic bacteria from drinking water with the widely used yeast extract agar (YEA) pour plate method. The Quanti-Disc test module contains 50 reaction wells in which a medium has been pre-deposited. The medium contains a suite of three fluorogenic enzyme substrates selected for the detection of enzymes expressed widely by heterotrophic bacteria. The MPN of heterotrophic bacteria is calculated from the number of fluorescing reaction wells after incubation of a sample. Quanti-Disc and the YEA pour plate method were compared according to guidance on comparing methods given in United Kingdom national guidance and ISO 17994:2004. The two methods were also challenged with reference strains and isolates of heterotrophic bacteria from drinking water. This indicated that heterotrophic bacteria commonly encountered in drinking water are detected by both the YEA pour plate method and Quanti-Disc. Analysis of data from split water samples (723 for 37 degrees C tests and 872 for 22 degrees C tests) from nine geographically diverse laboratories in England and Wales demonstrated that the Quanti-Disc method is equivalent to the YEA pour plate method for the analysis of heterotrophic bacteria from drinking and similar waters at 37 degrees C, and superior to YEA for the analysis at 22 degrees C. The Quanti-Disc method is a simple and efficient alternative method for the enumeration of heterotrophic bacteria from drinking water. PMID:18534656

Sartory, David P; Gu, Haoyi; Chen, Chun-Ming

2008-07-01

132

21 CFR 172.833 - Sucrose acetate isobutyrate (SAIB).  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Sucrose acetate isobutyrate (SAIB). 172.833...CONSUMPTION Multipurpose Additives § 172.833 Sucrose acetate isobutyrate (SAIB). Sucrose acetate isobutyrate may be safely used in...

2009-04-01

133

21 CFR 172.833 - Sucrose acetate isobutyrate (SAIB).  

Code of Federal Regulations, 2010 CFR

...3 2010-01-01 2009-04-01 true Sucrose acetate isobutyrate (SAIB). 172.833...CONSUMPTION Multipurpose Additives § 172.833 Sucrose acetate isobutyrate (SAIB). Sucrose acetate isobutyrate may be safely used in...

2010-01-01

134

Sucrose regulates elongation of carrot somatic embryo radicles as a signal molecule.  

PubMed

Elongation of carrot somatic embryo radicles was inhibited by sucrose at or above 5% (145 mM). This effect would not be released until the sucrose concentration was lowered again. Morphological and cytological studies as well as determination of ABA content and analysis of the expression mode of a Lea gene, all point to its similarity to natural dormancy and germination of seeds. Use of monosaccharides (glucose and fructose), other disaccharide (maltose), and isomolar concentration of osmotica (mannitol and sorbitol), did not show similar regulatory effect. It is thus clear that the regulatory effect is not a result of simple osmotic stress. Hexokinase inhibitors such as glucosamine and N -acetyl-glucosamine did not exert any influence on the regulation-deregulation effects of sucrose. Mannose, which inhibits germination of Arabidopsis seeds, did not prevent carrot somatic embryo radicles from elongating. It is thus inferred that this sucrose-signaling pathway may be independent of hexokinase. As a first step to understand the molecular mechanism of this process, a carrot sucrose transporter gene ( cSUT ) expressed in the embryos and roots specifically was isolated. Studies on transformed yeast mutant with cSUT cDNA identified its sucrose transport activity. Northern hybridization and gel retardation experiment revealed that there is a marked increase in expression of cSUT at the beginning of somatic embryo germination, and this is attributed to regulation on the level of transcription. This suggested the possibility that cSUT has an important role in this sucrose signal regulation system. PMID:15284498

Yang, Zhipan; Zhang, Lei; Diao, Fengqiu; Huang, Meijuan; Wu, Naihu

2004-02-01

135

Kinetics analysis of growth and lactic acid production in pH-controlled batch cultures of Lactobacillus casei KH-1 using yeast extract\\/corn steep liquor\\/glucose medium  

Microsoft Academic Search

This study was performed to determine the optimal conditions of yeast extract, corn steep liquor and glucose concentration for the growth and lactic acid production of Lactobacillus casei KH-1 and to assess the effect of these conditions using a response surface methodology. A Box-Behnken design was used as an experimental design for the allocation of treatment combination as 17 pH-controlled

Mi-Young Ha; Si-Wouk Kim; Yong-Woon Lee; Myong-Jun Kim; Seong-Jun Kim

2003-01-01

136

Functional Analysis of Arabidopsis Sucrose Transporters  

SciTech Connect

Sucrose is the main photosynthetic product that is transported in the vasculature of plants. The long-distance transport of carbohydrates is required to support the growth and development of net-importing (sink) tissues such as fruit, seeds and roots. This project is focused on understanding the transport mechanism sucrose transporters (SUTs). These are proton-coupled sucrose uptake transporters (membrane proteins) that are required for transport of sucrose in the vasculature and uptake into sink tissues. The accomplishments of this project included: 1) the first analysis of substrate specificity for any SUT. This was accomplished using electrophysiology to analyze AtSUC2, a sucrose transporter from companion cells in Arabidopsis. 2) the first analysis of the transport activity for a monocot SUT. The transport kinetics and substrate specificity of HvSUT1 from barley were studied. 3) the first analysis of a sucrose transporter from sugarcane. and 4) the first analysis of transport activity of a sugar alcohol transporter homolog from plants, AtPLT5. During this period four primary research papers, funded directly by the project, were published in refereed journals. The characterization of several sucrose transporters was essential for the current effort in the analysis of structure/function for this gene family. In particular, the demonstration of strong differences in substrate specificity between type I and II SUTs was important to identify targets for site-directed mutagenesis.

John M. Ward

2009-03-31

137

Enzymatic conversion of sucrose to hydrogen  

SciTech Connect

The enzymatic conversion of sugars to hydrogen could be a promising method for alternative fuel production. Maple tree sap is a source of environmental sugar (e.g., sucrose) that has the potential to be converted into hydrogen using the enzymes invertase, glucose dehydrogenase (GDH), hydrogenase, and glucose isomerase (GI) and the cofactor NADP{sup +}/NADPH. The kinetics of hydrogen production have been studied, and optimal conditions for hydrogen production are described. At low initial sucrose concentrations, in the absence of glucose isomerase, stoichiometric yields of mol of H{sub 2}/mol of sucrose were achieved. At higher sucrose concentrations, the yield of hydrogen declined so that at an initial sucrose concentration of 292 mM only 7% yield of hydrogen was obtained. The reason for this low yield was studied and shown not to be caused by enzyme inactivation or a pH drop during the reaction but due to an instability of the cofactor NADP{sup +}. Although gluconic and inhibited both NADPH production and oxidation of GDH and hydrogenase, respectively, it was not the major cause of NADP{sup +} instability. Fructose was also shown to be converted to hydrogen if GI was present in the reaction mixture. Also, by starting with sucrose, 1.34 mol of H{sub 2}/mol of sucrose was obtained if GI was present in the reaction mixture.

Woodward, J.; Orr, M. [Oak Ridge National Lab., TN (United States). Chemical Technology Div.] [Oak Ridge National Lab., TN (United States). Chemical Technology Div.

1998-11-01

138

Enzymatic conversion of sucrose to hydrogen  

PubMed

The enzymatic conversion of sugars to hydrogen could be a promising method for alternative fuel production. Maple tree sap is a source of environmental sugar (e.g., sucrose) that has the potential to be converted into hydrogen using the enzymes invertase, glucose dehydrogenase (GDH), hydrogenase, and glucose isomerase (GI) and the cofactor NADP+/NADPH. The kinetics of hydrogen production have been studied, and optimal conditions for hydrogen production are described. At low initial sucrose concentrations, in the absence of glucose isomerase, stoichiometric yields of 1 mol of H2/mol of sucrose were achieved. At higher sucrose concentrations, the yield of hydrogen declined so that at an initial sucrose concentration of 292 mM only 7% yield of hydrogen was obtained. The reason for this low yield was studied and shown not to be caused by enzyme inactivation or a pH drop during the reaction but due to an instability of the cofactor NADP+. Although gluconic acid inhibited both NADPH production and oxidation by GDH and hydrogenase, respectively, it was not the major cause of NADP+ instability. Fructose was also shown to be converted to hydrogen if GI was present in the reaction mixture. Also, by starting with sucrose, 1. 34 mol of H2/mol of sucrose was obtained if GI was present in the reaction mixture. PMID:9841653

Woodward; Orr

1998-11-01

139

Modulation of Intestinal Inflammation by Yeasts and Cell Wall Extracts: Strain Dependence and Unexpected Anti-Inflammatory Role of Glucan Fractions  

Microsoft Academic Search

Yeasts and their glycan components can have a beneficial or adverse effect on intestinal inflammation. Previous research has shown that the presence of Saccharomyces cerevisiae var. boulardii (Sb) reduces intestinal inflammation and colonization by Candida albicans. The aim of this study was to identify dietary yeasts, which have comparable effects to the anti-C. albicans and anti-inflammatory properties of Sb and

Samir Jawhara; Khalid Habib; François Maggiotto; Georges Pignede; Pascal Vandekerckove; Emmanuel Maes; Laurent Dubuquoy; Thierry Fontaine; Yann Guerardel; Daniel Poulain

2012-01-01

140

A Systematic Review of Xuezhikang, an Extract from Red Yeast Rice, for Coronary Heart Disease Complicated by Dyslipidemia  

PubMed Central

Objective. This systematic review aims to evaluate the benefit and side effect of Xuezhikang for coronary heart disease (CHD) complicated by dyslipidemia. Methods. All randomized clinical trials (RCTs) with Xuezhikang as a treatment for CHD combined with dyslipidemia were considered for inclusion. Data extraction and analyses and quality assessment were conducted according to the Cochrane standards. Results. We included 22 randomized trials. Xuezhikang showed significant benefit on the incidence of all-cause deaths, CHD deaths, myocardial infarction, and revascularization as compared with placebo based on conventional treatment for CHD. It remarkably lowered total cholesterol (TC), triglyceride (TG), and low-density lipoprotein-cholesterol (LDL-C) as compared with the placebo or inositol nicotinate group, which was similar to statins group. Xuezhikang also raised high-density lipoprotein cholesterol (HDL-C) compared to placebo or no intervention, which was similar to Inositol nicotinate and slightly inferior to statins. The incidence of adverse events did not differ between the Xuezhikang and control group. Conclusions. Xuezhikang showed a comprehensive lipid-regulating effect and was safe and effective in reducing cardiovascular events in CHD patients complicated by dyslipidemia. However, more rigorous trials with high quality are needed to give high level of evidence.

Shang, Qinghua; Liu, Zhaolan; Chen, Keji; Xu, Hao; Liu, Jianping

2012-01-01

141

Sucrose-Utilizing Transglucosidases for Biocatalysis  

NASA Astrophysics Data System (ADS)

Sucrose-utilizing transglucosidases are valued tools in chemistry to generate glycodiversification. Not only do these enzymes use as substrate an abundant agroresource, sucrose, but they also share a remarkable versatility regarding the acceptor substrate, allowing the structurally-controlled synthesis of diverse glucosylated products. Latest research has demonstrated the potential of enzyme engineering to tailor novel sucrose-utilizing transglucosidases that give access to original carbohydrate-based structures. This chapter gives an overview of the recent achievements in biocatalysis using these enzymes.

André, Isabelle; Potocki-Véronèse, Gabrielle; Morel, Sandrine; Monsan, Pierre; Remaud-Siméon, Magali

142

Effects of different substrates on growth and glycerol production kinetics of a wine yeast strain Saccharomyces cerevisiae Narince 3  

Microsoft Academic Search

Glycerol, is important industrial product that can be produced using osmophilic yeasts. A study was carried out to determine the effects of glucose, fructose, and sucrose on growth and glycerol production kinetics of a wine yeast strain Saccharomyces cerevisiae Narince 3 in a batch system. Depending on the determined values of Monod constants, sucrose (Ks=44.53g\\/l) was the most suitable substrate

S. Karasu Yalçin; Z. Y. Özbas

2004-01-01

143

Complete sucrose hydrolysis by heat-killed recombinant Pichia pastoris cells entrapped in calcium alginate  

PubMed Central

Background An ideal immobilized biocatalyst for the industrial-scale production of invert sugar should stably operate at elevated temperatures (60-70°C) and high sucrose concentrations (above 60%, w/v). Commercial invertase from the yeast Saccharomyces cerevisiae is thermolabile and suffers from substrate inhibition. Thermotoga maritima ?-fructosidase (BfrA) is the most thermoactive and thermostable sucrose-hydrolysing enzyme so far identified and allows complete inversion of the substrate in highly concentrated solutions. Results In this study, heat-killed Pichia pastoris cells bearing N-glycosylated BfrA in the periplasmic space were entrapped in calcium alginate beads. The immobilized recombinant yeast showed maximal sucrose hydrolysis at pH 5–7 and 90°C. BfrA was 65% active at 60°C and had no activity loss after incubation without the substrate at this temperature for 15 h. Complete inversion of cane sugar (2.04 M) at 60°C was achieved in batchwise and continuous operation with respective productivities of 4.37 and 0.88 gram of substrate hydrolysed per gram of dry beads per hour. The half-life values of the biocatalyst were 14 and 20 days when operated at 60°C in the stirred tank and the fixed-bed column, respectively. The reaction with non-viable cells prevented the occurrence of sucrose fermentation and the formation of by-products. Six-month storage of the biocatalyst in 1.46 M sucrose (pH 5.5) at 4°C caused no reduction of the invertase activity. Conclusions The features of the novel thermostable biocatalyst developed in this study are more attractive than those of immobilized S. cerevisiae cells for application in the enzymatic manufacture of inverted sugar syrup in batch and fixed-bed reactors.

2014-01-01

144

Nonenzymatic Browning in Model Systems Containing Sucrose.  

National Technical Information Service (NTIS)

Freeze-dried systems containing sucrose and organic acids were found to undergo rapid nonenzymatic browning, even at low relative humidities. Addition of protein reduced the rate of browning, especially at low humidities. It was determined that the browni...

M. Karel T. P. Labuza

1968-01-01

145

Glucose tolerance factor extracted from yeast: oral insulin-mimetic and insulin-potentiating agent: in vivo and in vitro studies.  

PubMed

In search for an effective oral treatment for diabetes, we examined the capacity of glucose tolerance factor (GTF) extracted from yeast and administered orally to reduce hyperglycaemia in rat models exhibiting insulin deficiency. The cellular effect of GTF on the insulin signalling pathway was investigated in vitro. GTF (oral bolus), insulin (intraperitoneal) or their combination was administered to streptozotocin-diabetic (STZ) or hyperglycaemic Cohen diabetic-sensitive (hyp-CDs) rats. Blood glucose (BG) and insulin levels were measured in the postprandial (PP) state and during an oral glucose tolerance test. Deoxy-glucose transport and insulin signal transduction were assessed in 3T3-L1 adipocytes and myoblasts incubated with the GTF. Low dose of insulin produced a 34 and 12·5 % reduction in the PP-BG levels of hyp-CDs and STZ rats, respectively. GTF induced a 33 and 17 % reduction in the PP-BG levels of hyp-CDs and STZ rats, respectively. When combined with insulin, a respective decrease (58 and 42 %) in BG levels was observed, suggesting a partially additive (hyp-CDs) or synergistic (STZ rats) effect of the GTF and insulin. GTF did not induce insulin secretion in hyp-CDs rats, yet it lowered their BG levels, proposing an effect on glucose clearance by peripheral tissues. GTF induced a dose-dependent increase in deoxy-glucose transport into myoblasts and fat cells similar to insulin, while the combined treatment resulted in augmented transport rate. GTF induced a dose- and time-dependent phosphorylation of insulin receptor substrate 1, Akt and mitogen-activated protein kinase independent of insulin receptor phosphorylation. GTF exerts remarkable insulin-mimetic and insulin-potentiating effects, both in vivo and in vitro. It produces an insulin-like effect by acting on cellular signals downstream of the insulin receptor. These results demonstrate a potential source for a novel oral medication for diabetes. PMID:22172158

Weksler-Zangen, Sarah; Mizrahi, Tal; Raz, Itamar; Mirsky, Nitsa

2012-09-01

146

Sucrose phosphatase associated with vacuole preparations from red beet, sugar beet, and immature sugarcane stem.  

PubMed

The specific phosphatase, sucrose phosphate phosphohydrolase (sucrose phosphatase, EC 3.1.3.24) was present in vacuole preparations from storage tissue of red beet (Beta vulgaris L.), sugar beet (Beta vulgaris L. cultivar Kawemono), and immature sugarcane (Saccharum spp. hybrid, cultivar NCO 310). In red beet vacuole preparations the specific activity of sucrose phosphatase, using the naturally occurring vacuole marker, betanin, as reference, was higher than the specific activity of cytoplasmic markers, phosphoenolpyruvate carboxylase and glucose 6-phosphate dehydrogenase, suggesting that sucrose phosphatase is associated with the vacuoles. High speed centrifugation of lysed vacuoles did not result in precipitation of the enzyme indicating that the enzyme is not tightly bound to the tonoplast. Sucrose phosphatase was more sensitive to inhibition by sodium vanadate and less sensitive to ammonium molybdate than was the nonspecific phosphatase which was also present in the extracts. Sucrose phosphatase might be part of the group translocator proposed recently to operate in the tonoplast of sugarcane and red beet. PMID:16665598

Hawker, J S; Smith, G M; Phillips, H; Wiskich, J T

1987-08-01

147

Production of carotenoids by the isolated yeast of Rhodotorula glutinis  

Microsoft Academic Search

The production of carotenoids by the strain of Rhodotorula glutinis, a red soil yeast isolated from IPRA? refinery wastewater, was investigated in a batch system as a function of initial pH, temperature, aeration rate, initial sugar (glucose, molasses sucrose and whey lactose) and ammonium sulphate concentrations and activator (cotton seed oil and Tween 80) addition. Optimum pH and temperature for

Zümriye Aksu; Ay?e Tu?ba Eren

2007-01-01

148

Cinnamon extract inhibits ?-glucosidase activity and dampens postprandial glucose excursion in diabetic rats  

PubMed Central

Background ?-glucosidase inhibitors regulate postprandial hyperglycemia (PPHG) by impeding the rate of carbohydrate digestion in the small intestine and thereby hampering the diet associated acute glucose excursion. PPHG is a major risk factor for diabetic vascular complications leading to disabilities and mortality in diabetics. Cinnamomum zeylanicum, a spice, has been used in traditional medicine for treating diabetes. In this study we have evaluated the ?-glucosidase inhibitory potential of cinnamon extract to control postprandial blood glucose level in maltose, sucrose loaded STZ induced diabetic rats. Methods The methanol extract of cinnamon bark was prepared by Soxhlet extraction. Phytochemical analysis was performed to find the major class of compounds present in the extract. The inhibitory effect of cinnamon extract on yeast ?-glucosidase and rat-intestinal ?-glucosidase was determined in vitro and the kinetics of enzyme inhibition was studied. Dialysis experiment was performed to find the nature of the inhibition. Normal male Albino wistar rats and STZ induced diabetic rats were treated with cinnamon extract to find the effect of cinnamon on postprandial hyperglycemia after carbohydrate loading. Results Phytochemical analysis of the methanol extract displayed the presence of tannins, flavonoids, glycosides, terpenoids, coumarins and anthraquinones. In vitro studies had indicated dose-dependent inhibitory activity of cinnamon extract against yeast ?-glucosidase with the IC 50 value of 5.83 ?g/ml and mammalian ?-glucosidase with IC 50 value of 670 ?g/ml. Enzyme kinetics data fit to LB plot pointed out competitive mode of inhibition and the membrane dialysis experiment revealed reversible nature of inhibition. In vivo animal experiments are indicative of ameliorated postprandial hyperglycemia as the oral intake of the cinnamon extract (300 mg/kg body wt.) significantly dampened the postprandial hyperglycemia by 78.2% and 52.0% in maltose and sucrose loaded STZ induced diabetic rats respectively, compared to the control. On the other hand, in rats that received glucose and cinnamon extract, postprandial hyperglycemia was not effectively suppressed, which indicates that the observed postprandial glycemic amelioration is majorly due to ?-glucosidase inhibition. Conclusions The current study demonstrates one of the mechanisms in which cinnamon bark extract effectively inhibits ?-glucosidase leading to suppression of postprandial hyperglycemia in STZ induced diabetic rats loaded with maltose, sucrose. This bark extract shows competitive, reversible inhibition on ?-glucosidase enzyme. Cinnamon extract could be used as a potential nutraceutical agent for treating postprandial hyperglycemia. In future, specific inhibitor has to be isolated from the crude extract, characterized and therapeutically exploited.

2011-01-01

149

ESR investigation of sucrose radicals produced by particle irradiation  

Microsoft Academic Search

We investigated sucrose radicals produced by heavy-ion irradiation with various linear energy transfer (LETs) and the possibility for a sucrose electron spin resonance (ESR) dosimeter. The impact of heavy ions on sucrose produced sucrose radicals, which were measured by ESR. The obtained spectral pattern was the same as that for helium (He) ions, carbon (C) ions, neon (Ne) ions, iron

Kouichi Nakagawa; Yukio Sato

2004-01-01

150

Red yeast  

MedlinePLUS

... with this combination.Talk with your health provider.Cyclosporine (Neoral, Sandimmune)Red yeast might affect the muscles. Cyclosporine (Neoral, Sandimmune) might also affect the muscles. Taking ...

151

Yeast Infections  

MedlinePLUS

Candida is the scientific name for yeast. It is a fungus that lives almost everywhere, including in ... infection that causes white patches in your mouth Candida esophagitis is thrush that spreads to your esophagus, ...

152

Counting Yeast.  

ERIC Educational Resources Information Center

Describes changes to a traditional study of population in yeast colonies. Changes to the procedures include: (1) only one culture per student team; (2) cultures are inoculated only once; and (3) the same tube is sampled daily. (DDR)

Bealer, Jonathan; Welton, Briana

1998-01-01

153

Acid leaching of manganiferous ores by sucrose: Kinetic modelling and related statistical analysis  

Microsoft Academic Search

This work reports the kinetic study of a manganiferous ore leaching in acid media by sucrose as reducing agent.A shrinking core model with variable activation energy was found to successfully fit experimental data of manganese extraction yields vs leaching time. This model finds a physical confirmation both in the complex reactions that take place during manganese leaching and the different

F Beolchini; M. Petrangeli Papini; L Toro; M Trifoni; F Vegliò

2001-01-01

154

Application of polystyrene-bound invertase to continuous sucrose hydrolysis on pilot scale.  

PubMed

Invertase from baker's yeast (Saccharomyces cerevisiae) covalently bound to a macroporous polystyrene anion-exchange resin via glutaraldehyde was applied to continuous sucrose hydrolysis in packed bed-reactors. The process was scaled up from 3-mL laboratory reactors via 0.3-L reactors to pilot-scale 50-L reactors without significant loss of efficiency. The described process allows the production of a wide spectrum of invert sugar syrups with high purity in continuous procedure. The 50-L reactor was used under process conditions 1 year without significant loss of productivity at a temperature of 40 degrees C. A productivity of 760 g/h was obtained with 1 L invertase-polystyrene complex using a 2.5M sucrose solution as substrate. PMID:18601207

Mansfeld, J; Schellenberger, A; Römbach, J

1992-11-01

155

Sucrose/Glucose molecular alloys by cryomilling.  

PubMed

We report here for the first time a series of amorphous sucrose/glucose molecular alloys prepared by cryomilling. Differential scanning calorimetry, X-ray powder diffraction and solution proton nuclear magnetic resonance showed that cryomilling drives a direct transformation from a two-phase mixture of crystalline sucrose and glucose, to a single-phase amorphous sucrose/glucose molecular alloy. The molecular alloys displayed a single Tg which varied linearly with composition. The effect of atmospheric moisture and the possibility of localised melting of the material because of milling-related friction were also discussed. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:2098-2106, 2014. PMID:24867316

Megarry, Andrew J; Booth, Jonathan; Burley, Jonathan

2014-07-01

156

Substrate as a source of thermodynamic nonideality in enzyme kinetic studies: invertase-catalyzed hydrolysis of sucrose.  

PubMed

Expressions for the effects of thermodynamic nonideality arising from the use of high concentrations of small substrate in enzyme kinetic studies are derived. Their application to experimental results for the hydrolysis of sucrose by yeast invertase (pH 4.9, 37 degrees C) signifies that the progressive decrease in initial velocity at high sucrose concentration is consistent with the occurrence of isomeric expansion during the transition of an enzyme-substrate complex to its activated state. Ultracentrifuge studies on the yeast enzyme preparation are then used to establish the physical acceptability of the volume change required to account for the kinetic effects in these terms: the postulated expansion of 1.3 liter/mol would represent a mere 0.16% increase in hydrated volume (or a corresponding increase in extent of asymmetry). Finally, although originally interpreted to signify an effect of sucrose on water concentration, published results for the invertase-sucrose system [J. M. Nelson and M. P. Schubert (1928) J. Amer. Chem. Soc. 50, 2188-2193] also find a rational explanation in terms of the present analysis based on effects of thermodynamic nonideality in enzyme kinetic studies. PMID:3277534

Shearwin, K E; Winzor, D J

1988-02-01

157

Purification and Characterization of Sucrose Synthetase from the Shoot of Bamboo Leleba oldhami.  

PubMed

A 108-fold purification of the sucrose synthetase from the extract of the shoot of bamboo Lelaba oldhami was achieved by ammonium sulfate fractionation, calcium phosphate gel adsorption, and chromatographic separations on Sephadex G-100 and diethylaminoethyl-cellulose columns. Some properties of this enzyme, namely thermal and pH stabilities, stabilization by aqueous glycerol, pH optimum, substrate specificities, effects of metallic ions, effects of sulfhydryl reagents, molecular weight, sedimentation constants, isoelectric point, and substrate saturation kinetics had been investigated.The substrate saturation kinetics indicated that the enzyme could be an allosteric enzyme with the saccharide substrates (sucrose and fructose) serving as the homotropic allosteric effectors in regulating the biosynthesis and degradation of sucrose. PMID:16660030

Su, J C

1977-07-01

158

Effect of neem leaf extract and neem oil on Penicillium growth, sporulation, morphology and ochratoxin A production.  

PubMed

In vitro trials were conducted to evaluate the effect of Azadirachtaindica (neem) extracts on mycelial growth, sporulation, morphology and ochratoxin A production by P. verrucosum and P. brevicompactum. The effect of neem oil extract from seeds and leaf was evaluated at 0.125; 0.25 and 0.5% and 6.25 and 12.5 mg/mL, respectively, in Yeast Extract Sucrose (YES) medium. Ochratoxin A production was evaluated by a thin-layer chromatography technique. Oil extracts exhibited significant (p ? 0.05) reduction of growth and sporulation of the fungi. No inhibition of ochratoxin A production was observed. Given its accessibility and low cost, neem oil could be implemented as part of a sustainable integrated pest management strategy for plant disease, as it has been shown to be fungitoxic by inhibition of growth and sporulation. PMID:22069528

Mossini, Simone A G; Arrotéia, Carla C; Kemmelmeier, Carlos

2009-09-01

159

Role of glucose signaling in yeast metabolism  

SciTech Connect

The conversion of glucose to ethanol and carbon dioxide by yeast was the first biochemical pathway to be studied in detail. The initial observation that this process is catalyzed by an extract of yeast led to the discovery of enzymes and coenzymes and laid the foundation for modern biochemistry. In this article, knowledge concerning the relation between uptake of and signaling by glucose in the yeast Saccharomyces cerevisiae is reviewed and compared to the analogous process in prokaryotes. It is concluded that (much) more fundamental knowledge concerning these processes is required before rational redesign of metabolic fluxes from glucose in yeast can be achieved.

Dam, K. van [Univ. of Amsterdam (Netherlands). E.C. Slater Inst.

1996-10-05

160

Regulation of RhSUC2, a sucrose transporter, is correlated with the light control of bud burst in Rosa sp.  

PubMed

In roses, light is a central environmental factor controlling bud break and involves a stimulation of sugar metabolism. Very little is known about the role of sucrose transporters in the bud break process and its regulation by light. In this study, we show that sugar promotes rose bud break and that bud break is accompanied by an import of sucrose. Radio-labelled sucrose accumulation is higher in buds exposed to light than to darkness and involves an active component. Several sucrose transporter (RhSUC1, 2, 3 and 4) transcripts are expressed in rose tissues, but RhSUC2 transcript level is the only one induced in buds exposed to light after removing the apical dominance. RhSUC2 is preferentially expressed in bursting buds and stems. Functional analyses in baker's yeast demonstrate that RhSUC2 encodes a sucrose/proton co-transporter with a K(m) value of 2.99 mm at pH 4.5 and shows typical features of sucrose symporters. We therefore propose that bud break photocontrol partly depends upon the modulation of sucrose import into buds by RhSUC2. PMID:21635271

Henry, Clemence; Rabot, Amelie; Laloi, Maryse; Mortreau, Eric; Sigogne, Monique; Leduc, Nathalie; Lemoine, Rémi; Sakr, Soulaiman; Vian, Alain; Pelleschi-Travier, Sandrine

2011-10-01

161

Fermentation pattern of sucrose to ethanol conversions by Zymomonas mobilis  

SciTech Connect

General patterns of sucrose fermentation by two strains of Zymomonas mobilis, designated Z7 and Z10, were established using sucrose concentrations from 50 to 200 g/liter. Strain Z7 showed a higher invertase activity than Z10. Strain Z10 showed a reduced specific growth rate at high sucrose concentrations while Z7 was unaffected. High sucrose hydrolyzing activity in strain Z7 lead to glucose accumulation in the medium at high sucrose concentrations. Ethanol production and fermentation time depend on the rate of catabolism of the products of sucrose hydrolysis, glucose and fructose. The metabolic quotients for sucrose utilization, qs, and ethanol production, qp (g/g.hr), are unsuitable for describing sucrose utilization by Zymomonas mobilis as the logarithmic phase of growth precedes the phase of highest substrate utilization (g/liter.hr) and ethanol production (g/liter.hr) in batch culture. (Refs. 10).

Lyness, E.; Doelle, H.W.

1981-07-01

162

Chronic sucrose ingestion enhances mu-opioid discriminative stimulus effects.  

PubMed

Sucrose affects a variety of opioid-related behaviors. We hypothesized that, if sucrose ingestion alters opioidergic circuitry, opioid-induced discriminative stimulus effects would be enhanced following sucrose intake. In the present study, rats were trained to discriminate nalbuphine (3.2 mg/kg, s.c.) from saline in an operant choice procedure. After acquiring the discrimination, subjects were injected with a single nalbuphine dose (0.1-3.2 mg/kg) and given 30-min access to 30% sucrose or water. Sucrose consumption did not alter nalbuphine's discriminative stimulus effects under these conditions. During subsequent tests, training was suspended, and rats received continuous access to sucrose (9 days) or water (8 days). Chronic sucrose consumption increased the potency of nalbuphine to produce its discriminative stimulus effects by 3-fold. These findings suggest chronic sucrose consumption results in changes in opioid-system function that modulates the effects of exogenously administered opioids. PMID:15967419

Jewett, David C; Grace, Martha K; Levine, Allen S

2005-07-19

163

The Enzyme-Catalyzed Synthesis of Sucrose from Starch.  

National Technical Information Service (NTIS)

The most abundant food sugar is sucrose and world demand for sucrose and other sweeteners has outstripped production. Commercial processes have been developed for enzymic production of glucose-fructose mixtures from cornstarch. This report very briefly de...

S. J. Kelly L. G. Butler R. G. Squires

1976-01-01

164

Studies on the 'osmophilic' yeast saccharomyces rouxii and an obligate osmophilic mutant.  

PubMed

An obilagte osmophilic mutant (strain BI/4) of Saccharomyces rouxii has been isolated that fails to grow at osmotic pressures corresponding to 20 per cent (w/v) sucrose or less. In 30 percent sucrose the yeast is filamentous and grows slowly. In 40percent sucrose it is mainly filamentous and has over twice the normal diameter. In 60 percentsucrose it grows in the yeast form with a growth rate twic that of the cultrue in 40 per cent sucrose. This mutant is lysed by a suddren drop in the osmotic pressure of the environment. Cell enveoples of the parent strain contained glucose and manose in the ratio I.2; Iand contained 3-8percent (w/v) hexosamine, whereas the envelopes of the mutatn contained 0-8 percent hexosaime. Cell envelopes of the mutant grown in 40 per cent sucrose contained glucose and mannose in the ratioI.9; I, wheras for envelopes of the yeast grown in 60 percent sucrose the ratio was I.2; I. Neutral lipids from whole cells and those from the envelopes of the mutant strain generally contained more unsaturated fatty acids than the corresponding fractions from the parent strain. PMID:1151327

Koh, T Y

1975-05-01

165

Nanocomposites from natural cellulose fibers incorporated with sucrose  

Microsoft Academic Search

The present work shows for the first time worldwide that sucrose can be easily placed by simple techniques within the micropores\\u000a or nanostructure of the mercerized non-dried cotton linter fibers to create a low-cost cellulose substitute. Such sucrose-containing\\u000a nanocomposites find suitable use as specialty absorbent paper. Relative to the sucrose-free paper, the sucrose-containing\\u000a counterparts exhibit greater breaking length and remarkably

Tamer Y. A. Fahmy; Fardous Mobarak; Yehia Fahmy; M. H. Fadl; M. El-Sakhawy

2006-01-01

166

Phloem loading of sucrose: Update and opportunities in molecular biology  

Microsoft Academic Search

Sucrose accumulates in the phloem against a concentration gradient via a presumed sucrose-specific carrier protein located\\u000a at the plasmalemma of the sieve elements\\/companion cells. Recent evidence suggests that sucrose carrier in soybean is a 62-kDa\\u000a protein. Immunocytochemical localization has shown the protein to be exclusively at the plasmalemma, which is also the site\\u000a of sucrose transport. To enhance our understanding

Jaleh Daie

1989-01-01

167

Sucrose Phosphate Synthase, Sucrose Synthase, and Invertase Activities in Developing Fruit of Lycopersicon esculentum Mill. and the Sucrose Accumulating Lycopersicon hirsutum Humb. and Bonpl. 1  

PubMed Central

The green-fruited Lycopersicon hirsutum Humb. and Bonpl. accumulated sucrose to concentrations of about 118 micromoles per gram fresh weight during the final stages of development. In comparison, Lycopersicon esculentum Mill. cultivars contained less than 15 micromoles per gram fresh weight of sucrose at the ripe stage. Glucose and fructose levels remained relatively constant throughout development in L. hirsutum at 22 to 50 micromoles per gram fresh weight each. Starch content was low even at early stages of development, and declined further with development. Soluble acid invertase (EC 3.2. 1.26) activity declined concomitant with the rise in sucrose content. Acid invertase activity, which was solubilized in 1 molar NaCl (presumably cell-wall bound), remained constant throughout development (about 3 micromoles of reducing sugars (per gram fresh weight) per hour. Sucrose phosphate synthase (EC 2.4.1.14) activity was present at about 5 micromoles of sucrose (per gram fresh weight) per hour even at early stages of development, and increased sharply to about 40 micromoles of sucrose (per gram fresh weight) per hour at the final stages of development studied, parallel to the rise in sucrose content. In comparison, sucrose phosphate synthase activity in L. esculentum remained low throughout development. The possible roles of the sucrose metabolizing enzymes in determining sucrose accumulation are discussed.

Miron, Daphne; Schaffer, Arthur A.

1991-01-01

168

Modulation of Intestinal Inflammation by Yeasts and Cell Wall Extracts: Strain Dependence and Unexpected Anti-Inflammatory Role of Glucan Fractions  

PubMed Central

Yeasts and their glycan components can have a beneficial or adverse effect on intestinal inflammation. Previous research has shown that the presence of Saccharomyces cerevisiae var. boulardii (Sb) reduces intestinal inflammation and colonization by Candida albicans. The aim of this study was to identify dietary yeasts, which have comparable effects to the anti-C. albicans and anti-inflammatory properties of Sb and to assess the capabilities of yeast cell wall components to modulate intestinal inflammation. Mice received a single oral challenge of C. albicans and were then given 1.5% dextran-sulphate-sodium (DSS) for 2 weeks followed by a 3-day restitution period. S. cerevisiae strains (Sb, Sc1 to Sc4), as well as mannoprotein (MP) and ?-glucan crude fractions prepared from Sc2 and highly purified ?-glucans prepared from C. albicans were used in this curative model, starting 3 days after C. albicans challenge. Mice were assessed for the clinical, histological and inflammatory responses related to DSS administration. Strain Sc1-1 gave the same level of protection against C. albicans as Sb when assessed by mortality, clinical scores, colonization levels, reduction of TNF? and increase in IL-10 transcription. When Sc1-1 was compared with the other S. cerevisiae strains, the preparation process had a strong influence on biological activity. Interestingly, some S. cerevisiae strains dramatically increased mortality and clinical scores. Strain Sc4 and MP fraction favoured C. albicans colonization and inflammation, whereas ?-glucan fraction was protective against both. Surprisingly, purified ?-glucans from C. albicans had the same protective effect. Thus, some yeasts appear to be strong modulators of intestinal inflammation. These effects are dependent on the strain, species, preparation process and cell wall fraction. It was striking that ?-glucan fractions or pure ?-glucans from C. albicans displayed the most potent anti-inflammatory effect in the DSS model.

Jawhara, Samir; Habib, Khalid; Maggiotto, Francois; Pignede, Georges; Vandekerckove, Pascal; Maes, Emmanuel; Dubuquoy, Laurent; Fontaine, Thierry; Guerardel, Yann; Poulain, Daniel

2012-01-01

169

Single-cell protein production from Jerusalem artichoke extract by a recently isolated marine yeast Cryptococcus aureus G7a and its nutritive analysis  

Microsoft Academic Search

After crude protein of the marine yeast strains maintained in this laboratory was estimated by the method of Kjehldahl, we\\u000a found that the G7a strain which was identified to be a strain of Cryptococcus aureus according to the routine identification and molecular methods contained high level of protein and could grow on a wide range\\u000a of carbon sources. The optimal

Lingmei Gao; Zhenming Chi; Jun Sheng; Xiumei Ni; Lin Wang

2007-01-01

170

Functional characterization of sucrose phosphorylase and scrR, a regulator of sucrose metabolism in Lactobacillus reuteri.  

PubMed

Lactobacillus reuteri harbours alternative enzymes for sucrose metabolism, sucrose phosphorylase, fructansucrases, and glucansucrases. Sucrose phosphorylase and fructansucrases additionally contribute to raffinose metabolism. Glucansucrases and fructansucrases produce exopolysaccharides as alternative to sucrose hydrolysis. L. reuteri LTH5448 expresses a levansucrase (ftfA) and sucrose phosphorylase (scrP), both are inducible by sucrose. This study determined the contribution of scrP to sucrose and raffinose metabolism in L. reuteri LTH5448, and elucidated the role of scrR in regulation sucrose metabolism. Disruption of scrP and scrR was achieved by double crossover mutagenesis. L. reuteri LTH5448, LTH5448?scrP and LTH5448?scrR were characterized with respect to growth and metabolite formation with glucose, sucrose, or raffinose as sole carbon source. Inactivation of scrR led to constitutive transcription of scrP and ftfA, demonstrating that scrR is negative regulator. L. reuteri LTH5448 and the LTH5448?scrP or LTH5448?scrR mutant strains did not differ with respect to glucose, sucrose or raffinose utilization. However, L. reuteri LTH5448?scrP produced more levan, indicating that the lack of sucrose phosphorylase is compensated by an increased metabolic flux through levansucrase. In conclusion, the presence of alternate pathways for sucrose and raffinose metabolism and their regulation indicate that these substrates, which are abundant in plants, are preferred carbohydrate sources for L. reuteri. PMID:24010626

Teixeira, Januana S; Abdi, Reihaneh; Su, Marcia Shu-Wei; Schwab, Clarissa; Gänzle, Michael G

2013-12-01

171

Sucrose-water mixture: From thermodynamics to solution structure  

NASA Astrophysics Data System (ADS)

What is the structure of sucrose-water mixture? I employ an exact statistical thermodynamic theory (Kirkwood-Buff theory) to calculate information regarding sucrose-water, water-water and sucrose-sucrose interactions solely from volumetric and osmometric data. We found that (i) Long-ranged hydration structure, beyond the first hydration shell, influences thermodynamics; (ii) The inferred minimum of the activity coefficient of water at the high sucrose concentration is due to the increases in the self association of water. These findings from a rigorous theory are consistent with previous simulation studies.

Shimizu, Seishi

2013-09-01

172

Sucrose deficiency delays lycopene accumulation in tomato fruit pericarp discs.  

PubMed

Tomato (Solanum lycopersicum) fruit ripening is characterized by a massive accumulation of carotenoids (mainly lycopene) as chloroplasts change to chromoplasts. To address the question of the role of sugars in controlling carotenoid accumulation, fruit pericarp discs (mature green fruits) were cultured in vitro in the presence of various sucrose concentrations. A significant difference in soluble sugar content was achieved depending on external sucrose availability. Sucrose limitation delayed and reduced lycopene and phytoene accumulation, with no significant effect on other carotenoids. Chlorophyll degradation and starch catabolism were not affected by variations of sucrose availability. The reduction of lycopene synthesis observed in sucrose-limited conditions was mediated through metabolic changes illustrated by reduced hexose accumulation levels. In addition, variations of sucrose availability modulated PSY1 gene expression. Taken together our results suggest that the modulation of carotenoid accumulation by sucrose availability occurs at the metabolic level and involves the differential regulation of genes involved in carotenoid biosynthesis. PMID:16915514

Télef, Nadège; Stammitti-Bert, Linda; Mortain-Bertrand, Anne; Maucourt, Mickaël; Carde, Jean Pierre; Rolin, Dominique; Gallusci, Philippe

2006-10-01

173

Does sucrose influence the properties of DMPC vesicles?  

PubMed

Small-angle neutron and X-ray scattering, dynamic light scattering, X-ray diffraction coupled with differential scanning calorimetry, and Raman spectroscopy were applied to investigate unilamellar (ULVs) and multilamellar (MLVs) dimyristoylphosphatidylcholine (DMPC) vesicles in aqueous sucrose solutions with sucrose concentrations from 0 to 60% w/w. In case of ULVs, the addition of sucrose decreases the polydispersity of vesicle population. A minimum value of polydispersity was found at 20% sucrose. For sucrose concentration from 0 to 35% oligolamellar vesicles in the ULV population have a minimum presence. Vesicles with 5-10% sucrose exhibit the best stability in time. For the case of MLVs, sucrose influences the temperature of the phase transitions, but the internal membrane structure remains unchanged. PMID:12637163

Kiselev, M A; Wartewig, S; Janich, M; Lesieur, P; Kiselev, A M; Ollivon, M; Neubert, R

2003-03-01

174

High power density yeast catalyzed microbial fuel cells  

NASA Astrophysics Data System (ADS)

Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density increase was shown to quickly saturate with cell mass attached on the electrode. Based on recent modelling data that suggested that the electrode currents might be limited by the poor electrical conductivity of the anode, the power density versus electrical conductivity of a yeast-immobilized anode was investigated. Introduction of high aspect ratio carbon fiber filaments to the immobilization matrix increased the electrical conductivity of the anode. Although a higher electrical conductivity clearly led to an increase in power densities, it was shown that the principal limitation to power density increase was coming from proton transfer limitations in the immobilized anode. Partial overcoming of the gradients lead a power density of ca. 250 microW cm-2, which is the highest reported for yeast powered MFCs. A yeast-catalyzed microbial fuel cell was investigated as a power source for low power sensors using raw tree sap. It was shown that yeast can efficiently utilize the sucrose present in the raw tree sap to produce electricity when excess salt is added to the medium. Therefore the salinity of a potential energy source is an important consideration when MFCs are being considered for energy harvesting from natural sources.

Ganguli, Rahul

175

Ras Signaling in Yeast  

PubMed Central

Since the study of yeast RAS and adenylate cyclase in the early 1980s, yeasts including budding and fission yeasts contributed significantly to the study of Ras signaling. First, yeast studies provided insights into how Ras activates downstream signaling pathways. Second, yeast studies contributed to the identification and characterization of GAP and GEF proteins, key regulators of Ras. Finally, the study of yeast provided many important insights into the understanding of C-terminal processing and membrane association of Ras proteins.

Tamanoi, Fuyuhiko

2011-01-01

176

Expression, purification and characterization of recombinant sucrose synthase 1 from Solanum tuberosum L. for carbohydrate engineering  

Microsoft Academic Search

The gene sus1 from Solanum tuberosum L. encoding for sucrose synthase 1 was cloned into the plasmid pDR195 under the control of the PMA1 promotor. After transformation of Saccharomyces cerevisiae strain 22574d sus1 was constitutively expressed giving a specific activity of 0.3Umg(-1) protein in the crude extract. A one-step purification by Q-Sepharose resulted in an 14-fold purified enzyme preparation in

U. Römer; Henning Schrader; N. Günther; Nadja Nettelstroth; Wolf B Frommer; Lothar Elling

2004-01-01

177

Assessment of extracts from red yeast rice for herb-drug interaction by in-vitro and in-vivo assays.  

PubMed

Red yeast rice (RYR) is made by fermenting the yeast Monascus purpureus over rice. It is a source of natural red food colorants, a food garnish and a traditional medication. Results of the current study demonstrated that polar fractions of the RYR preparations contained herbal-drug interaction activity, which if left unremoved, enhanced P-glycoprotein activity and inhibited the major drug metabolizing cytochromes P450, i,e, CYP 1A2, 2C9 and 3A4. The data from Caco-2 cell absorption and animal model studies further demonstrated that the pharmacokinetic modulation effect by RYR preparations containing the polar fractions ("untreated" preparation) was greater than that from RYR preparations with the polar fractions removed ("treated" preparation). The data indicates a potential for herb-drug interactions to be present in RYR commonly sold as nutritional supplements when the polar fractions are not removed and this should be taken into consideration when RYR is consumed with medications, including verapamil. PMID:22389767

Fung, Wai To; Subramaniam, G; Lee, Joel; Loh, Heng Meng; Leung, Pak Ho Henry

2012-01-01

178

Transcription factors, sucrose, and sucrose metabolic genes interact to regulate potato phenylpropanoid metabolism  

PubMed Central

Much remains unknown about how transcription factors and sugars regulate phenylpropanoid metabolism in tuber crops like potato (Solanum tuberosum). Based on phylogeny and protein similarity to known regulators of phenylpropanoid metabolism, 15 transcription factors were selected and their expression was compared in white, yellow, red, and purple genotypes with contrasting phenolic and anthocyanin profiles. Red and purple genotypes had increased phenylalanine ammonia lyase (PAL) enzyme activity, markedly higher levels of phenylpropanoids, and elevated expression of most phenylpropanoid structural genes, including a novel anthocyanin O-methyltransferase. The transcription factors Anthocyanin1 (StAN1), basic Helix Loop Helix1 (StbHLH1), and StWD40 were more strongly expressed in red and purple potatoes. Expression of 12 other transcription factors was not associated with phenylpropanoid content, except for StMYB12B, which showed a negative relationship. Increased expression of AN1, bHLH1, and WD40 was also associated with environmentally mediated increases in tuber phenylpropanoids. Treatment of potato plantlets with sucrose induced hydroxycinnamic acids, flavonols, anthocyanins, structural genes, AN1, bHLH1, WD40, and genes encoding the sucrose-hydrolysing enzymes SUSY1, SUSY4, and INV2. Transient expression of StAN1 in tobacco leaves induced bHLH1, structural genes, SUSY1, SUSY4, and INV1, and increased phenylpropanoid amounts. StAN1 infiltration into tobacco leaves decreased sucrose and glucose concentrations. In silico promoter analysis revealed the presence of MYB and bHLH regulatory elements on sucrolytic gene promoters and sucrose-responsive elements on the AN1 promoter. These findings reveal an interesting dynamic between AN1, sucrose, and sucrose metabolic genes in modulating potato phenylpropanoids.

Payyavula, Raja S.; Navarre, Duroy A.

2013-01-01

179

Sugar Content and Activity of Sucrose Metabolism Enzymes in Milled Rice Grain  

PubMed Central

Most rice (Oryza sativa L.) cultivars grown in the United States were selected for endosperm starch properties and not soluble sugar content. The minor pool of soluble sugar may affect the qualities of rice as a food. Some cultivar variation in soluble sugar content was detected in milled grain, essentially the starchy endosperm, of long grain varieties. Milled grain of cultivars Lemont and Texmati had a soluble sugar content of 0.21 and 0.35% (w/w), respectively, on a fresh weight basis. The dorsal portion of the milled grain contained the greatest amount of soluble sugar, approximately tenfold the amount found in the central core of the grain. Extracts of the milled grain contained sucrose-phosphate synthase (EC 2.4.1.14) and sucrose synthase (EC 2.4.1.13) activities, which were separated by anion exchange chromatography. The presence of sucrose-phosphate synthase in the rice endosperm suggested a mechanism for sucrose accumulation which might be involved in carbon partitioning during grain development. Images Figure 3

Smyth, Douglas A.; Prescott, Henry E.

1989-01-01

180

Effect of salt on the response of birds to sucrose  

USGS Publications Warehouse

The preference of male red-winged blackbirds for solutions of sucrose and sucrose with 0.03 M sodium chloride was tested, using a two-bottle choice test. Preliminary experiments demonstrated that the birds were indifferent to 0.03 M NaCl in water. Both control and experimental animals exhibited indifference to the solutions at the lowest concentration and aversion at the highest. The data suggest that the added sodium chloride makes the sucrose stimulus more discriminable.

Rogers, J.G., Jr.; Maller, O.

1973-01-01

181

Determination of Bitrex, Quassia Powder and Sucrose Octaacetate Next to Diethyl Phthalate and Camphor in Specially Denatured Alcohols by Liquid Chromatografhy  

Microsoft Academic Search

A HPLC method for determination of the bitter principles, bitrex, quassia and sucrose octaacetate, next to other ingredients in Specially Denatured Alcohol formulations is described. The method is based on evaporation of a sample, extraction of the residue with hexane and analysis of the extracted residue on a Cyano-type column with acetonitrile-water used as the eluent. Baseline separation of compounds

Jan Kovar; Mireille Loyer

1984-01-01

182

Comparison of foaming and interfacial properties of pure sucrose monolaurates, dilaurate and commercial preparations  

Microsoft Academic Search

The functional properties of a commercially available, crude sucrose monolaurate (L1695) were studied by investigating the foaming, and interfacial properties i.e. surface tension, thin film drainage, thickness and mobility, and comparing them with the properties of pure sucrose monolaurate isomers and sucrose dilaurate. Both pure sucrose monoester isomers studied exhibited similar foaming and interfacial properties. In comparison, sucrose dilaurate displayed

F. A. Husband; D. B. Sarney; M. J. Barnard; P. J. Wilde

1998-01-01

183

Biosynthesis of Levan, a Bacterial Extracellular Polysaccharide, in the Yeast Saccharomyces cerevisiae  

PubMed Central

Levans are fructose polymers synthesized by a broad range of micro-organisms and a limited number of plant species as non-structural storage carbohydrates. In microbes, these polymers contribute to the formation of the extracellular polysaccharide (EPS) matrix and play a role in microbial biofilm formation. Levans belong to a larger group of commercially important polymers, referred to as fructans, which are used as a source of prebiotic fibre. For levan, specifically, this market remains untapped, since no viable production strategy has been established. Synthesis of levan is catalysed by a group of enzymes, referred to as levansucrases, using sucrose as substrate. Heterologous expression of levansucrases has been notoriously difficult to achieve in Saccharomyces cerevisiae. As a strategy, this study used an invertase (?suc2) null mutant and two separate, engineered, sucrose accumulating yeast strains as hosts for the expression of the levansucrase M1FT, previously cloned from Leuconostoc mesenteroides. Intracellular sucrose accumulation was achieved either by expression of a sucrose synthase (Susy) from potato or the spinach sucrose transporter (SUT). The data indicate that in both ?suc2 and the sucrose accumulating strains, the M1FT was able to catalyse fructose polymerisation. In the absence of the predicted M1FT secretion signal, intracellular levan accumulation was significantly enhanced for both sucrose accumulation strains, when grown on minimal media. Interestingly, co-expression of M1FT and SUT resulted in hyper-production and extracellular build-up of levan when grown in rich medium containing sucrose. This study presents the first report of levan production in S. cerevisiae and opens potential avenues for the production of levan using this well established industrial microbe. Furthermore, the work provides interesting perspectives when considering the heterologous expression of sugar polymerizing enzymes in yeast.

Franken, Jaco; Brandt, Bianca A.; Tai, Siew L.; Bauer, Florian F.

2013-01-01

184

Biosynthesis of levan, a bacterial extracellular polysaccharide, in the yeast Saccharomyces cerevisiae.  

PubMed

Levans are fructose polymers synthesized by a broad range of micro-organisms and a limited number of plant species as non-structural storage carbohydrates. In microbes, these polymers contribute to the formation of the extracellular polysaccharide (EPS) matrix and play a role in microbial biofilm formation. Levans belong to a larger group of commercially important polymers, referred to as fructans, which are used as a source of prebiotic fibre. For levan, specifically, this market remains untapped, since no viable production strategy has been established. Synthesis of levan is catalysed by a group of enzymes, referred to as levansucrases, using sucrose as substrate. Heterologous expression of levansucrases has been notoriously difficult to achieve in Saccharomyces cerevisiae. As a strategy, this study used an invertase (?suc2) null mutant and two separate, engineered, sucrose accumulating yeast strains as hosts for the expression of the levansucrase M1FT, previously cloned from Leuconostoc mesenteroides. Intracellular sucrose accumulation was achieved either by expression of a sucrose synthase (Susy) from potato or the spinach sucrose transporter (SUT). The data indicate that in both ?suc2 and the sucrose accumulating strains, the M1FT was able to catalyse fructose polymerisation. In the absence of the predicted M1FT secretion signal, intracellular levan accumulation was significantly enhanced for both sucrose accumulation strains, when grown on minimal media. Interestingly, co-expression of M1FT and SUT resulted in hyper-production and extracellular build-up of levan when grown in rich medium containing sucrose. This study presents the first report of levan production in S. cerevisiae and opens potential avenues for the production of levan using this well established industrial microbe. Furthermore, the work provides interesting perspectives when considering the heterologous expression of sugar polymerizing enzymes in yeast. PMID:24147008

Franken, Jaco; Brandt, Bianca A; Tai, Siew L; Bauer, Florian F

2013-01-01

185

Effects of sucrose and urea on soy hull pectic polysaccharide gel induced by D-glucono-1,5-lactone.  

PubMed

Gelation properties of pectic polysaccharide extracted with ammonium oxalate from soybean hulls assisted by microwave were seldom studied. Water mobility in soy hull pectic polysaccharide (SHPP) was firstly studied by low field NMR. D-Glucono-1,5-lactone (GDL) and sucrose both could decrease spin-spin relaxation times (T2) of SHPP solutions which indicated the SHPP network formed. Rheological analysis conformed that SHPP gel was formed induced by GDL and enhanced by sucrose. Urea can increase T2 and collapse the network of SHPP. TGA was used to draw the profiles of water desorption from SHPP solutions or gels, during heating at a controlled rate. It was found that sucrose increased the bound water content and urea acted a conversely role. Hydrogen bond is the main force to maintain SHPP gel network. PMID:23987379

Liu, He; Li, Qinghua; Zhu, Danshi; Li, Jun; Liu, Junshan; Geng, Ping; He, Yutang

2013-10-15

186

Comparative Sucrose Responsiveness in Apis mellifera and A. cerana Foragers  

PubMed Central

In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources.

Yang, Wenchao; Kuang, Haiou; Wang, Shanshan; Wang, Jie; Liu, Wei; Wu, Zhenhong; Tian, Yuanyuan; Huang, Zachary Y.; Miao, Xiaoqing

2013-01-01

187

Comparative sucrose responsiveness in Apis mellifera and A. cerana foragers.  

PubMed

In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources. PMID:24194958

Yang, Wenchao; Kuang, Haiou; Wang, Shanshan; Wang, Jie; Liu, Wei; Wu, Zhenhong; Tian, Yuanyuan; Huang, Zachary Y; Miao, Xiaoqing

2013-01-01

188

Single cell protein production from yacon extract using a highly thermosensitive and permeable mutant of the marine yeast Cryptococcus aureus G7a and its nutritive analysis  

Microsoft Academic Search

The intracellular protein in the highly thermosensitive and permeable mutant can be easily released when they are incubated\\u000a both in the low-osmolarity water and at the non-permissive temperature (usually 37 °C). After the mutant was grown in the\\u000a yacon extract for 45 h, the crude protein content in the highly thermosensitive and permeable mutant Z114 was 59.1% and over\\u000a 61% of the

Chun-Hai Zhao; Tong Zhang; Zhen-Ming Chi; Zhe Chi; Jing Li; Xiang-Hong Wang

2010-01-01

189

Light/Dark Profiles of Sucrose Phosphate Synthase, Sucrose Synthase, and Acid Invertase in Leaves of Sugar Beets  

PubMed Central

The activity of sucrose phosphate synthase, sucrose synthase, and acid invertase was monitored in 1- to 2-month-old sugar beet (Beta vulgaris L.) leaves. Sugar beet leaves achieve full laminar length in 13 days. Therefore, leaves were harvested at 2-day intervals for 15 days. Sucrose phosphate synthase activity was not detectable for 6 days in the dark-grown leaves. Once activity was measurable, sucrose phosphate synthase activity never exceeded half that observed in the light-grown leaves. After 8 days in the dark, leaves which were illuminated for 30 minutes showed no significant change in sucrose phosphate synthase activity. Leaves illuminated for 24 hours after 8 days in darkness, however, recovered sucrose phosphate synthase activity to 80% of that of normally grown leaves. Sucrose synthase and acid invertase activity in the light-grown leaves both increased for the first 7 days and then decreased as the leaves matured. In contrast, the activity of sucrose synthase oscillated throughout the growth period in the dark-grown leaves. Acid invertase activity in the dark-grown leaves seemed to be the same as the activity found in the light-grown leaves.

Vassey, Terry L.

1989-01-01

190

40 CFR 180.1222 - Sucrose octanoate esters; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Sucrose octanoate esters; exemption from the...Exemptions From Tolerances § 180.1222 Sucrose octanoate esters; exemption from the...tolerance is established for residues of sucrose octanoate esters...

2009-07-01

191

Yeast communities in a natural tequila fermentation.  

PubMed

Fresh and cooked agave, Drosophila spp., processing equipment, agave molasses, agave extract, and fermenting must at a traditional tequila distillery (Herradura, Amatitan, Jalisco, México) were studied to gain insight on the origin of yeasts involved in a natural tequila fermentations. Five yeast communities were identified. (1) Fresh agave contained a diverse mycobiota dominated by Clavispora lusitaniae and an endemic species, Metschnikowia agaveae. (2) Drosophila spp. from around or inside the distillery yielded typical fruit yeasts, in particular Hanseniaspora spp., Pichia kluyveri, and Candida krusei. (3) Schizosaccharomyces pombe prevailed in molasses. (4) Cooked agave and extract had a considerable diversity of species, but included Saccharomyces cerevisiae. (5) Fermenting juice underwent a gradual reduction in yeast heterogeneity. Torulaspora delbrueckii, Kluyveromyces marxianus, and Hanseniaspora spp. progressively ceded the way to S. cerevisiae, Zygosaccharomyces bailii, Candida milleri, and Brettanomyces spp. With the exception of Pichia membranaefaciens, which was shared by all communities, little overlap existed. That separation was even more manifest when species were divided into distinguishable biotypes based on morphology or physiology. It is concluded that crushing equipment and must holding tanks are the main source of significant inoculum for the fermentation process. Drosophila species appear to serve as internal vectors. Proximity to fruit trees probably contributes to maintaining a substantial Drosophila community, but the yeasts found in the distillery exhibit very little similarity to those found in adjacent vegetation. Interactions involving killer toxins had no apparent direct effects on the yeast community structure. PMID:8546452

Lachance, M A

1995-08-01

192

Yeast Infection (Candidiasis)  

MedlinePLUS

... for adults A A A This is a candida (yeast) infection of the skin folds of the ... infection with the common yeast (or fungus) organism, Candida albicans, which is commonly found in the environment. ...

193

Phenoptosis in yeasts.  

PubMed

The current view on phenoptosis and apoptosis as genetic programs aimed at eliminating potentially dangerous organisms and cells, respectively, is given. Special emphasis is placed on apoptosis (phenoptosis) in yeasts: intracellular defects and a plethora of external stimuli inducing apoptosis in yeasts; distinctive morphological and biochemical hallmarks accompanying apoptosis in yeasts; pro- and antiapoptotic factors involved in yeast apoptosis signaling; consecutive stages of apoptosis from external stimulus to the cell death; a prominent role of mitochondria and other organelles in yeast apoptosis; possible pathways for release of apoptotic factors from the intermembrane mitochondrial space into the cytosol are described. Using some concrete examples, the obvious physiological importance and expediency of altruistic death of yeast cells is shown. Poorly known aspects of yeast apoptosis and prospects for yeast apoptosis study are defined. PMID:22817540

Sukhanova, E I; Rogov, A G; Severin, F F; Zvyagilskaya, R A

2012-07-01

194

Yeast Based Sensors  

NASA Astrophysics Data System (ADS)

Since the first microbial cell sensor was studied by Karube et al. in 1977, many types of yeast based sensors have been developed as analytical tools. Yeasts are known as facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions. The yeast based sensor consisted of a DO electrode and an immobilized omnivorous yeast. In yeast based sensor development, many kinds of yeast have been employed by applying their characteristics to adapt to the analyte. For example, Trichosporon cutaneum was used to estimate organic pollution in industrial wastewater. Yeast based sensors are suitable for online control of biochemical processes and for environmental monitoring. In this review, principles and applications of yeast based sensors are summarized.

Shimomura-Shimizu, Mifumi; Karube, Isao

195

Quantitative production of xylitol from D-xylose by a high-xylitol producing yeast mutant Candida tropicalis HXP2  

Microsoft Academic Search

Xylitol was produced as a metabolic by-product by a number of yeasts when grown on medium containing D-xylose as carbon and energy sources. Among the yeast strains tested, a mutant strain of Candida tropicalis (HXP2) was found to produce xylitol from D-xylose with a high yield (>90%). Ethanol was also produced by HXP2 when D-glucose, D-fructose, or sucrose were used

Cheng-Shung Gong; Li Fu Chen; George T. Tsao

1981-01-01

196

Lager brewing yeast  

Microsoft Academic Search

Lager brewing yeast is a group of closely related strains of Saccharomyces pastorianus\\/S. carlsbergensis used for lager beer production all over the world, making it one of the most important industrial yeasts. The pure cultivation\\u000a of yeast was established in the early 1880’s with immediate practical success for lager brewing yeast. However, almost a century\\u000a would elapse before its genetics

Yukiko Kodama; Morten C. Kielland-Brandt; Jørgen Hansen

197

SUT Sucrose and MST Monosaccharide Transporter Inventory of the Selaginella Genome  

PubMed Central

Most metazoa use hexose transporters to acquire hexoses from their diet and as a transport form for distributing carbon and energy within their bodies; insects use trehalose, and plants use sucrose as their major form for translocation. Plant genomes contain at least three families of mono- and disaccharide transporters: monosaccharide/polyol transporters that are evolutionary closely related to the yeast and human glucose transporters, sucrose transporters of the SUT family, which similar to the hexose transporters belong to the major facilitator superfamily, but share only minimal amino acid sequence homology with the hexose transporters, and the family of SWEET sugar transporters conserved between animals and plants. Recently, the genome sequence of the spikemoss Selaginella has been determined. In order to study the evolution of sugar transport in plants, we carefully annotated of the complement of sugar transporters in Selaginella. We review the current knowledge regarding sugar transport in spikemoss and provide phylogenetic analyses of the complement of MST and SUT homologs in Selaginella (and Physcomitrella).

Lalonde, Sylvie; Frommer, Wolf B.

2012-01-01

198

The sucrose-trehalose 6-phosphate (Tre6P) nexus: specificity and mechanisms of sucrose signalling by Tre6P  

PubMed Central

Trehalose 6-phosphate (Tre6P), the intermediate of trehalose biosynthesis, has a profound influence on plant metabolism, growth, and development. It has been proposed that Tre6P acts as a signal of sugar availability and is possibly specific for sucrose status. Short-term sugar-feeding experiments were carried out with carbon-starved Arabidopsis thaliana seedlings grown in axenic shaking liquid cultures. Tre6P increased when seedlings were exogenously supplied with sucrose, or with hexoses that can be metabolized to sucrose, such as glucose and fructose. Conditional correlation analysis and inhibitor experiments indicated that the hexose-induced increase in Tre6P was an indirect response dependent on conversion of the hexose sugars to sucrose. Tre6P content was affected by changes in nitrogen status, but this response was also attributable to parallel changes in sucrose. The sucrose-induced rise in Tre6P was unaffected by cordycepin but almost completely blocked by cycloheximide, indicating that de novo protein synthesis is necessary for the response. There was a strong correlation between Tre6P and sucrose even in lines that constitutively express heterologous trehalose-phosphate synthase or trehalose-phosphate phosphatase, although the Tre6P:sucrose ratio was shifted higher or lower, respectively. It is proposed that the Tre6P:sucrose ratio is a critical parameter for the plant and forms part of a homeostatic mechanism to maintain sucrose levels within a range that is appropriate for the cell type and developmental stage of the plant.

Yadav, Umesh Prasad; Ivakov, Alexander; Feil, Regina; Lunn, John Edward

2014-01-01

199

Quantitative aerobic physiology of the yeast Dekkera bruxellensis, a major contaminant in bioethanol production plants.  

PubMed

Dekkera bruxellensis has been described as the major contaminant yeast of industrial ethanol production, although little is known about its physiology. The aim of this study was to investigate the growth of this yeast in diverse carbon sources and involved conducting shake-flask and glucose- or sucrose-limited chemostats experiments, and from the chemostat data, the stoichiometry of biomass formation during aerobic growth was established. As a result of the shake-flask experiments with hexoses or disaccharides, the specific growth rates were calculated, and a different behavior in rich and mineral medium was observed concerning to profile of acetate and ethanol production. In C-limited chemostats conditions, the metabolism of this yeast was completely respiratory, and the biomass yields reached values of 0.62 gDW gS(-1) . In addition, glucose pulses were applied to the glucose- or sucrose-limited chemostats. These results showed that D. bruxellensis has a short-term Crabtree effect. While the glucose pulse was at the sucrose-limited chemostat, sucrose accumulated at the reactor, indicating the presence of a glucose repression mechanism in D. bruxellensis. PMID:23078341

Leite, Fernanda Cristina Bezerra; Basso, Thiago Olitta; Pita, Will de Barros; Gombert, Andreas Karoly; Simões, Diogo Ardaillon; de Morais, Marcos Antonio

2013-02-01

200

Quantitative aerobic physiology of the yeast Dekkera bruxellensis, a major contaminant in bioethanol production plants.  

PubMed

Dekkera bruxellensis has been described as the major contaminant yeast of industrial ethanol production, although little is known about its physiology. The aim of this study was to investigate the growth of this yeast in diverse carbon sources and involved conducting shake flasks and glucose or sucrose-limited chemostats experiments, and from the chemostat data the stoichiometry of biomass formation during aerobic growth was established. As a result of the shake flask experiments with hexoses or disaccharides, the specific growth rates were calculated and a different behavior in rich and mineral medium was observed concerning to profile of acetate and ethanol production. In C-limited chemostats conditions, the metabolism of this yeast was completely respiratory and the biomass yields reached values of 0.62 gDW.gS(-1) . In addition, glucose pulses were applied to the glucose or sucrose-limited chemostats. These results showed that D. bruxellensis has a short-term Crabtree effect. While the glucose pulse was at the sucrose-limited chemostat, sucrose accumulated at the reactor, indicating the presence of a glucose repression mechanism in D. bruxellensis. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved. PMID:22998214

Leite, Fernanda Cristina Bezerra; Basso, Thiago Olitta; Pita, Will Barros; Gombert, Andreas Karoly; Simões, Diogo Ardaillon; de Morais Júnior, Marcos Antonio

2012-09-21

201

Comparison of ten media for the enumeration of yeasts in dairy products  

Microsoft Academic Search

Ten selective mycological media were evaluated for their suitability to enumerate yeasts in six different dairy products. Although variability was observed in counts obtained for individual dairy products, no significant overall differences (p > 0.05) were observed among the 10 selective plating media. Antibiotic-supplemented media such as oxytetracycline glucose yeast agar (OGY), yeast extract glucose chloramphenicol agar (YGC), rose bengal

J. J. Welthagen; B. C. Viljoen

1997-01-01

202

Long Distance Translocation of Sucrose, Serine, Leucine, Lysine, and Carbon Dioxide Assimilates  

PubMed Central

To determine the selectivity of movement of amino acids from source leaves to sink tissues in soybeans (Glycine max [L.] Merr. `Wells'), 14C-labeled serine, leucine, or lysine was applied to an abraded spot on a fully expanded trifoliolate leaflet, and an immature sink leaf three nodes above was monitored with a GM tube for arrival of radioactivity. Comparisons were made with 14C-sucrose and 14CO2 assimilates. Radioactivity was detected in the sink leaf for all compounds applied to the source leaflet. A heat girdle at the source leaf petiole essentially blocked movement of applied compounds, suggesting phloem transport. Transport velocities were similar (ranged from 0.75 to 1.06 cm/min), but mass transfer rates for sucrose were much higher than those for amino acids. Hence, the quantity of amino acids entering the phloem was much smaller than that of sucrose. Extraction of source, path, and sink tissues at the conclusion of the experiments revealed that 80 to 90% of the radioactivity remained in the source leaflet. Serine was partially metabolized in the transport path, whereas lysine and leucine were not. Although serine is found in greater quantities than leucine and lysine in the source leaf and path of soybeans, applied leucine and lysine were transported at comparable velocities and in only slightly lower quantities than was applied serine. Thus, no selective barrier against entry of these amino acids into the phloem exists.

Housley, Thomas L.; Peterson, David M.; Schrader, Larry E.

1977-01-01

203

Enzymatic-spectrophotometric determination of sucrose in coffee beans.  

PubMed

A spectrophotometric method for determining sucrose is proposed. Sucrose is hydrolyzed by invertase into glucose and fructose. Then, glucose is oxidized in presence of glucose oxidase and the produced hydrogen peroxide reacts with phenol-4-sulfonic acid sodium salt and 4-aminoantipyrine in presence of peroxidase, yielding a pink dye with an absorption maximum at 505 nm. This method was validated following the EURACHEM and VAM project guidelines for method validation. Trueness, precision, robustness, sensitivity and linearity were considered. The method was applied to the determination of sucrose in green and roasted coffee beans. A comparison with the HPLC method with pulsed amperometric detection was carried out. PMID:18970237

Alcázar, Angela; Jurado, J Marcos; Martín, M Jesús; Pablos, Fernando; González, A Gustavo

2005-10-15

204

Insulin acts at different CNS sites to decrease acute sucrose intake and sucrose self-administration in rats.  

PubMed

Findings from our laboratory and others have demonstrated that the hormone insulin has chronic effects within the CNS to regulate energy homeostasis and to decrease brain reward function. In this study, we compared the acute action of insulin to decrease intake of a palatable food in two different behavioral tasks-progressive ratios sucrose self-administration and micro opioid-stimulated sucrose feeding-when administered into several insulin-receptive sites of the CNS. We tested insulin efficacy within the medial hypothalamic arcuate (ARC) and paraventricular (PVN) nuclei, the nucleus accumbens, and the ventral tegmental area. Administration of insulin at a dose that has no chronic effect on body weight (5 mU) into the ARC significantly suppressed sucrose self-administration (75+/-5% of paired control). However, although the mu opioid DAMGO, [D-Ala2,N-MePhe4,Gly5-ol]-enkephalin acetate salt, stimulated sucrose intake at all four CNS sites, the ventral tegmental area was the only sensitive site for a direct effect of insulin to antagonize acute (60 min) micro opioid-stimulated sucrose feeding: sucrose intake was 53+/-8% of DAMGO-induced feeding, when insulin was coadministered with DAMGO. These findings demonstrate that free feeding of sucrose, and motivated work for sucrose, can be modulated within unique sites of the CNS reward circuitry. Further, they support the interpretation that adiposity signals, such as insulin, can decrease different aspects of ingestion of a palatable food, such as sucrose, in an anatomically specific manner. PMID:18525010

Figlewicz, Dianne P; Bennett, Jennifer L; Aliakbari, Sepideh; Zavosh, Aryana; Sipols, Alfred J

2008-08-01

205

Optimisation of methodology for enumeration of xerophilic yeasts from foods.  

PubMed

Xerophilic yeasts grow in intermediate moisture foods (aw, 0.65-0.85) such as sugar syrups, fruit concentrates, jams and brines. Non-osmophilic yeasts are enumerated by diluting in 0.1% peptone and then plated onto media such as malt extract or glucose yeast extract agar. In the presence of moulds the yeasts are enumerated in dichloran rose bengal chloramphenicol agar (DRBC). These procedures were demonstrated to be unsatisfactory for the enumeration of xerophilic yeasts in low aw foods. Investigations using pure cultures of xerophilic yeasts as well as naturally contaminated apple juice concentrates and glacé cherries have shown that a reduced aw diluent, in particular 30% w/w glycerol in combination with tryptone 10% glucose yeast extract agar (TGY) optimises the recovery of the yeasts, especially sublethally injured cells. The inclusion of sodium chloride in either the diluents or the culture media was not necessary to optimise the recovery of D. hansenii growing in 20% sodium chloride broths. PMID:9105918

Andrews, S; de Graaf, H; Stamation, H

1997-04-01

206

Sucrose metabolism: gateway to diverse carbon use and sugar signaling.  

PubMed

Sucrose metabolism plays pivotal roles in development, stress response, and yield formation, mainly by generating a range of sugars as metabolites to fuel growth and synthesize essential compounds (including protein, cellulose, and starch) and as signals to regulate expression of microRNAs, transcription factors, and other genes and for crosstalk with hormonal, oxidative, and defense signaling. This review aims to capture the most exciting developments in this area by evaluating (a) the roles of key sucrose metabolic enzymes in development, abiotic stress responses, and plant-microbe interactions; (b) the coupling between sucrose metabolism and sugar signaling from extra- to intracellular spaces; (c) the different mechanisms by which sucrose metabolic enzymes could perform their signaling roles; and (d) progress on engineering sugar metabolism and transport for high yield and disease resistance. Finally, the review outlines future directions for research on sugar metabolism and signaling to better understand and improve plant performance. PMID:24579990

Ruan, Yong-Ling

2014-04-29

207

Amide-linked N-methacryloyl sucrose containing polymers.  

PubMed

1',2,3,3',4,4',6-Hepta-O-benzyl-6'-N-methacryloyl-6'-deoxysucrose 1, 6'-deoxy-6'-N-methacryloyloxyethylureido sucrose 2 and 6,6'-dideoxy-6,6'-N-dimethacryloyloxyethylureido sucrose 3 have been homo-polymerized and copolymerized with styrene by a free radical process, yielding polymer materials with pendant sucrose moieties, attached to the polymer backbone via amide linkages. The results demonstrated that varying the structural features of the monomers, greatly affected the thermal and rheological properties of the polymers. The polymer materials obtained have been characterized by NMR, MALDI-TOF, DSC, AFM and EWC (equilibrium water content). The efficient synthesis of the three novel, regioisomerically pure, N-methacryloylamide sucrose-containing monomers (1, 2 and 3) have been described. PMID:24906726

Petrova, Krasimira T; Potewar, Taterao M; Ascenso, Osvaldo S; Barros, M Teresa

2014-09-22

208

Aqueous batch rebinding and selectivity studies on sucrose imprinted polymers.  

PubMed

Polymers imprinted with sucrose and corresponding non-imprinted polymers are prepared photo-chemically at 3 degrees C and thermally at 65 degrees C. The pre-polymerization complex formation in dimethyl sulfoxide between sucrose and methacrylic acid via hydrogen bonding was investigated through (1)H NMR titration. The imprinting effect and the selectivity of the imprinted polymers in water are studied by batch rebinding studies with different mono and disaccharides and fitted to the Freundlich isotherm. Based on the calculated numbers of binding sites and average affinity, it is concluded that sucrose has been successfully imprinted at 3 and 65 degrees C. The polymer imprinted at 3 degrees C possesses the best recognition properties. The imprinted polymers are selective towards sucrose in water. PMID:19223166

Kirk, Camilla; Jensen, Martin; Kjaer, Christina N; Smedskjaer, Morten M; Larsen, Kim Lambertsen; Wimmer, Reinhard; Yu, Donghong

2009-11-15

209

Sucrose Hydrolysis-Temperature Dependence of the Activation Energy.  

National Technical Information Service (NTIS)

Sucrose hydrolysis is often cited as one of the classic examples of a chemical reaction with a temperature-dependent aactivation enery. Two different investigators, Moelwyn-Hughes (polarimetry) and Leininger and Kilpatrick (dilatometry), both claimed that...

J. R. Ward

1985-01-01

210

Aqueous batch rebinding and selectivity studies on sucrose imprinted polymers  

Microsoft Academic Search

Polymers imprinted with sucrose and corresponding non-imprinted polymers are prepared photo-chemically at 3°C and thermally at 65°C. The pre-polymerization complex formation in dimethyl sulfoxide between sucrose and methacrylic acid via hydrogen bonding was investigated through 1H NMR titration. The imprinting effect and the selectivity of the imprinted polymers in water are studied by batch rebinding studies with different mono and

Camilla Kirk; Martin Jensen; Christina N. Kjaer; Morten M. Smedskjaer; Kim Lambertsen Larsen; Reinhard Wimmer; Donghong Yu

2009-01-01

211

Production of 1-kestose in transgenic yeast expressing a fructosyltransferase from Aspergillus foetidus.  

PubMed

Sucrose-inducible secretory sucrose:sucrose 1-fructosyltransferase (1-SST) from Aspergillus foetidus has been purified and subjected to N-terminal amino acid sequence determination. The enzyme is extensively glycosylated, and the active form is probably represented by a dimer of identical subunits with an apparent molecular mass of 180 kDa as judged from mobility in seminative acrylamide gels. The enzyme catalyzes fructosyl transfer from sucrose to sucrose producing glucose and 1-kestose. Oligosaccharides with a higher degree of polymerization are not obtained with sucrose as the substrate. The cDNA encoding the A. foetidus 1-SST has been cloned and sequenced. Sequence homology was found to be highest to levanases, but no hydrolytic activity was observed when levan was incubated with the enzyme. Expression of the cloned gene in an invertase-deficient mutant of Saccharomyces cerevisiae resulted in 1-kestose production, with 6-kestose and neokestose being side products of the reaction. Products were well distinguishable from those formed by yeast transformants expressing a cytosolic invertase. PMID:9495772

Rehm, J; Willmitzer, L; Heyer, A G

1998-03-01

212

ESR investigation of sucrose radicals produced by particle irradiation  

NASA Astrophysics Data System (ADS)

We investigated sucrose radicals produced by heavy-ion irradiation with various linear energy transfer (LETs) and the possibility for a sucrose electron spin resonance (ESR) dosimeter. The impact of heavy ions on sucrose produced sucrose radicals, which were measured by ESR. The obtained spectral pattern was the same as that for helium (He) ions, carbon (C) ions, neon (Ne) ions, iron (Fe) ions, and ?-ray irradiation. Identical spectra were measured after 1 year, but the initial intensities decreased by a few percent when the samples were kept in ESR tubes with the caps at ambient temperature. The total spin concentration obtained by heavy-ion irradiation had a linear relation with the absorbed dose, and correlated logarithmically with the LET. Qualitative ESR analyses showed that the production of sucrose radicals depended on both the particle identity and the LET at the same dose. The production of spin concentration by He ions was the most sensitive to LET. Empirical relations between the LET and the spin yield for various particles imply that the LET at a certain dose can be estimated by the spin concentration. Therefore, the present ESR results imply that sucrose can be used to monitor the absorbed dose and the LET of particle irradiation.

Nakagawa, Kouichi; Sato, Yukio

2004-05-01

213

Astaxanthinogenesis in the yeast Phaffia rhodozyma : optimization of low-cost culture media and yeast cell-wall lysis.  

PubMed

Astaxanthin is a diketo-dihydroxy-carotenoid produced by Phaffia rhodozyma, a basidiomicetous yeast. A low-cost fermentation medium consisting of raw sugarcane juice and urea was developed to exploit the active sucrolytic/urelolytic enzyme apparatus inherent to the yeast. As compared to the beneficial effect of 0.1 g% urea, a ready nitrogen source, mild phosphoric pre inversion of juice sucrose to glucose and fructose, promptly fermentable carbon sources, resulted in smaller benefits. Corn steep liquor (CSL) was found to be a valuable supplement for both yeast biomass yield (9.2 g dry cells/L) and astaxanthin production (1.3 mg/g cells). Distillery effluent (vinace), despite only a slightly positive effect on yeast growth, allowed for the highest pigment productivity (1.9 mg/g cells). Trace amounts of Ni2 (1 mg/L, as a cofactor for urease) resulted in controversial effects, namely, biomass decrease and astaxanthin increase, with no effect on the release (and uptake) of ammonium ion from urea. Since the synthesized astaxanthin is associated with the yeast cell and the pigment requires facilitated release for aquaculture uses (farmed fish meat staining), an investigation of the yeast cell wall was undertaken using detergent-treated cells. The composition of the rigid yeast envelope was found to be heterogeneous. Its partial acid or enzymatic depolymerization revealed glucose and xylose as common monomeric units of the cell-wall glycopolymers. Yeast cell-wall partial depolymerization with appropriate hydrolases may improve the pigment bioavailability for captive aquatic species and poultry. PMID:18576089

Fontana, J D; Chocial, M B; Baron, M; Guimaraes, M F; Maraschin, M; Ulhoa, C; Florêncio, J A; Bonfim, T M

1997-01-01

214

Heterologous Protein Secretion from Yeast  

Microsoft Academic Search

Secretion of calf prochymosin from yeast yields fully activable zymogen while production in the yeast cytoplasm yields insoluble, unactivable enzyme with aberrant disulfide bonding. Factors that increase the efficiency of secretion of prochymosin from yeast are use of a yeast secretion signal sequence, integration of the transcriptional unit into the yeast genome, and specific mutations in a number of host

Robert A. Smith; Margaret J. Duncan; Donald T. Moir

1985-01-01

215

Effect of Dietary Sucrose in Humans on Blood Uric Acid, Phosphorus, Fructose, and Lactic Acid Responses to a Sucrose Load  

Microsoft Academic Search

10 men and 9 women consumed diets that were identical, except for the 30% of the calories derived from either starch or sucrose, for 6 weeks in a crossover design. Of the total calories, 10% were given at breakfast and 90% at dinner. A sucrose load of 2 g\\/kg body weight was administered 1 week before and during the last

Joy T. Solyst; Orho E. Michaelis; IV; Sheldon Reiser; Kathleen C. Ellwood; Elizabeth S. Prather

1980-01-01

216

Population Growth in Yeasts  

NSDL National Science Digital Library

This lesson is the second of two that explore cellular respiration and population growth in yeasts. In the first lesson, students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Based on questions that arose during the first lesson and its associated activity, in this lesson students work in small groups to design experiments that will determine how environmental factors affect yeast population growth.

Engineering K-Ph.d. Program

217

Mitochondrial metabolism and stress response of yeast: Applications in fermentation technologies.  

PubMed

Mitochondria are sites of oxidative respiration. During sake brewing, sake yeasts are exposed to long periods of hypoxia; the structure, role, and metabolism of mitochondria of sake yeasts have not been studied in detail. It was first elucidated that the mitochondrial structure of sake yeast transforms from filamentous to dotted structure during sake brewing, which affects malate metabolism. Based on the information of yeast mitochondria during sake brewing, practical technologies have been developed; (i) breeding pyruvate-underproducing sake yeast by the isolation of a mutant resistant to an inhibitor of mitochondrial pyruvate transport; and (ii) modifying malate and succinate production by manipulating mitochondrial activity. During the bread-making process, baker's yeast cells are exposed to a variety of baking-associated stresses, such as freeze-thaw, air-drying, and high sucrose concentrations. These treatments induce oxidative stress generating reactive oxygen species due to mitochondrial damage. A novel metabolism of proline and arginine catalyzed by N-acetyltransferase Mpr1 in the mitochondria eventually leads to synthesis of nitric oxide, which confers oxidative stress tolerance on yeast cells. The enhancement of proline and arginine metabolism could be promising for breeding novel baker's yeast strains that are tolerant to multiple baking-associated stresses. These new and practical methods provide approaches to improve the processes in the field of industrial fermentation technologies. PMID:24210052

Kitagaki, Hiroshi; Takagi, Hiroshi

2014-04-01

218

Moonlighting Proteins in Yeasts  

PubMed Central

Proteins able to participate in unrelated biological processes have been grouped under the generic name of moonlighting proteins. Work with different yeast species has uncovered a great number of moonlighting proteins and shown their importance for adequate functioning of the yeast cell. Moonlighting activities in yeasts include such diverse functions as control of gene expression, organelle assembly, and modification of the activity of metabolic pathways. In this review, we consider several well-studied moonlighting proteins in different yeast species, paying attention to the experimental approaches used to identify them and the evidence that supports their participation in the unexpected function. Usually, moonlighting activities have been uncovered unexpectedly, and up to now, no satisfactory way to predict moonlighting activities has been found. Among the well-characterized moonlighting proteins in yeasts, enzymes from the glycolytic pathway appear to be prominent. For some cases, it is shown that despite close phylogenetic relationships, moonlighting activities are not necessarily conserved among yeast species. Organisms may utilize moonlighting to add a new layer of regulation to conventional regulatory networks. The existence of this type of proteins in yeasts should be taken into account when designing mutant screens or in attempts to model or modify yeast metabolism.

Gancedo, Carlos; Flores, Carmen-Lisset

2008-01-01

219

Production of Extracellular and Total Invertase by Candida utilis, Saccharomyces cerevisiae, and Other Yeasts  

PubMed Central

Some strains of Candida utilis produce exceptionally large amounts of extracellular and total invertase. Strain Y-900 of C. utilis produces high yields whether the carbon source is sucrose, glucose, maltose, or xylose and still higher yields with lactic acid, glycerol, and ethyl alcohol. Approximately 20 to 30% of the total invertase of C. utilis is extracellular. Strains of Saccharomyces cerevisiae and Saccharomyces carlsbergensis are generally inferior to C. utilis in production of extracellular and total invertase, the difference being accentuated in shaken cultures. The industrial yeasts are generally superior in invertase production to the other yeasts included in the survey.

Dworschack, Robert G.; Wickerham, Lynferd J.

1961-01-01

220

Improved salt tolerance of transgenic tobacco expressing apoplastic yeast-derived invertase.  

PubMed

We investigated the salt tolerance of transgenic tobacco, in which yeast invertase is expressed in the apoplastic (Apo-Inv) spaces. Whereas photosynthetic activities in wild-type tobacco in light were inhibited under salt stress, transgenic Apo-Inv tobacco maintained constant photosynthetic activities. The physical appearance of plants under salt stress also indicates that yeast invertase expression in the apoplastic space is beneficial for inducing salt tolerance. Apo-Inv tobacco had a much higher osmotic pressure increase in the cell sap than did wild-type tobacco under this type of stress. The physiological importance of sucrose metabolism under salt stress is discussed. PMID:11230581

Fukushima, E; Arata, Y; Endo, T; Sonnewald, U; Sato, F

2001-02-01

221

Microbial water relations: features of the intracellular composition of sugar-tolerant yeasts.  

PubMed

Several factors contributed to differences in intracellular composition between sugar-tolerant (osmophilic) and nontolerant species of yeast. One such factor was the difference in accumulation of those nonelectrolytes whose uptake was not dominated by vigorous metabolism. In such cases (lactose and glycerol), the sugar-tolerant species had a much lower capacity for the solute than did the nontolerant species. Sucrose uptake was consistently different between all sugar-tolerant strains on the one hand and all nontolerant strains on the other. The difference was attributable in part to metabolism of sucrose by the nontolerant yeasts. The major difference between the two types of yeast, however, was the presence of one or more polyhydric alcohols at high concentrations within each of the sugar-tolerant strains but none of the nontolerant strains. In most cases the major polyol was arabitol. The solute concentration (and, hence, water availability) of the growth medium affected both the amount of arabitol produced by Saccharomyces rouxii and the proportion retained by the yeast after brief washing with water at 0 C. When the yeast was suspended in a buffer at 30 C, the polyol leaked out at a slow, constant, reproducible rate. The polyene antibiotic amphotericin B caused rapid release of polyol by the yeast, the rate being proportional to amphotericin concentration. Contact of the yeast with glucose (1 mM) caused an extremely rapid ejection of polyol which lasted less than 40 s. Some implications of these results are discussed, as is the role of the polyol as a compatible solute in determining the water relations of the yeast. PMID:4598001

Brown, A D

1974-06-01

222

Multimembrane bioreactor for extractive fermentation  

SciTech Connect

A multimembrane reactor is described. Four layers (gas, cells, nutrient, and solvent) are separated by membranes. This structure prevents solvent emulsification in the fermentation broth. The system was tested for ethyl alcohol production from glucose using yeast. Tributyl phosphate (TBP) was chosen as the extractant. Experiments demonstrate for the first time a successful extractive fermentation with a practical solvent. Prevention of emulsification removes the toxic effect of TBP on yeast metabolism. (Refs. 29).

Cho, T.; Shuler, M.L.

1986-03-01

223

The Mode of Sucrose Degradation in Potato Tubers Determines the Fate of Assimilate Utilization  

PubMed Central

Cytosolic (U-IN-2) or apoplasmic (U-IN-1) targeting of yeast invertase in potato tubers leads to a reduction in sucrose and an increase in glucose content, but specific phenotypical changes are dependent on the subcellular targeting of the enzyme. Cytosolic expression leads to a more severe phenotype with the most striking aspects being reduced starch content and increased respiration. Despite extensive research, the regulatory mechanisms leading to these changes remain obscure. Recent technological advancements regarding potato transcriptional and genomic research presented us with the opportunity to revisit these lines and perform detailed gene expression analysis, in combination with extensive metabolic profiling, to identify regulatory networks underlying the observed changes. Our results indicate that in both genotypes reduced UDP-glucose production is associated with a reduced expression of cell wall biosynthetic genes. In addition, U-IN-1 tubers are characterized by elevated expression of senescence-associated genes, coupled to reduced expression of genes related to photosynthesis and the cytoskeleton. We provide evidence that increased respiration, observed specifically in U-IN-2 tubers, might be due to sugar signaling via released trehalose-6-phosphate inhibition of the SnRK1 complex. In both genotypes, expression of the plastidic glucose-6-phosphate transporter (GPT) is significantly down-regulated. This leads to a shift in the cytosolic to plastidic glucose-6-phosphate ratio and hence might limit starch synthesis but also the oxidative pentose phosphate pathway. This might explain the observed changes in several additional plastid localized pathways, most notably reduced expression of fatty acid biosynthetic genes and an accumulation of shikimate. Interestingly, a strict negative correlation between invertase and GPT expression could be observed in a wide range of potato tubers. This reciprocal regulation may be part of a more general switch controlling energy versus storage metabolism, suggesting that the fate of assimilate utilization is coordinated at the level of sucrose degradation.

Ferreira, Stephanus J.; Sonnewald, Uwe

2012-01-01

224

PFGSE-NMR study of the self-diffusion of sucrose fatty acid monoesters in water.  

PubMed

The micellization of pure monosubstituted sucrose fatty acid esters in water, namely sucrose octanoate, sucrose decanoate, sucrose laurate, sucrose dodec-5-cis-enoate, sucrose myristate, and sucrose palmitate, has been investigated by means of two NMR methods, pulsed field gradient spin-echo NMR (PFGSE-NMR), giving access to the self-diffusion coefficients of free molecules and micelles in solution, and the ERETIC method (electronic reference to access in vivo concentrations) for the measurement of concentrations by external calibration of a synthetic NMR signal. The early micellar regions and, when possible, the premicellar regions were investigated. By this method, we obtained the hydrodynamic radii of micelles, displaying a linear progression in relation to the chain length and an accurate determination of critical micellar concentration (CMC) for each sucrose ester. The effect of the regiochemistry of fatty chain grafting has been investigated, showing special behavior for 1'-O-sucrose palmitate. PMID:15848439

Molinier, Valérie; Fenet, Bernard; Fitremann, Juliette; Bouchu, Alain; Queneau, Yves

2005-06-01

225

Method for converting sucrose to .beta.-D-glucose  

DOEpatents

Disclosed is an apparatus and method for continuously converting sucrose to .beta.-D-glucose. The method comprises a three-stage enzymatic reactor in which an aqueous solution of sucrose is first converted into a solution of fructose and .alpha.-D-glucose by passing it through a porous, packed column containing an inert media on which invertase is immobilized. This solution is then sent through a second packed column containing glucose isomerase and finally a third packed column containing mutarotase. Solution temperature and pH are adjusted to maximize glucose output.

Simmons, Blake A. (San Francisco, CA); Volponi, Joanne V. (Livermore, CA); Ingersoll, David (Albuquerque, NM); Walker, Andrew (Woodinville, WA)

2009-07-07

226

Hospitalized infants who hurt: a sweet solution with oral sucrose.  

PubMed

Pain is harmful to newborn infants. Oral sucrose is safe, inexpensive, and effective at preventing and reducing pain in hospitalized babies who undergo invasive procedures. The sugar can be used alone or in combination with analgesics and other nonpharmacological interventions to provide analgesia. Parents expect nurses to serve as pain advocates for the parents' newborns and to protect the babies from needless suffering. It is incumbent upon nurses to stay abreast of the current evidence and integrate use of oral sucrose into daily pain management practice in emergency, acute, and critical care units. PMID:22298719

Pasek, Tracy Ann; Huber, Jessica Marie

2012-02-01

227

Avocado Oil Supplementation Modifies Cardiovascular Risk Profile Markers in a Rat Model of Sucrose-Induced Metabolic Changes  

PubMed Central

The purpose of this study was to evaluate the effects of avocado oil administration on biochemical markers of cardiovascular risk profile in rats with metabolic changes induced by sucrose ingestion. Twenty-five rats were divided into five groups: a control group (CG; basic diet), a sick group (MC; basic diet plus 30% sucrose solution), and three other groups (MCao, MCac, and MCas; basic diet plus 30% sucrose solution plus olive oil and avocado oil extracted by centrifugation or using solvent, resp.). Glucose, total cholesterol, triglycerides, phospholipids, low- and high-density lipoproteins (LDL, HDL), very low-density lipoprotein (VLDL), lactic dehydrogenase, creatine kinase, and high sensitivity C-reactive protein concentration were analyzed. Avocado oil reduces TG, VLDL, and LDL levels, in the LDL case significantly so, without affecting HDL levels. An effect was exhibited by avocado oil similar to olive oil, with no significant difference between avocado oil extracted either by centrifugation or solvent in myocardial injury biochemical indicators. Avocado oil decreased hs-CRP levels, indicating that inflammatory processes were partially reversed. These findings suggested that avocado oil supplementation has a positive health outcome because it reduces inflammatory events and produces positive changes in the biochemical indicators studied, related to the development of metabolic syndrome.

Carvajal-Zarrabal, Octavio; Nolasco-Hipolito, Cirilo; Aguilar-Uscanga, M. Guadalupe; Melo-Santiesteban, Guadalupe; Hayward-Jones, Patricia M.; Barradas-Dermitz, Dulce M.

2014-01-01

228

Avocado oil supplementation modifies cardiovascular risk profile markers in a rat model of sucrose-induced metabolic changes.  

PubMed

The purpose of this study was to evaluate the effects of avocado oil administration on biochemical markers of cardiovascular risk profile in rats with metabolic changes induced by sucrose ingestion. Twenty-five rats were divided into five groups: a control group (CG; basic diet), a sick group (MC; basic diet plus 30% sucrose solution), and three other groups (MCao, MCac, and MCas; basic diet plus 30% sucrose solution plus olive oil and avocado oil extracted by centrifugation or using solvent, resp.). Glucose, total cholesterol, triglycerides, phospholipids, low- and high-density lipoproteins (LDL, HDL), very low-density lipoprotein (VLDL), lactic dehydrogenase, creatine kinase, and high sensitivity C-reactive protein concentration were analyzed. Avocado oil reduces TG, VLDL, and LDL levels, in the LDL case significantly so, without affecting HDL levels. An effect was exhibited by avocado oil similar to olive oil, with no significant difference between avocado oil extracted either by centrifugation or solvent in myocardial injury biochemical indicators. Avocado oil decreased hs-CRP levels, indicating that inflammatory processes were partially reversed. These findings suggested that avocado oil supplementation has a positive health outcome because it reduces inflammatory events and produces positive changes in the biochemical indicators studied, related to the development of metabolic syndrome. PMID:24719499

Carvajal-Zarrabal, Octavio; Nolasco-Hipolito, Cirilo; Aguilar-Uscanga, M Guadalupe; Melo-Santiesteban, Guadalupe; Hayward-Jones, Patricia M; Barradas-Dermitz, Dulce M

2014-01-01

229

Antisense inhibition of tomato fruit sucrose synthase decreases fruit setting and the sucrose unloading capacity of young fruit.  

PubMed Central

The role of sucrose synthase (SuSy) in tomato fruit was studied in transgenic tomato (Lycopersicon esculentum) plants expressing an antisense fragment of fruit-specific SuSy RNA (TOMSSF) under the control of the cauliflower mosaic virus 35S promoter. Constitutive expression of the antisense RNA markedly inhibited SuSy activity in flowers and fruit pericarp tissues. However, inhibition was only slight in the endosperm and was undetectable in the embryo, shoot, petiole, and leaf tissues. The activity of sucrose phosphate synthase decreased in parallel with that of SuSy, but acid invertase activity did not increase in response to the reduced SuSy activity. The only effect on the carbohydrate content of young fruit was a slight reduction in starch accumulation. The in vitro sucrose import capacity of fruits was not reduced by SuSy inhibition at 23 days after anthesis, and the rate of starch synthesized from the imported sucrose was not lessened even when SuSy activity was decreased by 98%. However, the sucrose unloading capacity of 7-day-old fruit was substantially decreased in lines with low SuSy activity. In addition, the SuSy antisense fruit from the first week of flowering had a slower growth rate. A reduced fruit set, leading to markedly less fruit per plant at maturity, was observed for the plants with the least SuSy activity. These results suggest that SuSy participates in the control of sucrose import capacity of young tomato fruit, which is a determinant for fruit set and development.

D'Aoust, M A; Yelle, S; Nguyen-Quoc, B

1999-01-01

230

No evidence for the occurrence of substrate inhibition of Arabidopsis thaliana sucrose synthase-1 (AtSUS1) by fructose and UDP-glucose  

PubMed Central

Sucrose synthase (SuSy) catalyzes the reversible conversion of sucrose and NDP into the corresponding nucleotide-sugars and fructose. The Arabidopsis genome possesses six SUS genes (AtSUS1–6) that code for proteins with SuSy activity. As a first step to investigate optimum fructose and UDP-glucose (UDPG) concentrations necessary to measure maximum sucrose-producing SuSy activity in crude extracts of Arabidopsis, in this work we performed kinetic analyses of recombinant AtSUS1 in two steps: (1) SuSy reaction at pH 7.5, and (2) chromatographic measurement of sucrose produced in step 1. These analyses revealed a typical Michaelis-Menten behavior with respect to both UDPG and fructose, with Km values of 50 ?M and 25 mM, respectively. Unlike earlier studies showing the occurrence of substrate inhibition of UDP-producing AtSUS1 by fructose and UDP-glucose, these analyses also revealed no substrate inhibition of AtSUS1 at any UDPG and fructose concentration. By including 200 mM fructose and 1 mM UDPG in the SuSy reaction assay mixture, we found that sucrose-producing SuSy activity in leaves and stems of Arabidopsis were exceedingly higher than previously reported activities. Furthermore, we found that SuSy activities in organs of the sus1/sus2/sus3/sus4 mutant were ca. 80–90% of those found in WT plants.

Almagro, Goizeder; Baroja-Fernandez, Edurne; Munoz, Francisco Jose; Bahaji, Abdellatif; Etxeberria, Ed; Li, Jun; Montero, Manuel; Hidalgo, Maite; Sesma, Maria Teresa; Pozueta-Romero, Javier

2012-01-01

231

Phosphoenolpyruvate-dependent sucrose phosphotransferase activity in Streptococcus mutans NCTC 10449.  

PubMed Central

A phosphoenolpyruvate-dependent sucrose phosphotransferase system (PTS) has been demonstrated, by an enzyme-coupled reaction and product isolation, in decryptified cell suspensions of the cariogenic microorganism Streptococcus mutans NCTC 10449. The apparent sucrose PTS reaction for sucrose-adapted, sucrose-challenged cells displayed saturation kinetics with an apparent Km of 7.14 x 10(-5) M, which was distinct from the Km of the glucose PTS activity of glucose-adapted, glucose-challenged cells. Both the sucrose and the glucose PTS activities appear to be inducible and under separate genetic control. The sucrose PTS reaction demonstrated in decryptified cells had an absolute requirement for phosphoenolpyruvate. Only 2-phosphoglycerate, the immediate glycolytic precursor of phosphoenolpyruvate, was found to substitute for phosphoenolpyruvate in this reaction in the absence of fluoride. The sucrose PTS activity of sucrose-adapted cells was competitively inhibited by raffinose and lactose; these same sugars had no effect on the apparent glucose PTS activity. Fructose was the only carbohydrate tested other than sucrose which elicited an apparent PTS reaction in sucrose-adapted cells. The product of the sucrose PTS reaction was isolated and behaved chromatographically on a Dowex-1-X8 column like a monophosphate ester. Alkaline phosphatase treatment of the presumptive sucrose monophosphate liberated a component which behaved chromatographically like free sucrose. Subsequent acid hydrolysis of this component produced moieties which behaved chromatographically like glucose and fructose.

Slee, A M; Tanzer, J M

1979-01-01

232

Application of high performance anion exchange chromatography to study invertase-catalysed hydrolysis of sucrose and formation of intermediate fructan products.  

PubMed

Baker's yeast invertase was found to catalyse transfructosylation reactions in aqueous and anhydrous organic media with sucrose as a substrate, leading to the formation of five intermediate fructans in addition to the release of D-glucose (D-Glc)and D-fructose (D-Fru). All the reaction products were separated and quantitatively estimated using high performance anion exchange-pulsed amperometric detection equipment. The unknown products were subsequently identified by linkage analysis as beta-D-Fru-(2 --> 1)-beta-D-Fru-(2 --> 1)- alpha-D-glucopyranoside (1-kestose), beta-D-Fru- (2 --> 6)-alpha-D-glucopyranoside (6-beta-fructofuranosylglucose), beta-D-Fru-(2 -->1) -beta-D-fructofuranoside (inulobiose), beta-D-Fru-(2 --> 6)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (6-kestose) and beta-D-Fru-(2 --> 6)-alpha-D-Glc-(1 --> 2)-beta-D-fructofuranoside (neokestose); and this last was eluted together with a disaccharide. The time-course of sucrose hydrolysis via fructan production in 2 ml of a 50 mM sodium acetate buffer (pH 4.5) containing 0.2 M sucrose and 25 U of invertase was different from that in 2 ml of anhydrous toluene with 1.46 M sucrose and 1,000 U of invertase as a suspended powder. Under the latter experimental conditions, invertase was found to exhibit cyclic behaviour, where sucrose was degraded and subsequently synthesised. This observation has not yet been reported, as far as we know. PMID:11234959

Farine, S; Versluis, C; Bonnici, P J; Heck, A; L'homme, C; Puigserver, A; Biagini, A

2001-01-01

233

Yeast Biomass Production in Brewery's Spent Grains Hemicellulosic Hydrolyzate  

NASA Astrophysics Data System (ADS)

Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery's spent grains hemicellulosic hydrolyzate supplemented with mineral nutrients. The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h-1, 0.61 g g-1, and 0.56 g 1-1 h-1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of some essential amino acids and a high ratio of unsaturated over saturated fatty acids.

Duarte, Luís C.; Carvalheiro, Florbela; Lopes, Sónia; Neves, Ines; Gírio, Francisco M.

234

Construction of a flocculating yeast for fructose production from inulin  

Microsoft Academic Search

Construction of flocculating yeast lacking for fructose utilisation was realised by integration of the FLO1 flocculation gene in the ribosomal DNA of an hexokinase deficient (hxk1, hxk2) Saccharomyces cerevisiae strain (ATCC36859). Simultaneous production of ethanol and fructose was obtained from glucose\\/fructose mixtures or from hydrolysed Jerusalem artichoke extracts using the transformed yeast in batch fermentations and in a continuous reactor

F. Remize; S. Schorr-Galindo; J. P. Giraud; S. Dequin; B. Blondin

1998-01-01

235

Hydrolysis of grape glycosides by enological yeast ?-glucosidases  

Microsoft Academic Search

Three enological yeast strains, belonging to the speciesDebaryomyces hansenii, Debaryomyces polymorphus, andSaccharomyces cerevisiae, characterized by an exocellular ?-glucosidase activity, were examined for their ability to hydrolize a glycosidic extract from grape juice. The enzymatic preparations (culture supernant fluid) of the different yeasts released different amounts of terpenols such as linalol, ?-terpineol, geraniol, nerol, citronellol and benzyl and 2-phenylethyl alcohol. The

I. Rosi; P. Domizio; M. Vinella; M. Salicone

1995-01-01

236

THE INFLUENCE OF DEXTRIN AND SUCROSE ON GROWTH AND DERMATITIS  

Microsoft Academic Search

In the study of the water-soluble vitamins of the B-complex the carbohydrate constituent of the basal ration appears to be a factor influencing both the incidence of dermatitis and rate of growth. The observations of Hogan and Richardson ( '32 and '34), who report a high incidence of dermatitis in rats when using sucrose, and the more recent studies by

B. C. BENDER; G. E. FLANIGAN; G. C. SUPPLEE

237

Microdetermination of Sucrose in Plasma with the Anthrone Reagent.  

National Technical Information Service (NTIS)

Quantitative determinations of sucrose in plasma required preliminary protein precipitation with Ba(OH)2 - ZnSO4 or ethyl alcohol followed by centrifugation. Aliquots of the resultant protein-free supernate were then concentrated to dryness at 80 C with a...

J. P. Hannon

1979-01-01

238

Formation of levan and sorbitol from sucrose by Zymomonas mobilis  

Microsoft Academic Search

Ethanol yields produced by Zymomonas strains from sucrose are significantly lower than from glucose or fructose. The low yield is a consequence of the formation of both levan and sorbitol as by-products. Most of the levan is in a non-precipitable form, indicating low molecular weight. Formation of sorbitol was observed with both the Zymomonas strains studied. The measured amounts of

Liisa Viikari

1984-01-01

239

Sucrose Responsiveness, Learning Success, and Task Specialization in Ants  

ERIC Educational Resources Information Center

Social insects possess remarkable learning capabilities, which are crucial for their ecological success. They also exhibit interindividual differences in responsiveness to environmental stimuli, which underlie task specialization and division of labor. Here we investigated for the first time the relationships between sucrose responsiveness,…

Perez, Margot; Rolland, Uther; Giurfa,, Martin; d'Ettorre, Patrizia

2013-01-01

240

Aging and Information Seeking: Patterns in Sampling of Sucrose Solutions.  

ERIC Educational Resources Information Center

Explored age-related strategies of information seeking and decision making. Young and old female participants (N=38) engaged in detecting the presence of sucrose in solutions of various concentrations. Compared to young people, the aged sampled more and had a higher detection threshold, indicating higher requirements for information. (BH)

Shapira, N.; Kushnir, T.

1985-01-01

241

Breaking the intergeneric crossing barrier in papaya using sucrose treatment  

Microsoft Academic Search

A breeding programme was undertaken using Carica papaya var. Surya and Vasconcellea cauliflora with a view to raise progenies resistant to ‘papaya ringspot virus’ (PRSV). Earlier studies have clearly demonstrated the cross incompatibility between these two genera. Hence, an attempt was made to break this barrier using sucrose. The pollen of V. cauliflora was collected and pollination was carried out

M. R. Dinesh; A. Rekha; K. V. Ravishankar; K. S. Praveen; L. C. Santosh

2007-01-01

242

Efflux of sucrose from minor veins of tobacco leaves  

Microsoft Academic Search

Mature leaves import limited amounts of nutrient when darkened for prolonged periods. We tested the hypothesis that import is restricted by the apoplast-phloem loading mechanism, ie., as sucrose exits the phloem of minor veins it is retrieved by the same tissue, thus depriving the mesophyll of nutrient. When single, attached, mature leaves of tobacco (Nicotiana tabacum L.) plants were darkened,

Robert Turgeon

1984-01-01

243

Astaxanthinogenesis in the yeast Phaffia rhodozyma - optimization of low-cost culture media and yeast cell-wall lysis  

SciTech Connect

Astaxanthin is a diketo-dihydroxy-carotenoid produced by Phaffia rhodozyma, a basidiomicetous yeast. A low-cost fermentation medium consisting of raw sugarcane juice and urea was developed to exploit the active sucrolytic/urelolytic enzyme apparatus inherent to the yeast. As compared to the beneficial effect of 0.1 g% urea, a ready nitrogen source, mild phosphoric pre inversion of juice sucrose to glucose and fructose, promptly fermentable carbon sources, resulted in smaller benefits. Corn steep liquor (CSL) was found to be a valuable supplement for both yeast biomass yield (9.2 g dry cells/L) and astaxanthin production (1.3 mg/g cells). Distillery effluent (vinace), despite only a slightly positive effect on yeast growth, allowed for the highest pigment productivity (1.9 mg/g cells). Trace amounts of Ni{sup 2} (1 mg/L, as a cofactor for urease) resulted in controversial effects, namely, biomass decrease and astaxanthin increase, with no effect on the release (and uptake) of ammonium ion from urea. 13 refs., 6 figs.

Fontana, J.D.; Baron, M.; Guimaraes, M.F. [LQBB-Biomass Chemo Biotechnology Lab., Curitiba (Brazil)] [and others

1997-12-31

244

RNAi in budding yeast  

PubMed Central

RNAi, a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast, Saccharomyces cerevisiae. Here, we show that RNAi is present in other budding-yeast species, including Saccharomyces castellii and Candida albicans. These species use noncanonical Dicer proteins to generate siRNAs, which mostly correspond to transposable elements and Y’ subtelomeric repeats. In S. castellii, RNAi mutants are viable but have excess Y’ mRNA levels. In S. cerevisiae, introducing Dicer and Argonaute of S. castellii restores RNAi, and the reconstituted pathway silences endogenous retrotransposons. These results identify a novel class of Dicer proteins, bring the tool of RNAi to the study of budding yeasts, and bring the tools of budding yeast to the study of RNAi.

Mower, Jeffrey P.; Wolfe, Kenneth H.; Fink, Gerald R.; Bartel, David P.

2013-01-01

245

Soybean ENOD40 encodes two peptides that bind to sucrose synthase  

PubMed Central

ENOD40 is expressed at an early stage in root nodule organogenesis in legumes. Identification of ENOD40 homologs in nonleguminous plants suggests that this gene may have a more general biological function. In vitro translation of soybean ENOD40 mRNA in wheat germ extracts revealed that the conserved nucleotide sequence at the 5? end (region I) encodes two peptides of 12 and 24 aa residues (peptides A and B). These peptides are synthesized de novo from very short, overlapping ORFs. Appropriate ORFs are present in all legume ENOD40s studied thus far. In this case small peptides are directly translated from polycistronic eukaryotic mRNA. The 24-aa peptide B was detected in nodules by Western blotting. Both peptides specifically bind to the same 93-kDa protein, which was affinity purified from soybean nodules. Using peptide mass fingerprinting, we identified this binding protein as nodulin 100, which is a subunit of sucrose synthase. Based on our data we suggest that ENOD40 peptides are involved in the control of sucrose use in nitrogen-fixing nodules.

Rohrig, Horst; Schmidt, Jurgen; Miklashevichs, Edvins; Schell, Jeff; John, Michael

2002-01-01

246

Yeast expression platforms  

Microsoft Academic Search

Yeasts provide attractive expression platforms. They combine ease of genetic manipulations and the option for a simple fermentation\\u000a design of a microbial organism with the capabilities of an eukaryotic organism to secrete and to modify a protein according\\u000a to a general eukaryotic scheme. For platform applications, a range of yeast species has been developed during the last decades.\\u000a We present

Erik Böer; Gerhard Steinborn; Gotthard Kunze; Gerd Gellissen

2007-01-01

247

Sucrose substitutes affect the cariogenic potential of Streptococcus mutans biofilms.  

PubMed

Streptococcus mutans is considered the primary etiologic agent of dental caries and contributes significantly to the virulence of dental plaque, especially in the presence of sucrose. To avoid the role of sucrose on the virulence factors of S. mutans, sugar substitutes are commonly consumed because they lead to lower or no production of acids and interfere with biofilm formation. This study aimed to investigate the contribution of sugar substitutes in the cariogenic potential of S. mutans biofilms. Thus, in the presence of sucrose, glucose, sucralose and sorbitol, the biofilm mass was quantified up to 96 h, the pH of the spent culture media was measured, the expression of biofilm-related genes was determined, and demineralization challenge experiments were conduct in enamel fragments. The presence of sugars or sugar substitutes profoundly affected the expression of spaP, gtfB, gtfC, gbpB, ftf, vicR and vicX in either biofilm or planktonic cells. The substitution of sucrose induced a down-regulation of most genes involved in sucrose-dependent colonization in biofilm cells. When the ratio between the expression of biofilm and planktonic cells was considered, most of those genes were down-regulated in biofilm cells in the presence of sugars and up-regulated in the presence of sugar substitutes. However, sucralose but not sorbitol fulfilled the purpose of reducing the cariogenic potential of the diet since it induced the biofilm formation with the lowest biomass, did not change the pH of the medium and led to the lowest lesion depth in the cariogenic challenge. PMID:24481032

Durso, S C; Vieira, L M; Cruz, J N S; Azevedo, C S; Rodrigues, P H; Simionato, M R L

2014-01-01

248

Low sucrose levels promote extensive Streptococcus mutans-induced dental caries.  

PubMed Central

One-tenth percent sucrose significantly promotes dental caries induced by Streptococcus mutans in young gnotobiotic rats. Maximum caries activity was observed in rats provided a purified diet containing 3% sucrose.

Michalek, S M; McGhee, J R; Shiota, T; Devenyns, D

1977-01-01

249

Viral induced yeast apoptosis.  

PubMed

In an analogous system to mammals, induction of an apoptotic cell death programme (PCD) in yeast is not only restricted to various exogenous factors and stimuli, but can also be triggered by viral killer toxins and viral pathogens. In yeast, toxin secreting killer strains are frequently infected with double-stranded (ds)RNA viruses that are responsible for killer phenotype expression and toxin secretion in the infected host. In most cases, the viral toxins are either pore-forming proteins (such as K1, K2, and zygocin) that kill non-infected and sensitive yeast cells by disrupting cytoplasmic membrane function, or protein toxins (such as K28) that act in the nucleus by blocking DNA synthesis and subsequently causing a G1/S cell cycle arrest. Interestingly, while all these virus toxins cause necrotic cell death at high concentration, they trigger caspase- and ROS-mediated apoptosis at low-to-moderate concentration, indicating that even low toxin doses are deadly by triggering PCD in enemy cells. Remarkably, viral toxins are not solely responsible for cell death induction in vivo, as killer viruses themselves were shown to trigger apoptosis in non-infected yeast. Thus, as killer virus-infected and toxin secreting yeasts are effectively protected and immune to their own toxin, killer yeasts bear the intrinsic potential to dominate over time in their natural habitat. PMID:18291112

Schmitt, Manfred J; Reiter, Jochen

2008-07-01

250

By-products in the fermentation of sucrose by different Zymomonas -strains  

Microsoft Academic Search

Eight Zymomonas strains were compared with respect to their sucrose hydrolysing activity and subsequent ethanol, levan and sorbitol formation. The ethanol yields obtained were within narrow limits, 0.40–0.43 g·g-1 of sucrose. The distribution of by-products differed significantly between the strains tested. A low sucrose hydrolysis rate seemed to be associated with the formation of levan and a high sucrose hydrolysis

Liisa Viikari; Raija Gisler

1986-01-01

251

Research progresses on the key enzymes involved in sucrose metabolism in maize.  

PubMed

Sucrose, as the major product of photosynthesis, is a vital metabolite and signaling molecule in higher plants. Three enzymes are responsible for the synthesis, transport, and degradation of sucrose. In this article, the gene structure, expression and regulation, and the physiological functions of the key enzymes involved in sucrose metabolism in maize are reviewed, moreover, the existing problems of the sucrose metabolism research were discussed in detail, and we present our ideas for future research. PMID:23318271

Ren, Xiaodong; Zhang, Junjie

2013-03-01

252

Sucrose, lactose, and glucose tolerance in northern Alaskan Eskimos1' 2  

Microsoft Academic Search

Sucrose tolerance tests were performed on several adult Eskimos who reported a history of intolerance to sweets. Six experienced severe diarrhea and a rise in capillary blood glucose of less than 20 mg\\/100 ml after a 50-g oral dose of sucrose. The Eskimo apparently exhibits a higher incidence of sucrose intolerance than does any other population tested. This condition may

R. Raines Bell; H. H. Draper; J. G. Bergan

253

Reinforcement Value and Substitutability of Sucrose and Wheel Running: Implications for Activity Anorexia  

ERIC Educational Resources Information Center

Choice between sucrose and wheel-running reinforcement was assessed in two experiments. In the first experiment, ten male Wistar rats were exposed to concurrent VI 30 s VI 30 s schedules of wheel-running and sucrose reinforcement. Sucrose concentration varied across concentrations of 2.5, 7.5, and 12.5%. As concentration increased, more behavior…

Belke, Terry W.; Duncan, Ian D.; Pierce, W. David

2006-01-01

254

Persistence of Preference for a Flavor Presented in Simultaneous Compound With Sucrose  

Microsoft Academic Search

Rats exposed to a simultaneous compound of a flavor and sucrose subsequently exhibited a preference for the flavor over water. This preference persisted across repeated testing even though the flavor was presented in the absence of sucrose. The preference did, however, extinguish if the rats were hungry when trained or tested, or if they had been reexposed to sucrose between

Justin A. Harris; Fiona L. Shand; Louisa Q. Carroll; R. Frederick Westbrook

2004-01-01

255

Adaptation of Sucrose Metabolism in the Escherichia coli Wild-Type Strain EC3132  

Microsoft Academic Search

Although Escherichia coli strain EC3132 possesses a chromosomally encoded sucrose metabolic pathway, its growth on low sucrose concentrations (5 mM) is unusually slow, with a doubling time of 20 h. In this report we describe the subcloning and further characterization of the corresponding csc genes and adjacent genes. The csc regulon comprises three genes for a sucrose permease, a fructokinase,

Knut Jahreis; Lars Bentler; Jurgen Bockmann; Stephan Hans; Astrid Meyer; Jorg Siepelmeyer; Joseph W. Lengeler

2002-01-01

256

Aspects of sucrose transport in stem parenchyma of sweet sorghum. [Sorghum bicolor  

SciTech Connect

Sweet sorghum (Sorghum bicolor (L.) Moench) is a sucrose-storing crop with a storage tissue anatomically similar to that of sugarcane (Saccharum spp.). However, recent evidence suggests that sweet sorghum may be biochemically different from sugarcane. /sup 14/C-sucrose uptake was studied in excised tissue discs from fully-elongated internodes of Rio sweet sorghum. Washout studies gave results consistent with a 3 compartment system. After 3 hours of uptake, most of the /sup 14/C was found in the vacuole compartment, and was determined by HPLC to be sucrose. Total sucrose uptake consisted of a PCMBS-sensitive (active) and a PCMBS-insensitive (passive) component. Active sucrose uptake had a pH optimum of 4.5. Total sucrose uptake was negatively correlated with the internal sucrose content of the tissue. Fructosyl-labelled /sup 14/C-sucrose was not randomized during uptake, suggesting that sucrose cleavage is not a requirement for sucrose uptake in sweet sorghum. This data suggests that in sweet sorghum, sucrose is transported intact by a specific carrier, as opposed to the sucrose-cleavage-and-resynthesis transport system that apparently operates in sugarcane.

Lingle, S.E.

1987-08-01

257

Intra-Accumbens Amphetamine Increases the Conditioned Incentive Salience of Sucrose Reward: Enhancement of Reward \\  

Microsoft Academic Search

Amphetamine microinjection into the nucleus accumbens shell enhanced the ability of a Pavlovian reward cue to trigger in- creased instrumental performance for sucrose reward in a pure conditioned incentive paradigm. Rats were first trained to press one of two levers to obtain sucrose pellets. They were separately conditioned to associate a Pavlovian cue (30 sec light) with free sucrose pellets.

Cindy L. Wyvell; Kent C. Berridge

2000-01-01

258

Sugar utilization patterns and respiro-fermentative metabolism in the baker's yeast Torulaspora delbrueckii.  

PubMed

The highly osmo- and cryotolerant yeast species Torulaspora delbrueckii is an important case study among the non-Saccharomyces yeast species. The strain T. delbrueckii PYCC 5321, isolated from traditional corn and rye bread dough in northern Portugal, is considered particularly interesting for the baking industry. This paper reports the sugar utilization patterns of this strain, using media with glucose, maltose and sucrose, alone or in mixtures. Kinetics of growth, biomass and ethanol yields, fermentation and respiration rates, hydrolase activities and sugar uptake rates were used to infer the potential applied relevance of this yeast in comparison to a conventional baker's strain of Saccharomyces cerevisiae. The results showed that both maltase and maltose transport in T. delbrueckii were subject to glucose repression and maltose induction, whereas invertase was subject to glucose control but not dependent on sucrose induction. A comparative analysis of specific sugar consumption rates and transport capacities suggests that the transport step limits both glucose and maltose metabolism. Specific rates of CO(2) production and O(2) consumption showed a significantly higher contribution of respiration to the overall metabolism in T. delbrueckii than in S. cerevisiae. This was reflected in the biomass yields from batch cultures and could represent an asset for the large-scale production of the former species. This work contributes to a better understanding of the physiology of a non-conventional yeast species, with a view to the full exploitation of T. delbrueckii by the baking industry. PMID:17322210

Alves-Araújo, C; Pacheco, A; Almeida, M J; Spencer-Martins, I; Leão, C; Sousa, M J

2007-03-01

259

Effect of Dietary Intake of Avocado Oil and Olive Oil on Biochemical Markers of Liver Function in Sucrose-Fed Rats  

PubMed Central

Metabolic changes, along with cardiovascular and hepatic factors, are associated with the development of diseases such as diabetes, dyslipidemia, and obesity. We evaluated the effect of avocado oil supplementation (centrifuged and solvent extracted), compared with olive oil, upon the hepatic function in sucrose-fed rats. Twenty-five rats were divided into five groups: control (basal diet), a sucrose-fed group (basal diet plus 30% sucrose solution), and three other groups (S-OO, S-AOC, and S-AOS, indicating basal diet plus 30% sucrose solution plus olive oil OO, avocado oil extracted by centrifugation AOC or using solvent AOS, resp.). Glucose, total cholesterol, triglycerides, total protein, albumin, globulin, direct bilirubin, glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, alkaline phosphatase, cholinesterase, and ?-amylase concentrations were determined and avocado oil effect on them was studied. In some cases the induced metabolic alteration significantly affected total protein and bilirubin levels and also had a highly significant effect on ?-amylase levels. AOC and AOS exhibited effects similar to those of olive oil, according to the nonsignificant difference in fatty acid profile observed by other authors. Avocado oil consumption could be beneficial in the control of altered metabolic profile illnesses as it presents effects on hepatic function biochemical markers similar to olive oil.

Carvajal-Zarrabal, Octavio; Nolasco-Hipolito, Cirilo; Aguilar-Uscanga, Ma. Guadalupe; Melo Santiesteban, Guadalupe; Hayward-Jones, Patricia M.; Barradas-Dermitz, Dulce Ma.

2014-01-01

260

High-field/ high-frequency EPR study on stable free radicals formed in sucrose by gamma-irradiation.  

PubMed

The EPR spectrum of sucrose irradiated by high-energy radiation is complex due to the presence of more than one radical species. In order to decompose the spectrum and elucidate the radical magnetic parameters a high-field (HF(-)EPR) study on stable free radicals in gamma-irradiated polycrystalline sucrose (table sugar) was performed at three different high frequencies--94, 190 and 285 GHz as well as at the conventional X-band. We suggest a presence of three stable radicals R1, R2 and R3 as the main radical species. Due to the increase of g-factor resolution at high fields the g-tensors of these radicals could be extracted by accurate simulations. The moderate g-anisotropy suggests that all three radicals are carbon-centred. Results from an earlier ENDOR study on X-irradiated sucrose single crystals (Vanhaelewyn et al., Appl Radiat Isot, 52, 1221 (2000)) were used for analyzing of the spectra in more details. It was confirmed that the strongest hyperfine interaction has a relatively small anisotropy, which indicates either the absence of alpha-protons or a strongly distorted geometry of the radicals. PMID:16753832

Georgieva, Elka R; Pardi, Luca; Jeschke, Gunnar; Gatteschi, Dante; Sorace, Lorenzo; Yordanov, Nicola D

2006-06-01

261

A non-destructive method for quantification the irradiation doses of irradiated sucrose using Vis/NIR spectroscopy.  

PubMed

This article proposes a new method for fast discrimination of irradiation doses of sucrose based on visible-near infrared (Vis/NIR) spectroscopy technology. 250 sucrose samples were categorized into five groups to be irradiated at 0, 1.5, 3.0, 4.5, 6.0 kGy respectively and prepared for the discrimination analysis. The 50 samples of each group were randomly divided into a calibration set containing 40 samples, and a validation set containing the remaining 10 samples. Principal component clustering analysis (PCCA) was applied for the extraction of principal components (PCs) and for clustering analysis. The first five PCs were regarded as the inputs to develop the back propagation neural network (BPNN) model. The performance of the model was validated by the 50 unknown samples and the BPNN achieved an excellent precision and recognition ration of 100%. The results indicated that Vis/NIR spectroscopy could be utilized as a rapid and non-destructive method for the classification of different irradiation doses of irradiated sucrose. PMID:23041915

Gong, Aiping; Qiu, Zhengjun; He, Yong; Wang, Zhiping

2012-12-01

262

A non-destructive method for quantification the irradiation doses of irradiated sucrose using Vis/NIR spectroscopy  

NASA Astrophysics Data System (ADS)

This article proposes a new method for fast discrimination of irradiation doses of sucrose based on visible-near infrared (Vis/NIR) spectroscopy technology. 250 sucrose samples were categorized into five groups to be irradiated at 0, 1.5, 3.0, 4.5, 6.0 kGy respectively and prepared for the discrimination analysis. The 50 samples of each group were randomly divided into a calibration set containing 40 samples, and a validation set containing the remaining 10 samples. Principal component clustering analysis (PCCA) was applied for the extraction of principal components (PCs) and for clustering analysis. The first five PCs were regarded as the inputs to develop the back propagation neural network (BPNN) model. The performance of the model was validated by the 50 unknown samples and the BPNN achieved an excellent precision and recognition ration of 100%. The results indicated that Vis/NIR spectroscopy could be utilized as a rapid and non-destructive method for the classification of different irradiation doses of irradiated sucrose.

Gong, Aiping; Qiu, Zhengjun; He, Yong; Wang, Zhiping

2012-12-01

263

Oxygen requirements of yeasts.  

PubMed Central

Type species of 75 yeast genera were examined for their ability to grow anaerobically in complex and mineral media. To define anaerobic conditions, we added a redox indicator, resazurin, to the media to determine low redox potentials. All strains tested were capable of fermenting glucose to ethanol in oxygen-limited shake-flask cultures, even those of species generally regarded as nonfermentative. However, only 23% of the yeast species tested grew under anaerobic conditions. A comparative study with a number of selected strains revealed that Saccharomyces cerevisiae stands out as a yeast capable of rapid growth at low redox potentials. Other yeasts, such as Torulaspora delbrueckii and Candida tropicalis, grew poorly mu max, 0.03 and 0.05 h-1, respectively) under anaerobic conditions in mineral medium supplemented with Tween 80 and ergosterol. The latter organisms grew rapidly under oxygen limitation and then displayed a high rate of alcoholic fermentation. It can be concluded that these yeasts have hitherto-unidentified oxygen requirements for growth. Images

Visser, W; Scheffers, W A; Batenburg-van der Vegte, W H; van Dijken, J P

1990-01-01

264

Mapping Yeast Transcriptional Networks  

PubMed Central

The term “transcriptional network” refers to the mechanism(s) that underlies coordinated expression of genes, typically involving transcription factors (TFs) binding to the promoters of multiple genes, and individual genes controlled by multiple TFs. A multitude of studies in the last two decades have aimed to map and characterize transcriptional networks in the yeast Saccharomyces cerevisiae. We review the methodologies and accomplishments of these studies, as well as challenges we now face. For most yeast TFs, data have been collected on their sequence preferences, in vivo promoter occupancy, and gene expression profiles in deletion mutants. These systematic studies have led to the identification of new regulators of numerous cellular functions and shed light on the overall organization of yeast gene regulation. However, many yeast TFs appear to be inactive under standard laboratory growth conditions, and many of the available data were collected using techniques that have since been improved. Perhaps as a consequence, comprehensive and accurate mapping among TF sequence preferences, promoter binding, and gene expression remains an open challenge. We propose that the time is ripe for renewed systematic efforts toward a complete mapping of yeast transcriptional regulatory mechanisms.

Hughes, Timothy R.; de Boer, Carl G.

2013-01-01

265

21 CFR 172.896 - Dried yeasts.  

Code of Federal Regulations, 2013 CFR

...172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis ) and dried torula yeast (Candida utilis ) may be safely used in food provided the total folic acid content of the yeast does not exceed 0.04 milligram...

2013-04-01

266

Magnetic birefringence of iron oxyhydroxide nanoparticles stabilised by sucrose  

NASA Astrophysics Data System (ADS)

Magnetically induced optical birefringence is used to investigate pharmaceutically important iron-sucrose aqueous suspensions. XRD and TEM measurements of the system of oxyhydroxide particles stabilised by sucrose have shown that this system contains iron oxyhydroxide in the form of 2-5 nm particles. The mineral form of the iron-core is suggested to be akaganeite. Anisotropy of the optical polarizability and magnetic susceptibility of akaganeite nanoparticles are calculated. The permanent dipole moment obtained for the nanoparticles studied was found to be negligible, in agreement with the characteristic superparamagnetic behaviour of the magnetic nanoparticles observed at room temperature. The Neel temperature of these nanoparticles is estimated as below 276 K. The results obtained are discussed against a background of the earlier studies of similar nanoscale systems.

Koralewski, M.; Pochylski, M.; Gierszewski, J.

2011-05-01

267

Dopaminergic modulation of sucrose acceptance behavior in Drosophila.  

PubMed

For an animal to survive in a constantly changing environment, its behavior must be shaped by the complex milieu of sensory stimuli it detects, its previous experience, and its internal state. Although taste behaviors in the fly are relatively simple, with sugars eliciting acceptance behavior and bitter compounds avoidance, these behaviors are also plastic and are modified by intrinsic and extrinsic cues, such as hunger and sensory stimuli. Here, we show that dopamine modulates a simple taste behavior, proboscis extension to sucrose. Conditional silencing of dopaminergic neurons reduces proboscis extension probability, and increased activation of dopaminergic neurons increases extension to sucrose, but not to bitter compounds or water. One dopaminergic neuron with extensive branching in the primary taste relay, the subesophageal ganglion, triggers proboscis extension, and its activity is altered by satiety state. These studies demonstrate the marked specificity of dopamine signaling and provide a foundation to examine neural mechanisms of feeding modulation in the fly. PMID:22405204

Marella, Sunanda; Mann, Kevin; Scott, Kristin

2012-03-01

268

Sucrose Monoester Micelles Size Determined by Fluorescence Correlation Spectroscopy (FCS)  

PubMed Central

One of the several uses of sucrose detergents, as well as other micelle forming detergents, is the solubilization of different membrane proteins. Accurate knowledge of the micelle properties, including size and shape, are needed to optimize the surfactant conditions for protein purification and membrane characterization. We synthesized sucrose esters having different numbers of methylene subunits on the substituent to correlate the number of methylene groups with the size of the corresponding micelles. We used Fluorescence Correlation Spectroscopy (FCS) and two photon excitation to determine the translational D of the micelles and calculate their corresponding hydrodynamic radius, Rh. As a fluorescent probe we used LAURDAN (6-dodecanoyl-2-dimethylaminonaphthalene), a dye highly fluorescent when integrated in the micelle and non-fluorescent in aqueous media. We found a linear correlation between the size of the tail and the hydrodynamic radius of the micelle for the series of detergents measured.

Sanchez, Susana A.; Gratton, Enrico; Zanocco, Antonio L.; Lemp, Else; Gunther, German

2011-01-01

269

Roughness effect on the overall growth rate of sucrose crystals  

NASA Astrophysics Data System (ADS)

The roughness effect on crystal growth rate was investigated at 35C in a fluidized bed crystallizer and in a batch crystallizer. The crystallization of sucrose in pure aqueous solutions was the study subject. The results show that the sucrose crystals exhibit time-dependent growth rate. The overall growth rate decreased continually with time until a constant value was reached, that corresponds to a decrease of 40% considering the experiments of 13 and 63 min duration in the fluidized bed crystallizer. The decrease of the growth rates with the contact time between crystals and supersaturated solution was interpreted in terms of the increase of surfaces' roughness. According to SEM micrographs, the surface roughness increases significantly with residence time and supersaturation. The roughness appears to be the result of faulty integration of growth clusters in the crystal surface. The batch experiments show that the surface roughness acts like a strong impurity. The results were interpreted according to the Kubota-Mullin model.

Ferreira, A.; Faria, N.; Rocha, F.

2008-01-01

270

Preparation and performance of immobilized yeast cells in columns containing no inert carrier. [Schizosaccharomyces pombe  

SciTech Connect

Schizosaccharomyes pombe was cultivated in a medium of glucose (10 g/l), malt extract (3 g/l), yeast extract (3 g/l), and bactopeptone (5 g/l) to form flocs. More than 95% of the cell population were flocculated. Variation in glucose concentration (from 10 to 11 g/l) did not affect flocculation. Yeast extract helped induce flocculation. Application of the immobilized yeast for the continuous production of ethanol was tested in a column reactor. Soft yeast flocs (50-200 mesh) underwent morphological changes to heavy particles (0.1-9.3 cm diameter) after continuously being fed with fresh substrates in the column. Productivity as high as 87 g EtOH/l/hour was obtained when a 150 g/l glucose medium was fed. The performance of this yeast reactor was stable over a two-month period. The ethanol yield was 97% of the theoretical maximum based upon glucose consumed. (Refs. 16).

Hsiao, H.Y.; Chiang, L.C.; Yang, C.M.; Chen, L.F.; Tsao, G.T.

1983-02-01

271

Microbiological Characteristics and Physiological Functionality of New Records of Yeasts from Wild Flowers in Yokjido, Korea  

PubMed Central

Two new yeast records, Cryptococcus adeliensis YJ19-2 and Cryptococcus uzbekistanensis YJ10-4 were screened from 60 yeasts strains that were isolated and identified from wild flowers in Yokjido, Gyeongsangnam-do, Korea. The morphological and cultural characteristics of the newly recorded yeasts and the physiological functionalities of the supernatants and cell-free extracts obtained from their cultures were investigated. The two newly recorded yeasts did not form ascospores and pseudomycelia. They also grew well in yeast extract-peptone-dextrose broth. C. uzbekistanensis YJ10-4 grew in a vitamin-free medium and was also tolerant to sugar and salt. Antihypertensive angiotensin I-converting enzyme inhibitory activity of the supernatant from C. adeliensis YJ19-2 was high (71.8%) and its cell-free extract also showed very high (81.2%) antidiabetic á-glucosidase inhibitory activity.

Hyun, Se-Hee

2014-01-01

272

A Wound-Inducible Potato Proteinase Inhibitor Gene Expressed in Non-Tuber-Bearing Species Is Not Sucrose Inducible 1  

PubMed Central

Sequences homologous to a potato cathepsin D inhibitor cDNA, p749, were identified in the genomic DNA of tomato (Lycopersicon esculentum) and of two non-tuber-bearing potato species (Solanum etuberosum and S. brevidens) by means of Southern blot analysis. The expression of these p749 genes in leaves was induced at the RNA level in response to wounding. High levels of p749 transcripts were detected in polyadenylated RNA extracted from locally wounded leaves 12 h after wounding. Systemic induction of the cathepsin D inhibitor gene also occurred in nonwounded leaves of wounded plants. Both potato and tomato leaves treated with the oligosaccharide chitosan showed an induced accumulation of p749 transcripts. Even though the cathepsin D inhibitor genes from tomato and from non-tuber-bearing potato species are wound inducible, they could not be induced in leaf explants cultured on medium containing very high concentrations of sucrose. Only leaf explants from the tuber-bearing potato (S. tuberosum) accumulated p749 transcripts when cultured on high sucrose medium. A sequence related to the 22-kD potato proteinase inhibitor cDNA, p34021, was identified in tomato by means of genomic Southern blot analysis. Northern blot hybridization showed that p34021 transcripts accumulated in potato (S. tuberosum) leaf explants, but not in tomato explants, when cultured on high sucrose medium. This study demonstrates that the expression of a potato cathepsin D inhibitor gene in tomato and in non-tuber-bearing potato species is wound inducible, but not sucrose inducible. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Hansen, Joel D.; Hannapel, David J.

1992-01-01

273

Enhancement of Sucrose Sweetness with Soluble Starch in Humans  

Microsoft Academic Search

The effect of soluble starch (acid-modified starch) on taste intensity was investigated in human subjects. Different concentrations of sucrose (Suc), six sweeteners, NaCl, quinine-HCl (QHCl) and citric acid (Cit) were dissolved in either distilled water (DW; standard) or starch solution (test solution). The solutions were presented to naive subjects and each subject was requested to taste and compare the sweetness

Norikazu Kanemaru; Shuitsu Harada; Yasuo Kasahara

2002-01-01

274

Model of micropore closure in hard carbon prepared from sucrose  

Microsoft Academic Search

A series of samples pyrolysed to different temperatures were synthesized from dewatered sucrose. These samples were characterised by wide-angle X-Ray scattering (WAXS), small-angle X-Ray scattering (SAXS), BET surface area and CO2 gas adsorption measurements. WAXS and SAXS measurements were used to determine the average number of graphene sheets stacked in a parallel fashion and the average micropore size (8–10 Å

E. R. Buiel; A. E. George; J. R. Dahn

1999-01-01

275

Electrons trapped in single crystals of sucrose: Induced spin densities  

SciTech Connect

Electrons are trapped at intermolecular sites in single crystals of sucrose {ital X} irradiated at 4.2 K. The coupling tensors for the hyperfine couplings between the electron and surrounding protons have been deduced from electron-nuclear double resonance (ENDOR) data. Electron spin densities at nearby hydroxy protons are positive, whereas spin densities at the more remote protons of carbon-bound hydrogen atoms are negative. The origin of these negative spin densities is discussed.

Box, H.C.; Budzinski, E.E.; Freund, H.G. (Biophysics Department, Roswell Park Memorial Institute, Buffalo, New York 14263 (USA))

1990-07-01

276

Steroid hormone excretion is enhanced by sucrose feeding to rats  

SciTech Connect

The hypothesis tested was that feeding rats sucrose rather than invert sugar (50:50 mixture of glucose and fructose) or cornstarch would result in a more rapid excretion of intravenously injected 1,2-/sup 3/H aldosterone or 1,2,6,7-/sup 3/H cortisol. The three carbohydrate sources provided 45% of dietary energy when fed, respectively, to one of three groups of 10 male, Sprague Dawley rats. After 4 or 8 weeks of ad lib feeding of the three diets 5 ..mu..CI of /sup 3/H-labeled hormones were injected intravenously and % recovery in urine and feces was measured for 4 days by liquid scintillation counting. Nearly 90% of the /sup 3/H injected as 1,2-/sup 3/H aldosterone was recovered over 4 days in the excreta of the sucrose fed rats. This recovery of /sup 3/H from aldosterone was significantly greater (P < 0.01) than when invert sugar (65%) or cornstarch (60%) were fed. The recovery of /sup 3/H from intravenously injected 1,2,6,7-/sup 3/H cortisol followed a similar pattern. The authors anticipate that the excretion of all metabolic end products and xenobiotics excreted as glucuronides would be enhanced by sucrose feeding. Oxocarbonium ions from the glucose portion of sucrose digestion in the mammalian small intestine are thought to compete with oxocarbonium ions from the glucuronic acid portion of glucuronide hydrolysis. Such competition may slow glucuronide hydrolysis and promote glucuronide excretion, including the glucuronides derived from aldosterone and cortisol.

Kruger, T.C.; Hsu, H.; Saunders, J.P.; Kim, S.S.; Given-Proctor, J.; Ahrens, R.A.

1986-03-01

277

Sucrose self-administration and CNS activation in the rat.  

PubMed

We have previously reported that administration of insulin into the arcuate nucleus of the hypothalamus decreases motivation for sucrose, assessed by a self-administration task, in rats. Because the pattern of central nervous system (CNS) activation in association with sucrose self-administration has not been evaluated, in the present study, we measured expression of c-Fos as an index of neuronal activation. We trained rats to bar-press for sucrose, according to a fixed-ratio (FR) or progressive-ratio (PR) schedule and mapped expression of c-Fos immunoreactivity in the CNS, compared with c-Fos expression in handled controls. We observed a unique expression of c-Fos in the medial hypothalamus (the arcuate, paraventricular, retrochiasmatic, dorsomedial, and ventromedial nuclei) in association with the onset of PR performance, and expression of c-Fos in the lateral hypothalamus and the bed nucleus of stria terminalis in association with the onset of FR performance. c-Fos expression was increased in the nucleus accumbens of both FR and PR rats. Our study emphasizes the importance of both hypothalamic energy homeostasis circuitry and limbic circuitry in the performance of a food reward task. Given the role of the medial hypothalamus in regulation of energy balance, our study suggests that this circuitry may contribute to reward regulation within the larger context of energy homeostasis. PMID:21307361

Figlewicz, Dianne P; Bennett-Jay, Jennifer L; Kittleson, Sepideh; Sipols, Alfred J; Zavosh, Aryana

2011-04-01

278

Diffusion of sucrose and dextran through agar gel membranes.  

PubMed

Mass transfer limitations severely impede the performance of bioreactions involving large molecules by gel-entrapped microorganisms. This paper describes a quantitative investigation of such diffusional limitations in agar gel membranes. Sucrose and commercial dextran fractions with (weight-average) molecular weights ranging from 10,000 to 2,000,000 Da were used as standard diffusants. For all tested solutes but sucrose, the values of the agar/water partition coefficients highlighted steric hindrance at the entrance of the membrane pores. The effective diffusivity of sucrose in agar was similar to that in water. All dextran fractions, however, displayed restricted diffusion in the agar membranes. Their effective diffusivities were a decreasing function of the agar content of the gel membrane (0.5, 1.0, or 1.5% w/v). The effective diffusivity in a given membrane decreased as the molecular weight of the diffusing molecule increased. T500 (Mw = 470,000 Da) and T2000 (Mw = 1,950,000 Da) fractions were unable to diffuse through 1.0 or 1.5% agar membranes. The diffusion data did not agree with the classical (Renkin) model for a hard sphere diffusing through a cylindrical pore. These results are discussed in terms of gel and diffusant characteristics. PMID:7505595

Lebrun, L; Junter, G A

1993-12-01

279

Yeast killer systems.  

PubMed Central

The killer phenomenon in yeasts has been revealed to be a multicentric model for molecular biologists, virologists, phytopathologists, epidemiologists, industrial and medical microbiologists, mycologists, and pharmacologists. The surprisingly widespread occurrence of the killer phenomenon among taxonomically unrelated microorganisms, including prokaryotic and eukaryotic pathogens, has engendered a new interest in its biological significance as well as its theoretical and practical applications. The search for therapeutic opportunities by using yeast killer systems has conceptually opened new avenues for the prevention and control of life-threatening fungal diseases through the idiotypic network that is apparently exploited by the immune system in the course of natural infections. In this review, the biology, ecology, epidemiology, therapeutics, serology, and idiotypy of yeast killer systems are discussed.

Magliani, W; Conti, S; Gerloni, M; Bertolotti, D; Polonelli, L

1997-01-01

280

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

2008-02-28

281

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

282

Fast and sensitive detection of genetically modified yeasts in wine.  

PubMed

In this work, a novel screening methodology based on the combined use of multiplex polymerase chain reaction (PCR) and capillary gel electrophoresis with laser induced fluorescence (CGE-LIF) is developed for the fast and sensitive detection of genetically modified yeasts in wine. As model, a recombinant EKD-13 Saccaromyces cerevisiae strain was selected and different wines were prepared using either recombinant or conventional yeasts. Special emphasis is put on the yeast DNA extraction step, exploring different commercial and non-commercial methods, in order to overcome the important difficulty of obtaining amplifiable DNA from wine samples. To unequivocally detect the transgenic yeast, two specific segments of the transgenic construction were amplified. In addition, a third primer pair was used as amplification control to confirm the quality of the yeast DNA obtained from the extraction step. CGE-LIF provides high sensitivity, good analysis speed and impressive resolution of DNA fragments, making this technique very convenient to optimize multiplex PCR parameters and to analyze the amplified DNA fragments. Thus, the CGE-LIF method provided %RSD values for DNA migration times lower than 0.82% (n=10) with the same capillary and lower than 1.92% (n=15) with three different capillaries, allowing the adequate size determination of the PCR products with an error lower than 4% compared to the theoretically expected. The whole method developed in this work requires less than one working day and grants the sensitive detection of transgenic yeasts in wine samples. PMID:21296357

León, Carlos; García-Cañas, Virginia; González, Ramón; Morales, Pilar; Cifuentes, Alejandro

2011-10-21

283

On the mechanisms of glycolytic oscillations in yeast.  

PubMed

This work concerns the cause of glycolytic oscillations in yeast. We analyse experimental data as well as models in two distinct cases: the relaxation-like oscillations seen in yeast extracts, and the sinusoidal Hopf oscillations seen in intact yeast cells. In the case of yeast extracts, we use flux-change plots and model analyses to establish that the oscillations are driven by on/off switching of phosphofructokinase. In the case of intact yeast cells, we find that the instability leading to the appearance of oscillations is caused by the stoichiometry of the ATP-ADP-AMP system and the allosteric regulation of phosphofructokinase, whereas frequency control is distributed over the reaction network. Notably, the NAD+/NADH ratio modulates the frequency of the oscillations without affecting the instability. This is important for understanding the mutual synchronization of oscillations in the individual yeast cells, as synchronization is believed to occur via acetaldehyde, which in turn affects the frequency of oscillations by changing this ratio. PMID:15943800

Madsen, Mads F; Danø, Sune; Sørensen, Preben G

2005-06-01

284

Vaginal Yeast Infections (For Parents)  

MedlinePLUS

... a common infection caused by a yeast called candida albicans (a type of fungus). Yeast infections usually ... the vagina, it is known as vulvovaginal candidiasis . Candida can overgrow for many reasons. Stress, pregnancy, and ...

285

L-arabinose fermenting yeast  

DOEpatents

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

Zhang, Min (Lakewood, CO); Singh, Arjun (Lakewood, CO); Knoshaug, Eric (Golden, CO); Franden, Mary Ann (Centennial, CO); Jarvis, Eric (Boulder, CO); Suominen, Pirkko (Maple Grove, MN)

2010-12-07

286

Sugarcane bagasse hydrolysis using yeast cellulolytic enzymes.  

PubMed

Ethanol fuel production from lignocellulosic biomass is emerging as one of the most important technologies for sustainable development. To use this biomass, it is necessary to circumvent the physical and chemical barriers presented by the cohesive combination of the main biomass components, which hinders the hydrolysis of cellulose and hemicellulose into fermentable sugars. This study evaluated the hydrolytic capacity of enzymes produced by yeasts, isolated from the soils of the Brazilian Cerrado biome (savannah) and the Amazon region, on sugarcane bagasse pre-treated with H2SO4. Among the 103 and 214 yeast isolates from the Minas Gerais Cerrado and the Amazon regions, 18 (17.47%) and 11 (5.14%) isolates, respectively, were cellulase-producing. Cryptococcus laurentii was prevalent and produced significant ?- glucosidase levels, which were higher than the endo- and exoglucanase activities. In natura sugarcane bagasse was pre-treated with 2% H2SO4 for 30 min at 150oC. Subsequently, the obtained fibrous residue was subjected to hydrolysis using the Cryptococcus laurentii yeast enzyme extract for 72 h. This enzyme extract promoted the conversion of approximately 32% of the cellulose, of which 2.4% was glucose, after the enzymatic hydrolysis reaction, suggesting that C. laurentii is a good ?-glucosidase producer. The results presented in this study highlight the importance of isolating microbial strains that produce enzymes of biotechnological interest, given their extensive application in biofuel production. PMID:23851270

Souza, Angelica Cristina de; Carvalho, Fernanda Paula; Silva e Batista, Cristina Ferreira; Schwan, Rosane Freitas; Dias, Disney Ribeiro

2013-10-28

287

Persisting adiposity following chronic consumption of 10% sucrose solution: Strain differences and behavioural effects.  

PubMed

The metabolic consequences of providing rats with extended access to sugar solutions have varied across studies. The two experiments in this study examined the effects of 8weeks of 24-h access to 10% sucrose solution on adult Wistar rats. This was followed by 6weeks of food restriction with no access to sucrose during which the behavioural effects of prior sucrose consumption on reward-oriented behaviour (Experiment 1) and reversal learning (Experiment 2) were assessed. In a comparison between rat strains, Experiment 1 found that sucrose accelerated weight gain in Albino but not Hooded Wistar rats, while sucrose-fed rats of both strains exhibited elevated fasting blood glucose and resistance to insulin. Importantly, at cull retroperitoneal fat deposits were elevated in sucrose-fed rats, at which point glucose and insulin had resolved to control levels and liver triglyceride content did not differ between groups. Experiment 2 also found that retroperitoneal fat content was higher in sucrose-fed rats at cull, after 6weeks of behavioural testing without sucrose and with restricted access to food, and found a similar effect for epididymal fat. Behavioural testing in Experiment 1 found that sucrose exposure had no effect on habit formation assessed using an outcome devaluation paradigm. However, instrumental responding by sucrose-fed Albino rats was the least affected by pre-feeding, indicating a relationship between sucrose-induced obesity and food-seeking behaviour. In Experiment 2, sucrose-fed and control rats did not differ on a discrimination reversal task. In conclusion, this study demonstrates that the behavioural and metabolic effects of sucrose consumption vary with strain. Further, results indicate that sucrose consumption can lead to lasting increases in adipose tissue stores, a finding which has significant implications for human diets. PMID:24662698

Kendig, Michael D; Rooney, Kieron B; Corbit, Laura H; Boakes, Robert A

2014-05-10

288

Yeast cells proliferation on various strong static magnetic fields and temperatures  

NASA Astrophysics Data System (ADS)

The effect of strong magnetic fields on activities of yeast cells were investigated. Experimental yeast cells were cultured in 5 ml of YPD(Yeast extract Peptone Dextrose) for the number density of yeast cells of 5.0 ±0.2 x 106/ml with various temperatures and magnetic fields up to 10 T. Since the yeast cells were placed in the center of the superconducting magnet, the effect of magnetic force due to the diamagnetism and magnetic gradient was negligibly small. The yeast suspension was opened to air and cultured in shaking condition. The number of yeast cells in the yeast suspension was counted by a counting plate with an optical microscope, and the time dependence of the number density of yeast cells was measured. The time dependence of the number density of yeast cells, ?, of initial part is analyzed in terms of Malthus equation as given by ? = ?o exp(kt), where k is the growth coefficient. It is found that, the growth coefficient under the magnetic field is suppressed compared with the control. The growth coefficient decreasing as increasing magnetic field and is saturated at about 5 T. On the other hand, it is found that the suppression of growth of yeast cells by the magnetic field is diminished at high temperatures.

Otabe, E. S.; Kuroki, S.; Nikawa, J.; Matsumoto, Y.; Ooba, T.; Kiso, K.; Hayashi, H.

2009-03-01

289

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast  

PubMed Central

Spores harboring an ACC1 deletion derived from a diploid Saccharomyces cerevisiae strain, in which one copy of the entire ACC1 gene is replaced with a LEU2 cassette, fail to grow. A chimeric gene consisting of the yeast GAL10 promoter, yeast ACC1 leader, wheat cytosolic acetyl-CoA carboxylase (ACCase) cDNA, and yeast ACC1 3? tail was used to complement a yeast ACC1 mutation. The complementation demonstrates that active wheat ACCase can be produced in yeast. At low concentrations of galactose, the activity of the “wheat gene” driven by the GAL10 promoter is low and ACCase becomes limiting for growth, a condition expected to enhance transgenic yeast sensitivity to wheat ACCase-specific inhibitors. An aryloxyphenoxypropionate and two cyclohexanediones do not inhibit growth of haploid yeast strains containing the yeast ACC1 gene, but one cyclohexanedione inhibits growth of the gene-replacement strains at concentrations below 0.2 mM. In vitro, the activity of wheat cytosolic ACCase produced by the gene-replacement yeast strain is inhibited by haloxyfop and cethoxydim at concentrations above 0.02 mM. The activity of yeast ACCase is less affected. The wheat plastid ACCase in wheat germ extract is inhibited by all three herbicides at concentrations below 0.02 mM. Yeast gene-replacement strains will provide a convenient system for the study of plant ACCases.

Joachimiak, M.; Tevzadze, G.; Podkowinski, J.; Haselkorn, R.; Gornicki, P.

1997-01-01

290

Determination of Growth and Glycerol Production Kinetics of a Wine Yeast Strain Saccharomyces cerevisiae Kalecik 1 in Different Substrate Media  

Microsoft Academic Search

Summary  Glycerol has been known as an important by-product of wine fermentations improving the sensory quality of wine. This study\\u000a was carried out with an endogenic wine yeast strain Saccharomyces cerevisiae Kalecik 1. The kinetics of growth and glycerol biosynthesis were analysed at various initial concentrations of glucose, fructose,\\u000a and sucrose in a batch system. Depending on the determined values of

Seda Karasu Yalçin; Zekiye Ye?im Özba?

2005-01-01

291

Evaluation of YeastIdent and Uni-Yeast-Tek yeast identification systems.  

PubMed Central

The accuracy of the new API YeastIdent system and the Flow Laboratories Uni-Yeast-Tek identification kit with an expanded data base was evaluated in comparison to the API 20C yeast identification system by three laboratories. A total of 489 test isolates were used, biased toward yeasts commonly encountered in clinical specimens. Isolates not in a system's data base were not counted in the evaluation of that system. For isolates in their data base, YeastIdent was 55% accurate and Uni-Yeast-Tek was 40% accurate. By the manufacturer's criteria of reliable identification without additional tests, both systems failed to identify many common and uncommon species. The limited number of substrates and difficulties in assessing results obtained with 11 of the API YeastIdent substrates and apparent errors in the expanded Uni-Yeast-Tek data base appeared to be major factors limiting the accuracy of these systems.

Salkin, I F; Land, G A; Hurd, N J; Goldson, P R; McGinnis, M R

1987-01-01

292

Candida bituminiphila, a novel anamorphic species of yeast.  

PubMed

A novel anamorphic species of yeast belonging to the genus Candida was isolated from tar in Canada. Morphological and physiological observations, as well as phylogenetic analyses, were performed. Conidiophores were produced, were usually short and had sympodial growth, numerous bud scars and a rachis-like structure. They bore one or more conidia. Pseudomycelium was scarcely produced and true mycelium was sparse. No sexual reproduction was observed on corn meal, malt, Gorodkowa, Dextrose Yeast Peptone or V8 agars. Zygoascus hellenicus was physiologically the most closely related species, but it differed from the novel species by its ability to assimilate D-galacturonate and L-rhamnose, ferment sucrose and grow at 37 degrees C. From sequence analysis of the 26S rDNA D1/D2 region, Z. hellenicus and Candida bertae var. bertae were the closest species with 54 and 56 bp substitutions, respectively. Similar results have been obtained from analysis of the 18S rDNA. All these data support the hypothesis that the yeast, named Candida bituminiphila, is a novel species closely related to Z. hellenicus. The holotype and only isolate of C. bituminiphila is strain CBS 8813T (= MUCL 41424T). PMID:11760960

Robert, V; Bonjean, B; Karutz, M; Paschold, H; Peeters, W; Wubbolts, M G

2001-11-01

293

Investigation of the stability of tablets prepared from sucrose and citric acid anhydride utilizing response surface methodology  

Microsoft Academic Search

Inversion of sucrose is a stability problem particularly of candies with acidic taste that contain sucrose and small amounts of organic acids such as citric acid, since the free d-fructose produced by hydrolysis is hygroscopic. The following possibilities were investigated for preventing the hydrolysis of sucrose in tablets containing sucrose and citric acid: Adding various amounts of tri-sodium citrate to

S. Salar Behzadi; Silvester Ölzant; Reinhard Länger; Christian Koban; Frank M. Unger; Helmut Viernstein

2006-01-01

294

Evidence for the presence of a sucrose carrier in immature sugar beet tap roots. [Beta vulgaris L  

SciTech Connect

The objectives of this work were to determine the path of phloem unloading and if a sucrose carrier was present in young sugar beet (Beta vulgaris L.) taproots. The approach was to exploit the characteristics of the sucrose analog, 1{prime}-fluorosucrose (F-sucrose) which is a poor substrate for acid invertase but is a substrate for sucrose synthase. Ten millimolar each of ({sup 3}H) sucrose and ({sup 14}C)F-sucrose were applied in a 1:1 ratio to an abraded region of an attached leaf for 6 hours. ({sup 14}C)F-sucrose was translocated and accumulated in the roots at a higher rate than ({sup 3}H)sucrose. This was due to ({sup 3}H)sucrose hydrolysis along the translocation path. Presence of ({sup 3}H)hexose and ({sup 14}C)F-sucrose in the root apoplast suggested apoplastic sucrose unloading with its subsequent hydrolysis. Labeled F-sucrose uptake by root tissue discs exhibited biphasic kinetics and was inhibited by unlabeled sucrose, indicating that immature roots have the ability for carrier-mediated sucrose transport from the apoplast. Collectively, in vivo and in vitro data indicate that despite sucrose hydrolysis by the wall-bound invertase, sucrose hydrolysis is not entirely essential for sugar accumulation in this tissue.

Lemoine, R.; Daie, J.; Wyse, R. (Rutgers Univ., New Brunswick, NJ (USA))

1988-02-01

295

Mutagen testing with yeast.  

PubMed

This article deals primarily with the practical aspects of mutagen testing with yeast. Equipment necessary for a laboratory where mutagen testing with yeast is performed, and the most commonly used media, are listed. Some general procedures are described and, finally, for those who have little experience with work of this kind, a precise protocol is given for an experiment with stationary phase cells of the strain D7 of Saccharomyces cerevisiae using the heteroallelic ade2 system as the genetic endpoint. Some experimental data were obtained by students following this protocol using the direct-acting mutagen ethyl methanesulfonate (EMS); these data are discussed and analyzed. More details on the various genetic endpoints available in numerous yeast strains and on the interpretation of dose-dependence data, as well as an extended list of yeast literature, can be found in an article by Eckardt and von Borstel in this volume. Further technical advice is provided in our references to Zimmermann (1975), von Borstel (1981), and Zimmermann et al. (1984). PMID:3904715

Eckardt, F; Siede, W

1985-01-01

296

His-65 in the proton-sucrose symporter is an essential amino acid whose modification with site-directed mutagenesis increases transport activity  

PubMed Central

The proton–sucrose symporter that mediates phloem loading is a key component of assimilate partitioning in many higher plants. Previous biochemical investigations showed that a diethyl pyrocarbonate-sensitive histidine residue is at or near the substrate-binding site of the symporter. Among the proton–sucrose symporters cloned to date, only the histidine residue at position 65 of AtSUC1 from Arabidopsis thaliana is conserved across species. To test whether His-65 is involved in the transport reaction, we have used site-directed mutagenesis and functional expression in yeast to determine the significance of this residue in the reaction mechanism. Symporters with mutations at His-65 exhibited a range of activities; for example, the H65C mutant resulted in the complete loss of transport capacity, whereas H65Q was almost as active as wild type. Surprisingly, the H65K and H65R symporters transport sucrose at significantly higher rates (increased Vmax) than the wild-type symporter, suggesting His-65 may be associated with a rate-limiting step in the transport reaction. RNA gel blot and protein blot analyses showed that, with the exception of H65C, the variation in transport activity was not because of alterations in steady-state levels of mRNA or symporter protein. Significantly, those symporters with substitutions of His-65 that remained transport competent were no longer sensitive to inactivation by diethyl pyrocarbonate, demonstrating that this is the inhibitor-sensitive histidine residue. Taken together with our previous results, these data show that His-65 is involved in sucrose binding, and increased rates of transport implicate this region of the protein in the transport reaction.

Lu, Jade M.-Y.; Bush, Daniel R.

1998-01-01

297

The influence of sucrose, 2,4-D, and kinetin on the growth, fine structure, and lignin content of cultured sycamore cells  

Microsoft Academic Search

Summary When suspensions of sycamore cells are cultured in a synthetic medium containing 1.0 mg\\/l 2,4-D and 0.25 mg\\/l kinetin, maximum cell yield is obtained with an initial concentration of 6 per cent sucrose. There is a progressive increase in dry weight per cell, decline in extractive-free weight as a percentage of cell dry weight and increase in lignin content

Marta Carceller; M. R. Davey; M. W. Fowler

1971-01-01

298

L-arabinose fermenting yeast  

DOEpatents

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

2013-02-12

299

The Regulation of Filamentous Growth in Yeast  

PubMed Central

Filamentous growth is a nutrient-regulated growth response that occurs in many fungal species. In pathogens, filamentous growth is critical for host–cell attachment, invasion into tissues, and virulence. The budding yeast Saccharomyces cerevisiae undergoes filamentous growth, which provides a genetically tractable system to study the molecular basis of the response. Filamentous growth is regulated by evolutionarily conserved signaling pathways. One of these pathways is a mitogen activated protein kinase (MAPK) pathway. A remarkable feature of the filamentous growth MAPK pathway is that it is composed of factors that also function in other pathways. An intriguing challenge therefore has been to understand how pathways that share components establish and maintain their identity. Other canonical signaling pathways—rat sarcoma/protein kinase A (RAS/PKA), sucrose nonfermentable (SNF), and target of rapamycin (TOR)—also regulate filamentous growth, which raises the question of how signals from multiple pathways become integrated into a coordinated response. Together, these pathways regulate cell differentiation to the filamentous type, which is characterized by changes in cell adhesion, cell polarity, and cell shape. How these changes are accomplished is also discussed. High-throughput genomics approaches have recently uncovered new connections to filamentous growth regulation. These connections suggest that filamentous growth is a more complex and globally regulated behavior than is currently appreciated, which may help to pave the way for future investigations into this eukaryotic cell differentiation behavior.

Cullen, Paul J.; Sprague, George F.

2012-01-01

300

Analysis of histones from the yeast Saccharomyces carlsbergensis.  

PubMed Central

Basic chromosomal proteins were isolated from the chromatin of the yeast Saccharomyces carlsbergensis by extraction with H2SO4 and were purified by ion-exchange chromatography. Electrophoresis of the purified fraction on acetic acid/urea gels revealed the presence of four main components. These four proteins were identified as histones H2A, H2B, H3 and H4 on the basis of their amino acid composition, molecular weight and solubility properties, all of which are very similar to the corresponding properties of the various histone proteins from other eukaryotic organisms. A fifth basic protein could be isolated from yeast chromatin by extraction with HClO4. The available evidence indicates this protein to be an H1-type histone. Yeast thus appears to contain a complete set of histone proteins which are strongly homologous to the histones occurring in higher eukaryotes. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5.

Pastink, A; Berkhout, T A; Mager, W H; Planta, R J

1979-01-01

301

Influence of cell turgor on sucrose partitioning in potato tuber storage tissues.  

PubMed

Sucrose uptake and partitioning in potato (Solanum tuberosum L.) tuber discs were examined under a range of mannitol and ethylene-glycol concentrations. Mannitol caused the same changes in turgor over a wide range of incubation periods (90 min-6 h), indicating that it did not penetrate the tissue. In comparison, ethylene glycol reduced turgor losses but did not eliminate them, even after 6 h. Between 100 mM and 300 mM mannitol, turgor fell by 350 kPa, compared with 35 kPa in ethylene glycol. Uptake experiments in mannitol alone showed that total sucrose uptake was strongly correlated with both osmotic potential and with turgor potential. In subsequent experiments sucrose uptake and partitioning were examined after 3 h equilibration in 100 mM and 300 mM concentrations of mannitol and ethylene glycol. Total sucrose uptake and the conversion of sucrose to starch were enhanced greatly only at 300 mM mannitol, indicating an effect of turgor, rather than osmotic potential on sucrose partitioning. The inhibitors p-chloromercuribenzenesulfonic acid and carbonylcyanide m-chlorophenylhydrazone (CCCP) both reduced sucrose uptake, but in quite different ways. p-Chloromercuribenzenesulfonic acid reduced total sucrose uptake but did not affect the partitioning of sucrose to starch. By contrast, CCCP inhibited total uptake and virtually eliminated the conversion of sucrose to starch. Despite this, sucrose uptake in the presence of CCCP continued to increase as the mannitol concentration increased, indicating an increase in passive transport at higher mannitol concentrations. Increased sucrose uptake above 400 mM mannitol was shown to be the result of uptake into the free space. The data show that starch synthesis is optimised at low but positive turgors and the relation between sucrose partitioning and the changing diurnal water relations of the tuber are discussed. PMID:24221935

Oparka, K J; Wright, K M

1988-10-01

302

Influence of antioxidant structure on local molecular mobility in amorphous sucrose.  

PubMed

The effect of the antioxidants gallic acid and methyl, propyl, and octyl gallate on the molecular mobility and hydrogen bond network in amorphous sucrose was studied. Solid amorphous sucrose films with and without the addition of antioxidants at a mole ratio of 1:5 (antioxidant/sucrose) were cast from solution onto quartz slides. Local molecular mobility from 0 to 70°C was measured using tryptophan amino acid as a luminescent probe dispersed in the films. Phosphorescence from the tryptophan probe provides spectroscopic characteristics-emission spectrum and lifetime-that are sensitive to changes in molecular mobility induced by the addition of antioxidants. Local molecular mobility detected by tryptophan increased in the following order: sucrose-octyl gallate<sucrose-propyl gallate?sucrose-methyl gallate?sucrose-gallic acid. The antioxidants also modulated the activation energy for matrix motions that quench the tryptophan phosphorescence in a structure-dependent manner. IR measurements as a function of temperature indicated that hydrogen bond strength in these amorphous films followed a rank order (sucrose-methyl gallate>sucrose-gallic acid>sucrose-propyl gallate>sucrose>sucrose-octyl gallate) that was nearly the reverse of that seen in matrix mobility. Analysis of the differential effects of the antioxidants suggests that the presence of the hydroxyl benzoyl head group increased matrix molecular mobility and hydrogen bond strength while the saturated carbon chain decreased mobility and bond strength. The influence of the carboxyl group on matrix properties was comparable to that of the formyloxy group. These results indicate that the addition of specific functional ingredients such as antioxidants may significantly affect the physical properties and consequently functional properties of amorphous edible films in ways that might condition their use. The observed changes are closely related to the chemical structure of the added species. PMID:24239605

Liang, Jun; Corradini, Maria G; Ludescher, Richard D

2014-01-13

303

Plasmid-mediated uptake and metabolism of sucrose by Escherichia coli K-12.  

PubMed Central

The conjugative plasmid pUR400 determines tetracycline resistance and enables cells of Escherichia coli K-12 to utilize sucrose as the sole carbon source. Three types of mutants affecting sucrose metabolism were derived from pUR400. One type lacked a specific transport system (srcA); another lacked sucrose-6-phosphate hydrolase (scrB); and the third, a regulatory mutant, expressed both of these functions constitutively (scrR). In a strain harboring pUR400, both transport and sucrose-6-phosphate hydrolase were inducible by fructose, sucrose, and raffinose; if a scrB mutant was used, fructose was the only inducer. These data suggested that fructose or a derivative acted as an endogenous inducer. Sucrose transport and sucrose-6-phosphate hydrolase were subject to catabolite repression; these two functions were not expressed in an E. coli host (of pUR400) deficient in the adenosine 3-,5'-phosphate receptor protein. Sucrose uptake (apparent Km = 10 microM) was dependent on the scrA gene product and on the phosphoenolpyruvate-dependent sugar:phosphotransferase system (PTS) of the host. The product of sucrose uptake (via group translocation) was identified as sucrose-6-phosphate, phosphorylated at C6 of the glucose moiety. Intracellular sucrose-6-phosphate hydrolase catalyzed the hydrolysis of sucrose-6-phosphate (Km = 0.17 mM), sucrose (Km = 60 mM), and raffinose (Km = 150 mM). The active enzyme was shown to be a dimer of Mr 110,000.

Schmid, K; Schupfner, M; Schmitt, R

1982-01-01

304

Ethanolic fermentation of sucrose, sugarcane juice and molasses by Escherichia coli strain ko11 and Klebsiella oxytoca strain P2  

Microsoft Academic Search

Escherichia coli KO11 and Klebsiella oxytoca P2 recombinants fermented sucrose to ethanol. In minimal medium with 2% or 12% added sucrose KO11 produced 75% and 41%, respectively, of the maximum theoretical yield (0.54g ethanol\\/g sucrose). In Luria-Bertani (LB) broth with up to 8% sucrose, KO11 presented a 94-96% yield and with 12% sucrose, KO11 presented about 69% yield (44.5g ethanol\\/L).

Gervásio P. da Silva; Elza F. de Araújo; Daison O. Silva; Walter V. Guimarães

2005-01-01

305

Antioxidant activities and anticancer effects of red yeast rice grown in the medium containing garlic  

Microsoft Academic Search

The effects of culture time on antioxidant and anticancer activities of red yeast rice-garlic (RYRG) ethanol extracts were\\u000a investigated. RYRG is a product of red yeast rice (Monascus pilosus) grown in medium containing garlic for 0, 2, 4, 6, and 8 weeks. The total phenolic and total flavonoid contents of RYRG extracts\\u000a were increasing with the length of culture periods.

Hye-Jin Park; In-Sook Kim

2011-01-01

306

Global expression studies in baker's yeast reveal target genes for the improvement of industrially-relevant traits: the cases of CAF16 and ORC2  

PubMed Central

Background Recent years have seen a huge growth in the market of industrial yeasts with the need for strains affording better performance or to be used in new applications. Stress tolerance of commercial Saccharomyces cerevisiae yeasts is, without doubt, a trait that needs improving. Such trait is, however, complex, and therefore only in-depth knowledge of their biochemical, physiological and genetic principles can help us to define improvement strategies and to identify the key factors for strain selection. Results We have determined the transcriptional response of commercial baker's yeast cells to both high-sucrose and lean dough by using DNA macroarrays and liquid dough (LD) model system. Cells from compressed yeast blocks display a reciprocal transcription program to that commonly reported for laboratory strains exposed to osmotic stress. This discrepancy likely reflects differences in strain background and/or experimental design. Quite remarkably, we also found that the transcriptional response of starved baker's yeast cells was qualitatively similar in the presence or absence of sucrose in the LD. Nevertheless, there was a set of differentially regulated genes, which might be relevant for cells to adapt to high osmolarity. Consistent with this, overexpression of CAF16 or ORC2, two transcriptional factor-encoding genes included in this group, had positive effects on leavening activity of baker's yeast. Moreover, these effects were more pronounced during freezing and frozen storage of high-sucrose LD. Conclusions Engineering of differentially regulated genes opens the possibility to improve the physiological behavior of baker's yeast cells under stress conditions like those encountered in downstream applications.

2010-01-01

307

Immunoprecipitation and Characterization of Membrane Protein Complexes from Yeast  

ERIC Educational Resources Information Center

In this undergraduate biochemistry laboratory experiment, the vacuolar ATPase protein complex is purified from yeast cell extracts by doing immunoprecipitations under nondenaturing conditions. Immunoprecipitations are performed using monoclonal antibodies to facilitate data interpretation, and subunits are separated on the basis of their molecular…

Parra-Belky, Karlett; McCulloch, Kathryn; Wick, Nicole; Shircliff, Rebecca; Croft, Nicolas; Margalef, Katrina; Brown, Jamie; Crabill, Todd; Jankord, Ryan; Waldo, Eric

2005-01-01

308

Evaluation of liposome populations using a sucrose density gradient centrifugation approach coupled to a continuous flow system.  

PubMed

A method for the evaluation of liposome size populations using sucrose density gradient centrifugation coupled with a continuous flow system is presented. Liposomes, prepared using different methods (rapid solvent evaporation, rehydration, and detergent removal) and modified by assaying several procedures (shaking, sonication and extrusion) were evaluated according to the type of liposome, size and polydispersity. The preparation of liposomes was carried out in the presence of the fluorophor cresyl violet. Extracts of the liposomes were homogenised and centrifuged at 20,073 x g at 4 degrees C for 30 min using sucrose density gradient centrifugation programmes, which provide efficient liposome separation in different sizes. The results of the separation procedure were tested by aspiration of the extracts into a continuous flow system in which the liposomes were disrupted by the continuous mixing with a Triton X-100 solution, prior to their translation to the detector. The luminescence provided by the liberation of the encapsulated fluorophor indicates the distribution of liposomes in each density gradient stage. Three zones were obtained: zone alpha, containing giant unilamellar and multivesicular vesicles, zone beta, with large and medium size liposomes, and zone gamma, which contained small size liposomes. The precision of the separation zones obtained, expressed as RSD%, was lower than 5.6% in all instances. The method provides a relative rapid way to evaluate the liposome polydispersity and size after using conventional methods of synthesis and mechanical modifications. PMID:19481634

Sánchez-López, V; Fernández-Romero, J M; Gómez-Hens, A

2009-07-10

309

Developmental Transition from Enzymatic to Acid Hydrolysis of Sucrose in Acid Limes (Citrus aurantifolia).  

PubMed

The sucrose breakdown mechanisms in juice sacs of acid lime (Citrus aurantifolia [Christm.] Swing.) were investigated throughout fruit development. All three enzymes of sucrose catabolism (sucrose synthase, acid, and alkaline invertase) are present during the initial stages. The activities of these enzymes declined rapidly and disappeared by stage 5 (80% development) but not before vacuolar pH had decreased to approximately 2.5. At this stage, sucrose breakdown occurs by acid hydrolysis. By attaining a vacuolar pH of 2.5 prior to enzyme disappearance, the cell maintains a continuous ability to break down sucrose throughout ontogeny. Thus, acid limes possess a unique and coordinated system for sucrose breakdown that involves both enzymatic and nonenzymatic pathways. PMID:16667241

Echeverria, E

1990-01-01

310

Improvement of fermentation ability under baking-associated stress conditions by altering the POG1 gene expression in baker's yeast.  

PubMed

During the bread-making process, yeast cells are exposed to many types of baking-associated stress. There is thus a demand within the baking industry for yeast strains with high fermentation abilities under these stress conditions. The POG1 gene, encoding a putative transcription factor involved in cell cycle regulation, is a multicopy suppressor of the yeast Saccharomyces cerevisiae E3 ubiquitin ligase Rsp5 mutant. The pog1 mutant is sensitive to various stresses. Our results suggested that the POG1 gene is involved in stress tolerance in yeast cells. In this study, we showed that overexpression of the POG1 gene in baker's yeast conferred increased fermentation ability in high-sucrose-containing dough, which is used for sweet dough baking. Furthermore, deletion of the POG1 gene drastically increased the fermentation ability in bread dough after freeze-thaw stress, which would be a useful characteristic for frozen dough baking. Thus, the engineering of yeast strains to control the POG1 gene expression level would be a novel method for molecular breeding of baker's yeast. PMID:23800735

Sasano, Yu; Haitani, Yutaka; Hashida, Keisuke; Oshiro, Satoshi; Shima, Jun; Takagi, Hiroshi

2013-08-01

311

Hydrothermal decomposition of yeast cells for production of proteins and amino acids.  

PubMed

This study examines hydrothermal decomposition of Baker's yeast cells, used as a model for spent Brewer's yeast waste, into protein and amino acids. The reaction was carried out in a closed batch reactor at various temperatures between 100 and 250 degrees C. The reaction products were separated into water-soluble and solid residue. The results demonstrated that the amount of yeast residue decreased with increasing hydrolysis temperature. After 20 min reaction in water at 250 degrees C, 78% of yeast was decomposed. The highest amount of protein produced was also obtained at this condition and was found to be 0.16 mg/mg dry yeast. The highest amount of amino acids (0.063 mg/mg dry yeast) was found at the lowest temperature tested after 15 min. The hydrolysis product obtained at 200 degrees C was tested as a nutrient source for yeast growth. The growth of yeast cells in the culture medium containing 2 w/v% of this product was comparable to that of the cells grown in the medium containing commercial yeast extract at the same concentration. These results demonstrated the feasibility of using subcritical water to potentially decompose proteinaceous waste such as spent Brewer's yeast while recovering more useful products. PMID:16849032

Lamoolphak, Wiwat; Goto, Motonobu; Sasaki, Mitsuru; Suphantharika, Manop; Muangnapoh, Chirakarn; Prommuag, Chattip; Shotipruk, Artiwan

2006-10-11

312

Optimizing conditions for poly(?-hydroxybutyrate) production by Halomonas boliviensis LC1 in batch culture with sucrose as carbon source  

Microsoft Academic Search

Halomonas boliviensis LC1 is able to accumulate poly(?-hydroxybutyrate) (PHB) under conditions of excess carbon source and depletion of essential\\u000a nutrients. This study was aimed at an efficient production of PHB by growing H. boliviensis to high cell concentrations in batch cultures. The effect of ammonium, phosphate, and yeast extract concentrations on cell\\u000a concentration [cell dry weight (CDW)] and PHB content

Jorge Quillaguamán; Marlene Muñoz; Bo Mattiasson; Rajni Hatti-Kaul

2007-01-01

313

Extracellular Polysaccharides Produced by Yeasts and Yeast-Like Fungi  

NASA Astrophysics Data System (ADS)

Several yeasts and yeast-like fungi are known to produce extracellular polysaccharides. Most of these contain D-mannose, either alone or in combination with other sugars or phosphate. A large chemical and structural variability is found between yeast species and even among different strains. The types of polymers that are synthesized can be chemically characterized as mannans, glucans, phosphoman-nans, galactomannans, glucomannans and glucuronoxylomannans. Despite these differences, almost all of the yeast exopolysaccharides display some sort of biological activity. Some of them have already applications in chemistry, pharmacy, cosmetics or as probiotic. Furthermore, some yeast exopolysaccharides, such as pullulan, exhibit specific physico-chemical and rheological properties, making them useful in a wide range of technical applications. A survey is given here of the production, the characteristics and the application potential of currently well studied yeast extracellular polysaccharides.

van Bogaert, Inge N. A.; de Maeseneire, Sofie L.; Vandamme, Erick J.

314

Sucrose-phosphate synthase steady-state mRNA increases in ripening kiwifruit  

Microsoft Academic Search

Early during fruit ripening in kiwifruit (Actinidia deliciosa var. deliciosa [A. Chev.], C.F. Liang and A.R. Ferguson cv. Hayward), starch is broken down to sucrose and hexose sugars. Concomitantly, sucrose-phosphate synthase (SPS, EC 2.3.1.14) activity measured with saturating substrate increased, suggesting that SPS is induced in response to a higher requirement for sucrose synthesis [29]. A 2584 bp long partial

Georg Langenkämper; Ronnie McHale; Richard C. Gardner; Elspeth MacRae

1998-01-01

315

High yield conversion of sucrose into ethanol by a flocculent Zymomonas sp isolated from sugarcane juice  

Microsoft Academic Search

Summary A flocculentZymomonas sp strain was isolated from fermenting sugarcane juice taking advantage of the motility and ethanol tolerance. The capacity of the new isolate to convert glucose and sucrose into EtOH was investigated. using 200 g\\/l sucrose feed the isolate showed a sucrose uptake and EtOH yield over 3 times higher than those of the test organismZ. mobilis ATCC

Emilio Rodríguez; Danley A. S. Callieri

1986-01-01

316

Preservation of caprine preantral follicle viability after cryopreservation in sucrose and ethylene glycol  

Microsoft Academic Search

Caprine preantral follicles within ovarian fragments were cryopreserved in the absence or presence of 0.5 M sucrose with or without 1 M dimethyl sulfoxide and\\/or 1 M ethylene glycol (EG). After being thawed, they were washed in minimum essential medium with or without 0.3 M sucrose. Histological analysis of follicle integrity immediately after cryopreservation showed consistent beneficial effects of including sucrose in the three

R. R. Santos; T. Tharasanit; J. R. Figueiredo; T. van Haeften; R. van den Hurk

2006-01-01

317

Effects of sucrose, inoculum density, auxins, and aeration volume on ceil growth of Gymnema sylvestre  

Microsoft Academic Search

To improve the cell protocol forCymnema sylvestre, we investigated the influence of initial sucrose concentration, inoculum density, and optimal concentrations of auxins (IBA\\u000a and NAA) in flask cultures, as well as the role of aeration volume in bioreactor cultures. Cell growth was enhanced 9-fold\\u000a when the medium was supplemented with 3% sucrose versus a sucrose-free environment. Increasing the inoculum density

Eun Jung Lee; Mohammad Mobin; Eun Joo Hahn; Kee Yoeup Paek

2006-01-01

318

Modeling sucrose hydrolysis in dilute sulfuric acid solutions at pretreatment conditions for lignocellulosic biomass  

Microsoft Academic Search

Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25g\\/l sucrose with 0.1–2.0% (w\\/w) sulfuric acid concentrations were treated at temperatures of 160–200°C for 3–12min.

Shane Bower; Ranil Wickramasinghe; Nicholas J. Nagle; Daniel J. Schell

2008-01-01

319

Osmotic Dehydration Kinetics of Pumpkin Fruits Using Ternary Solutions of Sodium Chloride and Sucrose  

Microsoft Academic Search

The objective of this work was to obtain experimental data and modeling of osmotic dehydration kinetics of pumpkin fruits (Cucurbita pepo L.) with aqueous NaCl\\/sucrose solutions. For this purpose, effective diffusion coefficients for water, sucrose, and NaCl were calculated by means of a simple model based on Fick's second law. Water loss achieved 80%, sucrose 13%, and NaCl 6% of

L. Mayor; R. Moreira; F. Chenlo; A. M. Sereno

2007-01-01

320

Yeast and Mammalian Metallothioneins Functionally Substitute for Yeast Copper-Zinc Superoxide Dismutase  

NASA Astrophysics Data System (ADS)

Copper-zinc superoxide dismutase catalyzes the disproportionation of superoxide anion to hydrogen peroxide and dioxygen and is thought to play an important role in protecting cells from oxygen toxicity. Saccharomyces cerevisiae strains lacking copper-zinc superoxide dismutase, which is encoded by the SOD1 gene, are sensitive to oxidative stress and exhibit a variety of growth defects including hypersensitivity to dioxygen and to superoxide-generating drugs such as paraquat. We have found that in addition to these known phenotypes, SOD1-deletion strains fail to grow on agar containing the respiratory carbon source lactate. We demonstrate here that expression of the yeast or monkey metallothionein proteins in the presence of copper suppresses the lactate growth defect and some other phenotypes associated with SOD1-deletion strains, indicating that copper metallothioneins substitute for copper-zinc superoxide dismutase in vivo to protect cells from oxygen toxicity. Consistent with these results, we show that yeast metallothionein mRNA levels are dramatically elevated under conditions of oxidative stress. Furthermore, in vitro assays demonstrate that yeast metallothionein, purified or from whole-cell extracts, exhibits copper-dependent antioxidant activity. Taken together, these data suggest that both yeast and mammalian metallothioneins may play a direct role in the cellular defense against oxidative stress by functioning as antioxidants.

Tamai, Katherine T.; Gralla, Edith B.; Ellerby, Lisa M.; Valentine, Joan S.; Thiele, Dennis J.

1993-09-01

321

Antipyretic activity of Nelumbo nucifera rhizome extract.  

PubMed

Antipyretic activity of methanolic extract of rhizome of N. nucifera was studied on normal body temperature and yeast induced pyrexia in rats. Yeast suspension (10 ml/kg, s.c.) increased rectal temperature after 19 hr of administration. The extract, in doses of 200, 300 or 400 mg/kg (po) produced significant dose dependent lowering of normal body temperature and yeast provoked elevation of body temperature in rats. The effect produced was comparable with the standard antipyretic drug, paracetamol (150 mg/kg, i.p.). PMID:8781041

Mukherjee, P K; Das, J; Saha, K; Giri, S N; Pal, M; Saha, B P

1996-03-01

322

Yeast-Hyphal Dimorphism  

Microsoft Academic Search

All fungi have some capacity to grow in two basic morphological forms — spheres and tubes — therefore it could be argued that\\u000a they are all, to some extent, dimorphic. For many filamentous fungi spherical growth may only be expressed during the formation\\u000a of spores and many yeast-like fungi have only the remnants of a true filamentous growth habit. However,

N. A. R. Gow

323

Negative and positive incentive contrast effects with saccharine versus sucrose.  

PubMed

Forty male white rats received 19 sessions of bar press training with sucrose (16% or 4%) as reward followed by a shift from 4% to 16% and from 16% to 4%. Three dependent measures indicated positive and negative contrast effects. In Experiment II, 70 male white rats received 14 sessions of bar press training with (1.2%, 1%, .10%, or .01%) saccharine, and water followed by a shift from 1.2% to .10%, 1.2% to .01%, 1 to .1%, and .10% to .01%. Three of the four measures indicated negative contrast effects. In Experiment III, 40 male white rats experienced 16 sessions of bar press training with 1%, .10%, .05%, or .01% of saccharine followed by an increase from .1%, to 1%, .05% to 1%, and .01% to 1%. Three of the measures indicated positive contrast effects. Confounding inherent in the use of solid food or sucrose did not appear to account for negative and positive incentive contrast effects. PMID:660169

Weinstein, L

1978-04-01

324

Yeast Colony Embedding Method  

PubMed Central

Patterning of different cell types in embryos is a key mechanism in metazoan development. Communities of microorganisms, such as colonies and biofilms also display patterns of cell types. For example, in the yeast S. cerevisiae, sporulated cells and pseudohyphal cells are not uniformly distributed in colonies. The functional importance of patterning and the molecular mechanisms that underlie these patterns are still poorly understood. One challenge with respect to investigating patterns of cell types in fungal colonies is that unlike metazoan tissue, cells in colonies are relatively weakly attached to one another. In particular, fungal colonies do not contain the same extensive level of extracellular matrix found in most tissues . Here we report on a method for embedding and sectioning yeast colonies that reveals the interior patterns of cell types in these colonies. The method can be used to prepare thick sections (0.5 ?) useful for light microscopy and thin sections (0.1 ?) suitable for transmission electron microscopy. Asci and pseudohyphal cells can easily be distinguished from ovoid yeast cells by light microscopy , while the interior structure of these cells can be visualized by EM. The method is based on surrounding colonies with agar, infiltrating them with Spurr's medium, and then sectioning. Colonies with a diameter in the range of 1-2 mm are suitable for this protocol. In addition to visualizing the interior of colonies, the method allows visualization of the region of the colony that invades the underlying agar.

Piccirillo, Sarah; Honigberg, Saul M.

2011-01-01

325

Sugaring the pill. Ethics and uncertainties in the use of sucrose for newborn infants  

PubMed Central

Sucrose is widely used for the management of procedural pain in newborn infants, including capillary blood sampling, venepuncture and vascular cannulation. Multiple randomised controlled trials have demonstrated that sweet-tasting solutions reduce behavioural responses to acute painful stimuli. It has been claimed that sucrose should be a standard of care in neonatal units, and that further placebo-controlled trials of sucrose are unnecessary and unethical. However, recently published neuroscientific studies cast doubt on the analgesic properties of sucrose. We review this new evidence and analyse the philosophical and ethical questions that it raises, including the “problem of other minds”. Sugar may be better understood not as an analgesic, removing or relieving pain, but as a compensating pleasure. There is a need for further research on the mechanism of sucrose’s effect on pain behaviour and on the long-term effects of sucrose treatment. Such trials will require comparison with placebo or with other interventions. Given uncertainty about the benefit of sucrose it may be wise to use alternative analgesics or non-pharmacological interventions where these are available and appropriate. Sucrose may not be the answer to procedural pain in newborns.

Wilkinson, Dominic JC; Savulescu, Julian; Slater, Rebeccah

2012-01-01

326

Sucrose-induced hypocotyl elongation of Arabidopsis seedlings in darkness depends on the presence of gibberellins.  

PubMed

In this study, the effects of sucrose on hypocotyl elongation of Arabidopsis seedlings in light and in dark were investigated. Sucrose suppressed the hypocotyl elongation of Arabidopsis seedlings in light, but stimulated elongation in dark. Application of paclobutrazol (PAC, a gibberellin biosynthesis inhibitor) impaired the effects of sucrose on hypocotyl elongation, suggesting that endogenous GAs is required for sucrose-induced hypocotyl elongation in the dark. Exogenous GA(3) application reversed the repression caused by PAC application, indicating that exogenous GA(3) could substitute, at least partially, for endogenous GAs in sucrose-induced hypocotyl elongation. In addition, we found that GA 3-oxidase 1 (GA3ox1), encoding a key enzyme involved in endogenous bioactive GA biosynthesis, was up-regulated by sucrose in the dark, whereas GIBBERELLIN INSENSITIVE DWARF 1a (AtGID1a), encoding a GA receptor and playing an important role during GAs degradation to DELLA proteins (DELLAs, repressors of GA-induced plant growth), was down-regulated. These results imply that endogenous bioactive GA levels are expected to be enhanced, but the degradation of DELLAs was inhibited by sucrose in dark. Thus, our data suggest that the sucrose-induced hypocotyl elongation in the dark does not result from GA-induced degradation of DELLAs. We conclude that sucrose can stimulate hypocotyl elongation of Arabidopsis seedlings in the dark in a GA-dependent manner. PMID:20430474

Zhang, Yongqiang; Liu, Zhongjuan; Wang, Liguang; Zheng, Sheng; Xie, Jiping; Bi, Yurong

2010-09-15

327

Sucrose increases the activation energy barrier for actin-myosin strong binding.  

PubMed

To determine the mechanism by which sucrose slows in vitro actin sliding velocities, V, we used stopped flow kinetics and a single molecule binding assay, SiMBA. We observed that in the absence of ATP, sucrose (880mM) slowed the rate of actin-myosin (A-M) strong binding by 71±8% with a smaller inhibitory effect observed on spontaneous rigor dissociation (21±3%). Similarly, in the presence of ATP, sucrose slowed strong binding associated with Pi release by 85±9% with a smaller inhibitory effect on ATP-induced A-M dissociation, kT (39±2%). Sucrose had no noticeable effect on any other step in the ATPase reaction. In SiMBA, sucrose had a relatively small effect on the diffusion coefficient for actin fragments (25±2%), and with stopped flow we showed that sucrose increased the activation energy barrier for A-M strong binding by 37±3%, indicating that sucrose inhibits the rate of A-M strong binding by slowing bond formation more than diffusional searching. The inhibitory effects of sucrose on the rate of A-M rigor binding (71%) are comparable in magnitude to sucrose's effects on both V (79±33% decrease) and maximal actin-activated ATPase, kcat, (81±16% decrease), indicating that the rate of A-M strong bond formation significantly influences both kcat and V. PMID:24370736

Jackson, Del R; Webb, Milad; Stewart, Travis J; Phillips, Travis; Carter, Michael; Cremo, Christine R; Baker, Josh E

2014-06-15

328

Sucrose produces withdrawal and dopamine-sensitive reinforcing effects in planarians  

PubMed Central

Sucrose produces physical dependence and reinforcing effects in rats. We hypothesized that similar effects could be demonstrated in planarians, the earliest animal with a centralized nervous system. We used two assays, one that quantifies withdrawal responses during drug absence as a reduction in motility and another that quantifies reinforcing effects using a conditioned place preference (CPP) design. In withdrawal experiments, planarians exposed to sucrose (1%) for 60 min and then tested in water for 5 min displayed reduced motility compared to water controls. Acute or continuous sucrose (1%) exposure did not affect motility. CPP experiments used a biased design to capitalize upon planarians’ natural preference for the dark (pretest, sucrose conditioning in the light, posttest). Planarians conditioned with sucrose (1%) displayed a greater preference shift than sucrose-naïve planarians. Glucose (0.1, 1%), but not the non-digestible disaccharide lactulose (0.1, 1%), also produced a greater preference shift than water-exposed planarians. Development of sucrose-induced CPP was inhibited when sucrose (1%) conditioning was conducted in combination with dopamine receptor antagonists SCH 23390 (1 µM) or sulpiride (1 µM). These results suggest that rewarding and reinforcing effects of sugar are highly conserved across species and that planarians offer an invertebrate model to provide insight into the pharmacological effects of sucrose and related sweeteners.

Zhang, Charlie; Tallarida, Christopher S.; Raffa, Robert B.; Rawls, Scott M.

2014-01-01

329

Thermal decomposition of pyrotechnic mixtures containing sucrose with either potassium chlorate or potassium perchlorate  

Microsoft Academic Search

The thermal behavior of sucrose, KClO3, KClO4, and KClO3+sucrose and KClO4+sucrose mixtures was studied experimentally using differential thermal analysis (DTA) and thermogravimetry (TG). The mixtures (KClO3 or KClO4 with sucrose) are sometimes used as pyrotechnic mixtures in military activities. The results demonstrate that the ignition temperatures for KClO3 and KClO4 are 472 and 592?°C, respectively. On the other hand, DTA-TG

Seied Ghorban Hosseini; Seied Mahdi Pourmortazavi; Seiedeh Somayyeh Hajimirsadeghi

2005-01-01

330

Concentration measurements of sucrose and sugar surfactants solutions by using the 1H NMR ERETIC method.  

PubMed

The ERETIC method has been used to determine precise concentrations of aqueous solutions of sucrose and sugar surfactants, namely octyl glucoside and fatty acid sucrose esters by (1)H NMR spectroscopy. The effects of NMR tuning, acquisition parameters, and spectrum processing on the measurement have been assessed in these particular cases. The linearity upholds over the whole concentration range, with both sucrose and octyl glucoside, whatever the physicochemical phenomena occurring, either an increasing viscosity or the micellization of the surfactant. For sucrose solutions, an accuracy of 2% is measured for concentrations between 0.1 and 200 mmol/L, which is consistent with literature data. PMID:16697992

Molinier, Valérie; Fenet, Bernard; Fitremann, Juliette; Bouchu, Alain; Queneau, Yves

2006-08-14

331

Momordica charantia maintains normal glucose levels and lipid profiles and prevents oxidative stress in diabetic rats subjected to chronic sucrose load.  

PubMed

Momordica charantia L., commonly known as bitter gourd, is used as a vegetable by the Asian community in Africa. It is frequently used as an antidiabetic herb for the management of the disease in the Ayurvedic system of medicine. The present study was aimed at evaluating the effects of M. charantia on glucose level, lipid profiles, and oxidative stress in diabetic rats subjected to a sucrose load. Five normal rats and 20 diabetic rats (diabetes induced by injecting alloxan monohydrate) were used for the experiment. Diabetic rats were divided into four groups: three experimental groups that received sucrose (4 g/kg of body weight) plus graded doses of M. charantia extract and a diabetic control group that received only sucrose (4 g/kg of body weight). Normal rats were used as the normal control group and received only sucrose (4 kg/kg of body weight). The experiment was run for 30 days, after which rats were bled to assay blood glucose, lipid profiles, and thiobarbituric acid-reactive substances and reduced glutathione. After this, all treatments were terminated. Rats in the normal control group, diabetic control group, and experimental group 3 were subjected to observation for 30 days and were bled on day 31 to assay parameters as stated above. Results indicated that M. charantia maintained the normal glucose levels in all experimental groups, reduced triglyceride and low-density lipoprotein levels, and increased high-density lipoprotein levels. It also improved the antioxidant status, indicated by low levels of thiobarbituric acid-reactive substances and normal levels of reduced glutathione. Rats reverted to diabetic conditions and were found to be under oxidative stress after termination of treatment. This study concludes that M. charantia maintains the normal glucose level, lipid profiles, and antioxidant condition in diabetic rats against the sucrose load. PMID:20521977

Chaturvedi, Padmaja; George, Saramma

2010-06-01

332

Sucrose induces expression of the sorbitol-6-phosphate dehydrogenase gene in source leaves of loquat.  

PubMed

Rosaceae fruit trees use sorbitol and sucrose as translocating sugars and the sorbitol-to-sucrose ratio in source leaves determines apple fruit quality. Here, we investigate the effects of sugars on the expression of genes encoding key photosynthetic enzymes, including sorbitol-6-phosphate dehydrogenase (S6PDH, EC 1.1.1.200), sucrose phosphate synthase (SPS, EC 2.4.1.14), and ADP-glucose pyrophosphorylase (ADPGPPase, EC 2.7.7.27) to understand the sugar-signaling mechanism in Rosaceae fruit trees. Mature leaf-petiole cuttings of loquat (Eriobotrya japonica Lindl. cv. Mogi) were supplied with a water, sorbitol or sucrose solution for 2?days at 20°C. The relative levels of the transcripts were analyzed by real-time polymerase chain reaction (PCR). S6PDH transcription was decreased by sorbitol but drastically increased by sucrose. SPS and ADPGPPase large subunit transcription were decreased by sucrose and sorbitol. The simultaneous application of sorbitol and sucrose revealed that S6PDH transcription increased in a dose-dependent manner with sucrose. These results show that both sorbitol and sucrose work as signaling molecules in source organs of Rosaceae fruit trees. These trees have mechanisms to positively keep sorbitol as the dominant translocating sugar, suggesting that sorbitol plays an important role in their survival strategy. Effects of various sugars on S6PDH expression were investigated. Palatinose, a sucrose analog, increased S6PDH transcription much more drastically than sucrose. Mannose and 3-O-methylglucose, glucose analogs, also increased S6PDH transcription; however, glucose did not. Models of sugar signaling in source organs of Rosaceae fruit trees are discussed. PMID:24102486

Suzuki, Yasuo; Dandekar, Abhaya M

2014-03-01

333

Molecular characterization and functional analysis of sucrose-cleaving enzymes in carrot (Daucus carota L.).  

PubMed

The amount of carbon transported into storage organs of crop plants to a large degree determines crop yield. The role of sucrose-cleaving enzymes in this process is not clear and it is the main goal of our work to tackle this question. Sucrose cleavage is catalysed either by invertase or sucrose synthase both of which exist in several isoforms with different subcellular locations. Carrot (Daucus carota L.) contains three major isoenzymes of acid invertase, which either accumulate as soluble polypeptides in the vacuole (isoenzymes I and II) or are ionically bound to the cell wall. Carrot sucrose synthase is thought to be a cytoplasmic enzyme encoded by two genes. cDNA clones have been isolated and characterized for cell wall invertase, for isoenzymes I and II of vacuolar invertase, and for sucrose synthase. Gene-specific fragments of these clones were used to determine the steady-state levels of transcripts in the prominent sink and source organs of developing carrot plants. The expression patterns of each gene were different and were organ- and development-specific. Developing tap roots contained only transcripts for isoenzyme II of vacuolar invertase and sucrose synthase. The source/sink balance of these plants was manipulated and only the expression of these two genes was markedly altered, indicating their importance in sucrose partitioning. Based on these results, a model is proposed for sucrose partitioning in carrot plants with developing tap roots in which sucrose synthase regulates sucrose utilization, whereas isoenzyme II of vacuolar invertase controls sucrose storage and sugar composition. PMID:21245247

Sturm, A

1996-08-01

334

Electrogenicity, pH-Dependence, and Stoichiometry of the Proton-Sucrose Symport  

PubMed Central

The electrogenicity, pH-dependence, and stoichiometry of the proton-sucrose symport were examined in plasma membrane vesicles isolated from sugar beet (Beta vulgaris L. cv Great Western) leaves. Symport mediated sucrose transport was electrogenic as demonstrated by the effect of membrane potential on ?pH-dependent flux. In the absence of significant charge compensation, a low rate of sucrose transport was observed. When membrane potential was clamped at zero with symmetric potassium concentrations and valinomycin, the rate of sucrose flux was stimulated fourfold. In the presence of a negative membrane potential, transport increased six-fold. These results are consistent with electrogenic sucrose transport which results in a net flux of positive charge into the vesicles. The effect of membrane potential on the kinetics of sucrose transport was on Vmax only with no apparent change in Km. Sucrose transport rates driven by membrane potential only, i.e. in the absence of ?pH, were comparable to ?pH-driven flux. Both membrane potential and ?pH-driven sucrose transport were used to examine proton binding to the symport and the apparent Km for H+ was 0.7 micromolar. The kinetics of sucrose transport as a function of proton concentration exhibited a simple hyperbolic relationship. This observation is consistent with kinetic models of ion-cotransport systems when the stoichiometry of the system, ion:substrate, is 1:1. Quantitative measurements of proton and sucrose fluxes through the symport support a 1:1 stoichiometry. The biochemical details of protoncoupled sucrose transport reported here provide further evidence in support of the chemiosmotic hypothesis of nutrient transport across the plant cell plasma membrane.

Bush, Daniel R.

1990-01-01

335

Quantitative estimation of transcellular and paracellular pathways of biliary sucrose in isolated perfused rat liver.  

PubMed Central

A method was developed to estimate the relative contributions of paracellular and transcellular pathways to the total biliary clearance of sucrose in isolated perfused rat liver. When livers were perfused with a sucrose-containing medium (1 mM), biliary sucrose concentration reached an equilibrium of 165 +/- 27 microM within 10 min, without further significant change up to 40 min. After removal of sucrose from the perfusate, the decrease of the sucrose concentration in bile was found to obey biphasic first-order kinetics, showing a rapid initial decrease (half-life 3.3 +/- 0.5 min) and then a slower decrease (half-life 29.4 +/- 5.7 min). Both phases of decrease were further characterized. Pretreating rats with the cholestatic agents alpha-naphthyl isothiocyanate (ANIT), oestradiol valerate (OV) and colchicine increased the biliary equilibrium concentration and decreased the half-life of the fast phase of the biliary sucrose elimination. The slow phase was unaffected in the livers of ANIT- and OV-treated rats. The slow phase of biliary sucrose efflux was sensitive to colchicine treatment. A close correlation was observed between the slow-phase fraction of the biliary sucrose and the corresponding sucrose content of the liver. By quantitative analysis of the efflux kinetics the relative contribution of the paracellular pathway to the biliary clearance of sucrose was estimated to be 83 +/- 2% in control livers, which increased to about 90% in livers of pretreated animals. These results are important in view of the use of sucrose in evaluating the paracellular-pathway permeability in intra- and extra-hepatic cholestasis.

Jaeschke, H; Krell, H; Pfaff, E

1987-01-01

336

Virulence of Streptococcus mutans: comparison of the effects of a coupling sugar and sucrose on certain metabolic activities and cariogenicity.  

PubMed Central

A coupling sugar preparation (sucrose-free [CSSF]), which contains a mixture of sugars, oligosaccharides, and oligosaccharides terminated at the reducing end by sucrose, served as a substrate for growth and acid production by Streptococcus mutans 6715. However, CSSF was a poor substrate for cellular aggregation, glucosyltransferase activity, plaque formation, and adherence of cells to glass surfaces. In the presence of sucrose, CSSF inhibited glucosyltransfer activity and adherence of cells. The substitution of CSSF for sucrose in a rat diet significantly reduced caries score. Furthermore, rats fed diets containing sucrose and CSSF had significantly fewer carious lesions than did rats fed a sucrose diet.

Ikeda, T; Shiota, T; McGhee, J R; Otake, S; Michalek, S M; Ochiai, K; Hirasawa, M; Sugimoto, K

1978-01-01

337

A fraction derived from brewer's yeast inhibits cholesterol synthesis by rat liver preparations in vitro.  

PubMed

Brewer's yeast was grown on a defined medium containing tracer 51Cr with or without added chromium. The two batches of yeast contained 10 microgram/g (high-Cr) or 80 ng/g (low-Cr). Extracts were prepared and fractionated. A third batch of yeast (third batch) was grown with added Cr, and fractionated. Rats were reared on either rat cubes (normal diet) or on a low-Cr diet (low-Cr), or on rat cubes with added cholestyramine (cholestyramine diet). Preparations of rat liver, both cell-free and intact hepatocytes, incorporated acetate-carbon into fatty acids and cholesterol. These processes were inhibited by a yeast fraction containing small, neutral, water-soluble compounds. The degree of inhibition was the same whether the liver came from normal rats or rats fed on the low-Cr diet. Similarly the inhibitory effect was found with identical amounts of extracts from low- or high-Cr yeasts. Therefore, Cr compounds do not appear to account for the inhibitory effects of brewer's yeast. Use of other substrates indicated that the site of inhibition of sterol synthesis was apparently between acetyl-CoA and mevalonate. One inhibitory substance was isolated from yeast and was found to be nicotinamide riboside. This may have been produced from NAD(P) during the preparation of yeast extracts, and it may be produced from dietary yeast supplements during digestion in vivo. Nicotinamide riboside may be partly responsible for the reported effects of yeast supplements on plasma lipids in humans. PMID:2043605

Holdsworth, E S; Kaufman, D V; Neville, E

1991-03-01

338

Identification of sucrose synthase as an actin-binding protein  

NASA Technical Reports Server (NTRS)

Several lines of evidence indicate that sucrose synthase (SuSy) binds both G- and F-actin: (i) presence of SuSy in the Triton X-100-insoluble fraction of microsomal membranes (i.e. crude cytoskeleton fraction); (ii) co-immunoprecipitation of actin with anti-SuSy monoclonal antibodies; (iii) association of SuSy with in situ phalloidin-stabilized F-actin filaments; and (iv) direct binding to F-actin, polymerized in vitro. Aldolase, well known to interact with F-actin, interfered with binding of SuSy, suggesting that a common or overlapping binding site may be involved. We postulate that some of the soluble SuSy in the cytosol may be associated with the actin cytoskeleton in vivo.

Winter, H.; Huber, J. L.; Huber, S. C.; Davies, E. (Principal Investigator)

1998-01-01

339

The Structure of a Cyanobacterial Sucrose-Phosphatase Reveals the Sugar Tongs That Release Free Sucrose in the CellW?  

PubMed Central

Sucrose-phosphatase (SPP) catalyzes the final step in the pathway of sucrose biosynthesis in both plants and cyanobacteria, and the SPPs from these two groups of organisms are closely related. We have crystallized the enzyme from the cyanobacterium Synechocystis sp PCC 6803 and determined its crystal structure alone and in complex with various ligands. The protein consists of a core domain containing the catalytic site and a smaller cap domain that contains a glucose binding site. Two flexible hinge loops link the two domains, forming a structure that resembles a pair of sugar tongs. The glucose binding site plays a major role in determining the enzyme's remarkable substrate specificity and is also important for its inhibition by sucrose and glucose. It is proposed that the catalytic reaction is initiated by nucleophilic attack on the substrate by Asp9 and involves formation of a covalent phospho-Asp9-enzyme intermediate. From modeling based on the SPP structure, we predict that the noncatalytic SPP-like domain of the Synechocystis sucrose-phosphate synthase could bind sucrose-6F-phosphate and propose that this domain might be involved in metabolite channeling between the last two enzymes in the pathway of sucrose synthesis.

Fieulaine, Sonia; Lunn, John E.; Borel, Franck; Ferrer, Jean-Luc

2005-01-01

340

Shallow-burial dolomite cement: a major component of many ancient sucrosic dolomites  

Microsoft Academic Search

Dolomite cement is a significant and widespread component of Phanerozoic sucrosic dolomites. Cements in dolomites that were never deeply buried are limpid, have planar faces (non-saddle forms), often distinct zonation in cathodoluminescence and form syntaxial overgrowths on crystals facing pores. Five samples of sucrosic dolomites, interpreted as having had mostly lime- mudstone or wackestone precursors in four carbonate aquifers, provide

Philip W. Choquette; Eric E. Hiatt

2008-01-01

341

Acrosomal status and mitochondrial activity of human spermatozoa vitrified with sucrose  

Microsoft Academic Search

This study investigates the ability of sucrose to protect spermatozoa against mitochondrial damage, artificial cryoinduction of capacitation, and acrosome reaction. Spermatozoa were isolated using the swim-up procedure performed using three different media: (a) human tubal fluid (HTF, control) medium; (b) HTF with 1% human serum albumin (HSA); and (c) HTF with 1% HSA and 0.25 M sucrose. From each group,

E Isachenko; V Isachenko; J M Weiss; R Kreienberg; I I Katkov; M Schulz; A G-M I Lulat; M J Risopatron; R Sanchez

2008-01-01

342

Radiation-induced eco-compatible sulfonated starch\\/acrylic acid graft copolymers for sucrose hydrolysis  

Microsoft Academic Search

Radiation-induced graft-copolymers capable of hosting sulfonic groups and having more effective catalytic activity towards sucrose hydrolysis were prepared. Acrylic acid monomer (AA) was copolymerized with sulfonated starch (SS) at different compositions using ionizing radiation. Swelling behavior of the prepared copolymers at different environmental conditions was studied as well as thermal stability. The hydrolysis of sucrose to glucose and fructose by

H. A. Abd El-Rehim; D. A. Diaa

343

Impact of Weighting Agents and Sucrose on Gravitational Separation of Beverage Emulsions  

Microsoft Academic Search

The influence of weighting agents and sucrose on gravitational separation in 1 wt % oil-in-water emulsions was studied by measuring changes in the intensity of backscattered light from the emulsions with height. Emulsions with different droplet densities were prepared by mixing weighting agents (brominated vegetable oil (BVO), ester gum (EG), damar gum (DG), or sucrose acetate isobutyrate (SAIB)) with soybean

Ratjika Chanamai; D. Julian McClements

2000-01-01

344

Repeated Cocaine Experience Facilitates Sucrose-Reinforced Operant Responding in Enriched and Isolated Rats  

ERIC Educational Resources Information Center

The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30)…

Klein, Emily D.; Gehrke, Brenda J.; Green, Thomas A.; Zentall, Thomas R.; Bardo, Michael T.

2007-01-01

345

Effects of shifts in sucrose and saccharine concentrations on licking behavior in the rat  

Microsoft Academic Search

4 experiments studied the effects of shifts in concentration of liquid reinforcers on licking behavior of 92 adult rats. Depressed performance (relative to control groups) accompanied a shift of 32-4% sucrose solutions, but no shift in saccharine concentrations. Various bases for this disparity were investigated, including type and levels of deprivation. Depression in licking results from shifts in sucrose concentration,

John R. Vogel; Peter J. Mikulka; Norman E. Spear

1968-01-01

346

Modification of soybean sucrose synthase by S-thiolation with ENOD40 peptide A.  

PubMed

The gene ENOD40 is expressed at an early stage of root nodule organogenesis and has been postulated to play a central regulatory role in the Rhizobium-legume interaction. In vitro translation of soybean ENOD40 mRNA showed that the gene encodes two peptides of 12 and 24aa residues (peptides A and B) that bind to sucrose synthase. Here we show that the small Cys-containing peptide A binds to sucrose synthase by disulfide bond formation, which may represent a novel form of posttranslational modification of this important metabolic enzyme. Assays using nanomolar concentrations of peptide A revealed that the monomeric reduced form of this peptide binds to purified sucrose synthase. Using a cysteinyl capture strategy combined with MALDI-TOF MS analysis we identified the Cys residue C264 of soybean sucrose synthase as the binding site of peptide A. Modification of sucrose synthase with ENOD40 peptide A activates sucrose cleavage activity whereas the synthesis activity of the enzyme is unaffected. The results are discussed in relation to the role of sucrose synthase in the control of sucrose utilization in nitrogen-fixing nodules. PMID:15541370

Röhrig, Horst; John, Michael; Schmidt, Jürgen

2004-12-17

347

Effects of sucrose on photosynthesis and phosphoenolpyruvate carboxylase activity of in vitro cultured strawberry plantlets  

Microsoft Academic Search

Photosynthesis and phosphoenolpyruvate carboxylase activity were investigated in 5, 10 and 28 day-old micropropagated strawberry plantlets (Fragaria x ananassa Duch. cv Kent) rooted in vitro with different levels of sucrose (0, 1, 3 and 5%) on cellulose plugs (Sorbarods). The photosynthetic capability was influenced by the level of sucrose in the culture medium with the largest rates of photosynthesis corresponding

Chafik Hdider; Yves Desjardins

1994-01-01

348

Pursuing the Pavlovian Contributions to Induction in Rats Responding for 1% Sucrose Reinforcement  

ERIC Educational Resources Information Center

The present study investigated whether Pavlovian conditioning contributes, in the form of the response operandum serving as a conditioned stimulus, to the increase in the rate of response for 1% liquid-sucrose reinforcement when food-pellet reinforcement is upcoming. Rats were exposed to conditions in which sign tracking for 1% sucrose was…

Weatherly, Jeffrey N.; Huls, Amber; Kulland, Ashley

2007-01-01

349

Diminished Reactivity of Postmature Human Infants to Sucrose Compared with Term Infants.  

ERIC Educational Resources Information Center

This study of healthy 39-week-old infants, so-called term infants, and chronically stressed 42-week-old infants, so-called postmature infants, showed that sucrose was extremely effective in calming term infants but less effective in calming postmature infants. Results supported the hypothesis that sucrose engages an opioid system in infants. (BG)

Smith, Barbara A.; And Others

1992-01-01

350

Sucrose regulation of ADP-glucose pyrophosphorylase subunit genes transcript levels in leaves and fruits  

NASA Technical Reports Server (NTRS)

ADP-glucose pyrophosphorylase (AGPase, EC2.7.7.27) is a key regulatory enzyme in starch biosynthesis. The enzyme is a heterotetramer with two S and two B subunits. In tomato, there are three multiple forms of the S subunit gene. Agp S1, S2 and B are highly expressed in fruit from 10 to 25 days after anthesis. Agp S3 is only weakly expressed in fruit. Sucrose significantly elevates expression of Agp S1, S2 and B in both leaves and fruits. Agp S1 exhibits the highest degree of regulation by sucrose. In fact, sucrose may be required for Agp S1 expression. For excised leaves incubated in water, no transcripts for Agp S1 could be detected in the absence of sucrose, whereas it took up to 16 h in water before transcripts were no longer detectable for Agp S2 and B. Neither Agp S3 nor the tubulin gene is affected by sucrose, demonstrating that this response is specifically regulated by a carbohydrate metabolic signal, and is not due to a general increase in metabolism caused by sucrose treatment. Truncated versions of the promoter for Agp S1 indicate that a specific region 1.3-3.0 kb upstream from the transcription site is responsible for sucrose sensitivity. This region of the S1 promoter contains several cis-acting elements present in the promoters of other genes that are also regulated by sucrose. c2002 Elsevier Science Ireland Ltd. All rights reserved.

Li, Xiangyang; Xing, Jinpeng; Gianfagna, Thomas J.; Janes, Harry W.

2002-01-01

351

Fructansucrase enzymes and sucrose analogues: A new approach for the synthesis of unique fructo-oligosaccharides  

Microsoft Academic Search

Fructansucrase enzymes of lactic acid bacteria use the cheap compound sucrose (Glc-Fru) to synthesize a variety of poly- and oligosaccharide products. Recently, it has been shown that a variety of sucrose analogues (e.g. Gal-Fru, Man-Fru) can be efficiently synthesized. This has exciting potential for the development of novel (fructo) oligosaccharide derivatives.

S. Kralj; K. Buchholz; L. Dijkhuizen; J. Seibel

2008-01-01

352

Nitroglycerin and Sucrose Permeability as Quality Markers for Reconstructed Human Epidermis  

Microsoft Academic Search

In order to evaluate the epidermal permeability barrier of in vitro reconstructed epidermis, the penetration of nitroglycerin (NG) and sucrose were measured across human keratinocytes cultured at the air-liquid interface, using de-epidermized dermis (DED) as a substrate. In the presence of reconstructed epidermis on top of DED the penetration rate of sucrose is about 100 times and that of NG

Maria Ponec; Paulette J. J. Wauben-Penris; Anita Burger; Johanna Kempenaar; Harry E. Boddé

1990-01-01

353

DNA Replication of the Parvovirus Kilham Rat Virus. I. Characterization of Intracellular Forms of Viral DNA Extracted by Guanidine Hydrochloride.  

National Technical Information Service (NTIS)

The following experimental procedures are described: infection of rat kidney cell cultures with Kilham rat virus (KRV); labeling and extraction of DNA; sucrose density gradient sedimentation; digestion by S sub 1 nuclease; and chromatography of DNA on ben...

A. T. Li G. Lavelle R. W. Tennant

1977-01-01

354

STUDIES ON THE PERMEABILITY OF CALF THYMUS NUCLEI ISOLATED IN SUCROSE  

PubMed Central

A study of the permeability of calf thymus nuclei isolated in sucrose was carried out with sucrose-14C, glycerol-14C, and carboxydextran-14C (molecular weight, 60,000–90,000). The results indicate that the nuclei are very permeable to both sucrose and glycerol but they exclude the carboxydextran. Results obtained with other low molecular weight non-electrolytes (malonamide-14C, erythritol-14C, D-arabinose-14C, and D-mannitol-14C) are in agreement with the view that the nuclei are freely permeable to these molecular species. A sucrose-impermeable space is also present in these preparations and it has been attributed to the presence of intact cells. The high permeability of nuclei to sucrose was confirmed with Ficoll-separated preparations. The possibility of the presence of a substantial particulate space that allows the penetration of dextran cannot be excluded by these experiments, and this space may correspond to damaged nuclei.

Kodama, Robert M.; Tedeschi, Henry

1968-01-01

355

Yeast interactions and wine flavour  

Microsoft Academic Search

Wine is the product of complex interactions between fungi, yeasts and bacteria that commence in the vineyard and continue throughout the fermentation process until packaging. Although grape cultivar and cultivation provide the foundations of wine flavour, microorganisms, especially yeasts, impact on the subtlety and individuality of the flavour response. Consequently, it is important to identify and understand the ecological interactions

Graham H. Fleet

2003-01-01

356

Yeast as a screening tool  

Microsoft Academic Search

The versatile genetic malleability of yeast, and the high degree of conservation between its cellular processes and those of human cells, have made it the model of choice for pioneering research in molecular and cell biology over the past four decades. These character- istics of yeast, taken together with technical advan- tages such as simple growth conditions, rapid cell division

Alcide Barberis; Tea Gunde; Catherine Berset; Stephan Audetat; Urs Lüthi

2005-01-01

357

Monitoring polyglutamine toxicity in yeast.  

PubMed

Experiments in yeast have significantly contributed to our understanding of general aspects of biochemistry, genetics, and cell biology. Yeast models have also delivered deep insights in to the molecular mechanism underpinning human diseases, including neurodegenerative diseases. Many neurodegenerative diseases are associated with the conversion of a protein from a normal and benign conformation into a disease-associated and toxic conformation - a process called protein misfolding. The misfolding of proteins with abnormally expanded polyglutamine (polyQ) regions causes several neurodegenerative diseases, such as Huntington's disease and the Spinocerebellar Ataxias. Yeast cells expressing polyQ expansion proteins recapitulate polyQ length-dependent aggregation and toxicity, which are hallmarks of all polyQ-expansion diseases. The identification of modifiers of polyQ toxicity in yeast revealed molecular mechanisms and cellular pathways that contribute to polyQ toxicity. Notably, several of these findings in yeast were reproduced in other model organisms and in human patients, indicating the validity of the yeast polyQ model. Here, we describe different expression systems for polyQ-expansion proteins in yeast and we outline experimental protocols to reliably and quantitatively monitor polyQ toxicity in yeast. PMID:21144902

Duennwald, Martin L

2011-03-01

358

Over-expression of the yeast multifunctional arom protein.  

PubMed

The pentafunctional arom protein of Saccharomyces cerevisiae is encoded by the ARO1 gene. Substantial elevation of the levels of the arom protein (25-fold) was achieved in yeast using a vector that exploited the ubiquitin-fusion cleavage system of yeast. However, attempts to express the N-terminal 3-dehydroquinate synthase domain (E1) or the internal 3-dehydroquinase domain (E2) using the same system did not succeed. The yeast arom protein was successfully purified from the over-expressing transformant, and was found to possess all five enzymatic activities in a ratio similar to that observed in crude cell extracts. The purified material consisted mainly of a polypeptide that co-migrated in SDS-PAGE with intact arom proteins from other species. PMID:8268222

Graham, L D; Gillies, F M; Coggins, J R

1993-12-14

359

A new method for rapid screening of ester-producing yeasts using in situ HS-SPME.  

PubMed

The selection of ester-producing yeasts is difficult because these molecules evaporate quickly, are extremely unstable and may be missed during analytical manipulation. We propose an easy, fast and efficient headspace-SPME method for screening of ester-producing yeasts directly at the extraction vials (in situ HS-SPME). PMID:24814753

Garavaglia, Juliano; Habekost, Andressa; Bjerk, Thiago Rodrigues; de Souza Schneider, Rosana de Cassia; Welke, Juliane Elisa; Zini, Cláudia Alcaraz; Valente, Patricia

2014-08-01

360

Stimulation of Fermentation and Yeast-like Morphogenesis in Mucor rouxii by Phenethyl Alcohol  

PubMed Central

The germination of fungal spores into hyphae was inhibited by concentrations of phenethyl alcohol (PEA) from 0.05 to 0.3%. Spores of Mucor formed budding spherical cells instead of filaments. These cells were abundant in cultures of Mucor rouxii at 0.22% PEA, provided that the carbon source was a hexose at 2 to 5%. Morphology was filamentous with xylose, maltose, sucrose, or a mixture of amino acids. Removal of PEA resulted in the conversion of yeast-like cells into hyphae. PEA did not inhibit biosynthesis of cytochromes or oxygen uptake, but it stimulated CO2 and ethyl alcohol production. PEA had no effect on the rate of oxygen uptake, but it inhibited the oxidative-phosphorylation activity of mitochondria. These results suggested that growth inhibition by PEA could result from uncoupling of oxidative phosphorylation and that, in Mucor, yeast-like morphology and fermentation were linked. Images

Terenzi, H. F.; Storck, R.

1969-01-01

361

Dissecting ribosome assembly and transport in budding yeast.  

PubMed

Construction of the eukaryotic ribosome begins in the nucleolus and requires >300 evolutionarily conserved nonribosomal trans-acting factors, which transiently associate with preribosomal subunits at distinct assembly stages. A subset of trans-acting and transport factors passage assembled preribosomal subunits in a functionally inactive state through the nuclear pore complexes (NPC) into the cytoplasm, where they undergo final maturation before initiating translation. Here, we summarize the repertoire of tools developed in the model organism budding yeast that are spearheading the functional analyses of trans-acting factors involved in the assembly and intracellular transport of preribosomal subunits. We elaborate on different GFP-tagged ribosomal protein reporters and a pre-rRNA reporter that reliably monitors the movement of preribosomal particles from the nucleolus to cytoplasm. We discuss the powerful yeast heterokaryon assay, which can be employed to uncover shuttling trans-acting factors that need to accompany preribosomal subunits to the cytoplasm to be released prior to initiating translation. Moreover, we present two biochemical approaches, namely sucrose gradient analyses and tandem affinity purification, that are rapidly facilitating the uncovering of regulatory processes that control the compositional dynamics of trans-acting factors on maturing preribosomal particles. Altogether, these approaches when combined with traditional analytical biochemistry, targeted proteomics and structural methodologies, will contribute to the dissection of the assembly and intracellular transport of preribosomal subunits, as well as other macromolecular assemblies that influence diverse biological pathways. PMID:24857742

Altvater, Martin; Schütz, Sabina; Chang, Yiming; Panse, Vikram Govind

2014-01-01

362

Ultrasonic velocity assay of extracellular invertase in living yeasts.  

PubMed

The use of a low-intensity ultrasonic technique (noninvasive, nondestructive, on-line, and able to assess opaque samples) to monitor the kinetics of invertase hydrolysis is presented. Adiabatic compressibility has been shown to be sensitive to sugar species: ultrasonic velocity increasing as saccharose is transformed into glucose and fructose. The influence of initial sucrose mass concentration (2-60%), temperature (25-55 degrees C), pH (3.5-6.5), and number of microorganisms (10(5)-10(9) yeasts/ml) on the reaction rate, catalyzed by the extracellular invertases of intact Saccharomyces cerevisiae cells, has been measured. The results were proven to be in strict agreement with the optimal kinetic parameters of the enzyme. Ultrasonic velocity variations are explained in terms of changes of the solute concentrations in the mixture water-saccharose-glucose/fructose and calculated from the velocity of ultrasound in the corresponding pure sugar solutions. A linear relationship between the initial rate of ultrasonic velocity and the number of yeasts (enzymes) is pointed out. PMID:18835377

Resa, Pablo; Elvira, Luis; Sierra, Carlos; Espinosa, Francisco Montero de

2009-01-01

363

Modelling the yeast interactome.  

PubMed

The topology behind biological interaction networks has been studied for over a decade. Yet, there is no definite agreement on the theoretical models which best describe protein-protein interaction (PPI) networks. Such models are critical to quantifying the significance of any empirical observation regarding those networks. Here, we perform a comprehensive analysis of yeast PPI networks in order to gain insights into their topology and its dependency on interaction-screening technology. We find that: (1) interaction-detection technology has little effect on the topology of PPI networks; (2) topology of these interaction networks differs in organisms with different cellular complexity (human and yeast); (3) clear topological difference is present between PPI networks, their functional sub-modules, and their inter-functional "linkers"; (4) high confidence PPI networks have more "geometrical" topology compared to predicted, incomplete, or noisy PPI networks; and (5) inter-functional "linker" proteins serve as mediators in signal transduction, transport, regulation and organisational cellular processes. PMID:24589662

Janji?, Vuk; Sharan, Roded; Pržulj, Nataša

2014-01-01

364

Red yeast rice for dysipidemia.  

PubMed

Red yeast rice is an ancient Chinese food product that contains monacolins, chemical substances that are similar to statins in their mechanisms of action and lipid lowering properties. Several studies have found red yeast rice to be moderately effective at improving the lipid profile, particularly for lowering the low-density lipoprotein cholesterol levels. One large randomized controlled study from China found that red yeast rice significantly improved risk of major adverse cardiovascular events and overall survival in patients following myocardial infarction. Thus, red yeast rice is a potentially useful over-the-counter cholesterol-lowering agent. However, many red yeast rice formulations are non-standardized and unregulated food supplements, and there is a need for further research and regulation of production. PMID:24003656

Shamim, Shariq; Al Badarin, Firas J; DiNicolantonio, James J; Lavie, Carl J; O'Keefe, James H

2013-01-01

365

Programmed nuclear destruction in yeast  

PubMed Central

Studies of the budding yeast Saccharomyces cerevisiae have provided many of the most important insights into the mechanisms of autophagy, which are common to all eukaryotes. However, investigation of yeast self-destruction pathways, including autophagy and programmed cell death, has been almost exclusively restricted to cells undergoing vegetative growth, leaving very little exploration of their functions during developmental transitions in the yeast life cycle. We have recently discovered that whole nuclei are subject to programmed destruction during yeast gametogenesis. Programmed nuclear destruction (PND) possesses characteristics of apoptosis in the form of DNA cleavage by endonuclease G, and involves bulk protein turnover through an unusual autophagic pathway involving lysis of the vacuole rather than delivery of components to it through macroautophagy. We thus illuminate an example of developmentally programmed cellular “self-eating” in yeast, which is associated with the rupture of a lytic organelle, reminiscent of programmed cell death mechanisms in plants and animals.

Eastwood, Michael D.; Cheung, Sally W.T.; Meneghini, Marc D.

2013-01-01

366

Biochemical Mechanism for Regulation of Sucrose Accumulation in Leaves during Photosynthesis 1  

PubMed Central

It is not known why some species accumulate high concentrations of sucrose in leaves during photosynthesis while others do not. To determine the possible basis, we have studied 10 species, known to differ in the accumulation of sucrose, in terms of activities of sucrose hydrolyzing enzymes. In general, acid invertase activity decreased as leaves expanded; however, activities remaining in mature, fully expanded leaves ranged from low (<10 micromoles per gram fresh weight per hour) to very high (>100 micromoles per gram fresh weight per hour). In contrast, sucrose synthase activities were low and relatively similar among the species (4-10 micromoles per gram fresh weight per hour). Importantly, leaf sucrose concentration, measured at midafternoon, was negatively correlated with acid invertase activity. We propose that sucrose accumulation in vacuoles of species such as soybean and tobacco is prevented by acid invertase-mediated hydrolysis. Initial attempts were made to characterize the relatively high activity of acid invertase from mature soybean leaves. Two apparent forms of the enzyme were resolved by Mono Q chromatography. The two forms had similar affinity for substrate (apparent Km [sucrose] = 3 millimolar) and did not interconvert upon rechromatography. It appeared that the loss of whole leaf invertase activity during expansion was largely the result of changes in one of the enzyme forms. Overall, the results provide a mechanism to explain why some species do not accumulate sucrose in their leaves. Some futile cycling between sucrose and hexose sugars is postulated to occur in these species, and thus, the energy cost of sucrose production may be higher than is generally thought.

Huber, Steven C.

1989-01-01

367

High biobased content epoxy-anhydride thermosets from epoxidized sucrose esters of Fatty acids.  

PubMed

Novel highly functional biobased epoxy compounds, epoxidized sucrose esters of fatty acids (ESEFAs), were cross-linked with a liquid cycloaliphatic anhydride to prepare polyester thermosets. The degree of cure or conversion was studied using differential scanning calorimetry (DSC), and the sol content of the thermosets was determined using solvent extraction. The mechanical properties were studied using tensile testing to determine Young's modulus, tensile stress, and elongation at break. Dynamic mechanical analysis (DMA) was used to determine glass-transition temperature, storage modulus, and cross-link density. The nanomechanical properties of the surfaces were studied using nanoindentation to determine reduced modulus and indentation hardness. The properties of coatings on steel substrates were studied to determine coating hardness, adhesion, solvent resistance, and mechanical durability. Compared with the control, epoxidized soybean oil, the anhydride-cured ESEFAs have high modulus and are hard and ductile, high-performance thermoset materials while maintaining a high biobased content (71-77% in theory). The exceptional performance of the ESEFAs is attributed to the unique structure of these macromolecules: well-defined compact structures with high epoxide functionality. These biobased thermosets have potential uses in applications such as composites, adhesives, and coatings. PMID:21561167

Pan, Xiao; Sengupta, Partha; Webster, Dean C

2011-06-13

368

Analysis of Arabidopsis glutathione-transferases in yeast.  

PubMed

The genome of Arabidopsis thaliana encodes 54 functional glutathione transferases (GSTs), classified in seven clades. Although plant GSTs have been implicated in the detoxification of xenobiotics, such as herbicides, extensive redundancy within this large gene family impedes a functional analysis in planta. In this study, a GST-deficient yeast strain was established as a system for analyzing plant GSTs that allows screening for GST substrates and identifying substrate preferences within the plant GST family. To this end, five yeast genes encoding GSTs and GST-related proteins were simultaneously disrupted. The resulting yeast quintuple mutant showed a strongly reduced conjugation of the GST substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl). Consistently, the quintuple mutant was hypersensitive to CDNB, and this phenotype was complemented by the inducible expression of Arabidopsis GSTs. The conjugating activity of the plant GSTs was assessed by in vitro enzymatic assays and via analysis of exposed yeast cells. The formation of glutathione adducts with dinitrobenzene was unequivocally verified by stable isotope labeling and subsequent accurate ultrahigh-resolution mass spectrometry (ICR-FTMS). Analysis of Arabidopsis GSTs encompassing six clades and 42 members demonstrated functional expression in yeast by using CDNB and NBD-Cl as model substrates. Subsequently, the established yeast system was explored for its potential to screen the Arabidopsis GST family for conjugation of the fungicide anilazine. Thirty Arabidopsis GSTs were identified that conferred increased levels of glutathionylated anilazine. Efficient anilazine conjugation was observed in the presence of the phi, tau, and theta clade GSTs including AtGSTF2, AtGSTF4, AtGSTF6, AtGSTF8, AtGSTF10, and AtGSTT2, none of which had previously been known to contribute to fungicide detoxification. ICR-FTMS analysis of yeast extracts allowed the simultaneous detection and semiquantification of anilazine conjugates as well as catabolites. PMID:22633844

Krajewski, Matthias P; Kanawati, Basem; Fekete, Agnes; Kowalski, Natalie; Schmitt-Kopplin, Philippe; Grill, Erwin

2013-07-01

369

Influence of Internal Sugar Levels on Apoplasmic Retrieval of Exogenous Sucrose in Source Leaf Tissue 1  

PubMed Central

Sugar levels in Beta vulgaris leaves were increased by heat-girdling the petiole and returning the plant to the controlled-environment chamber for 10 and 34 hours. After 10 hours, sucrose influx into the treated leaves was similar to the controls, although sucrose levels increased from 2.1 to 5.3 micromoles per milligram chlorophyll. However, after a 34-hour treatment, sucrose levels increased from 2.1 to 11.5 micromoles per milligram chlorophyll. In this instance, sucrose influx decreased relative to the untreated controls. Decreasing sugar levels by DCMU treatment resulted in a small stimulation of sucrose influx. A similar DCMU treatment applied to leaves of Allium cepa also resulted in an increase in sucrose influx. However, in A. cepa we could not attribute this increase to a lowering of sugar levels, as the kinetic profiles obtained from control leaves did not vary from each other throughout the day, despite considerable changes in sugar levels. Additionally, it appeared that sucrose uptake in onion may be set at some point and remains invariant throughout the day. Similar studies were also conducted on discs cut from mature leaves of Spinacia oleracea var America. Between 1 and 8 hours after the onset of the photoperiod, the sucrose content of the spinach leaves increased from 2.6 to 9.3 micromoles per milligram chlorophyll. A comparison of the kinetic profiles obtained from leaf discs, taken at these times, indicated that sucrose uptake was not influenced by these changes in internal sugar levels. The relationship between the above findings and `trans' inhibition of exogenous sucrose uptake is discussed. Although intermediate changes in sugar levels in sugar beet leaves did not appear to affect sucrose influx, autoradiographic studies revealed that these changes dramatically affected the partitioning of exogenously supplied [14C]sucrose. Our results indicate that while intermediate changes in internal sugar levels have little effect on sucrose influx across the plasmalemma, they may dramatically affect partitioning between the phloem and the mesophyll vacuole. Images Fig. 6 Fig. 7

Wilson, Clyde; Lucas, William J.

1987-01-01

370

High incidence of Aspergillus flavus and aflatoxins in stored groundnut in Ghana and the use of a microbial assay to assess the inhibitory effects of plant extracts on aflatoxin synthesis.  

PubMed

Groundnut samples from 21 selected markets in the 10 regions of Ghana yielded high levels of the aflatoxigenic fungus Aspergillus flavus on half-strength potato dextrose agar. The fungus was associated with 31.7 and 12.8%, respectively, of all damaged and undamaged kernels assayed. Only 0.24% of total kernels assayed yielded A. parasiticus. Other fungi detected from total kernels assayed were A. niger (34%), A. candidus (1.45%), A. tamarii (3.93%), A. ochraceous (5.26%), Fusarium spp. (1.7%) Penicillium spp. (5.19%), a Mucor sp. (2.3%), a Trichoderma sp. (0.2%), Rhizopus stolonifer (12%) and certain unidentifiable fungi (11.72%). Total aflatoxin levels ranging from 5.7 to 22, 168 ppb were identified with damaged kernel samples. The mycotoxin was not detected in 50% of undamaged kernel samples tested and very low levels mostly ranging from 0.1 to 12.2 ppb were associated with the undamaged samples that tested positive for aflatoxins. In a novel in vitro microbial assay to determine the effectiveness of certain plant extracts against aflatoxin synthesis, extracts from Xylopia aethiopica, Monodera myristica, Cinnamomum verum and Piper nigrum permitted fungal growth in 1.5% potato-dextrose broth while completely suppressing NOR formation. These extracts, however, could not suppress NOR formation in a yeast extract sucrose medium. PMID:8981776

Awuah, R T; Kpodo, K A

1996-01-01

371

Thermal, pasting, and gelling properties of wheat and potato starches in the presence of sucrose, glucose, glycerol, and hydroxypropyl ?-cyclodextrin  

Microsoft Academic Search

Thermal, pasting, and gelling properties of wheat and potato starches were studied in the presence of sucrose, glucose, glycerol, and hydroxypropyl ?-cyclodextrin (HP?-CD). Swelling factor of both starches slightly increased up to 20% sucrose and glucose but decreased at 40% concentration (sucrose>glucose). Glycerol did not affect swelling factor of wheat starch even at 40% concentration but decreased it in potato

Anil Gunaratne; Somathilaka Ranaweera; Harold Corke

2007-01-01

372

Swallowing motor pattern triggered and modified by sucrose stimulation in the larvae of the silkworm, Bombyx mori  

Microsoft Academic Search

To determine the contribution of sucrose signals to swallowing motor patterns, a series of behavioral, morphological and electrophysiological experiments were carried out in the larvae of the silkworm, Bombyx mori. The larvae ingested a droplet of sucrose solution applied to the mouth. The rate of ingestion was increased for higher sucrose concentrations. The swallowing movements were produced by a cibarial

Ken Sasaki; Kiyoshi Asaoka

2006-01-01

373

Effect of high sucrose diet on insulin secretion and insulin action: a study in the normal rat  

Microsoft Academic Search

Summary  The effects of chronic high sucrose feeding for 1 month on in vivo and in vitro insulin secretion and on in vivo insulin action were studied in normal male rats. As compared to the standard chow diet, the high sucrose diet induced excess in vivo insulin response to an intravenous glucose load; the high sucrose diet also slightly improved glucose

M. Kergoat; D. Bailbé; B. Portha

1987-01-01

374

Polyglutamine misfolding in yeast  

PubMed Central

Protein misfolding is associated with many human diseases, including neurodegenerative diseases, such as Alzheimer disease, Parkinson disease and Huntington disease. Protein misfolding often results in the formation of intracellular or extracellular inclusions or aggregates. Even though deciphering the role of these aggregates has been the object of intense research activity, their role in protein misfolding diseases is unclear. Here, I discuss the implications of studies on polyglutamine aggregation and toxicity in yeast and other model organisms. These studies provide an excellent experimental and conceptual paradigm that contributes to understanding the differences between toxic and protective trajectories of protein misfolding. Future studies like the ones discussed here have the potential to transform basic concepts of protein misfolding in human diseases and may thus help to identify new therapeutic strategies for their treatment.

2011-01-01

375

Expanding Yeast Knowledge Online  

PubMed Central

The completion of the Saccharomyces cerevisiae genome sequencing project11 and the continued development of improved technology for large-scale genome analysis have led to tremendous growth in the amount of new yeast genetics and molecular biology data. Efficient organization, presentation, and dissemination of this information are essential if researchers are to exploit this knowledge. In addition, the development of tools that provide efficient analysis of this information and link it with pertinent information from other systems is becoming increasingly important at a time when the complete genome sequences of other organisms are becoming available. The aim of this review is to familiarize biologists with the type of data resources currently available on the World Wide Web (WWW).

DOLINSKI, KARA; BALL, CATHERINE A.; CHERVITZ, STEPHEN A.; DWIGHT, SELINA S.; HARRIS, MIDORI A.; ROBERTS, SHANNON; ROE, TAIYUN; CHERRY, J. MICHAEL; BOTSTEIN, DAVID

2011-01-01

376

Skin permeation enhancement by sucrose esters: a pH-dependent phenomenon.  

PubMed

The purpose of the present study was to evaluate the effect of sucrose esters (particularly, sucrose laureate and sucrose oleate in Transcutol) on the percutaneous penetration of a charged molecule as a function of ionization. We have investigated the influence of these sucrose esters on the in vitro diffusion profiles of lidocaine hydrochloride, a weak ionizable base (pKa=7.9), at different pH values, using porcine ear skin as the barrier membrane. As expected, lidocaine flux in the absence of an enhancer, increased from pH 5 to 9 with a corrresponding increase in the level of the unionized base. However, when skin was pretreated with 2% laureate in Transcutol (2% L-TC), drug permeation was higher at pH 5.0 and 7.0 than at 9.0. A different trend was observed in experiments with 2% oleate in Transcutol (2% O-TC), where skin flux was maximal at a more basic pH, when the degree of ionization is low. The results suggest that sucrose laureate enhances the penetration of the ionized form of the drug (12-fold greater flux relative to control), whereas sucrose oleate is more effective in promoting permeation of the unionized species. The structural properties of the sucrose esters as well as the degree of ionization of the drug are important characteristics affecting the transdermal flux of lidocaine. PMID:15878811

Cázares-Delgadillo, J; Naik, A; Kalia, Y N; Quintanar-Guerrero, D; Ganem-Quintanar, A

2005-06-13

377

Maltodextrin can produce similar metabolic and cognitive effects to those of sucrose in the rat.  

PubMed

In the context of the well-documented metabolic and behavioural effects of supplementing rats' diets with access to a sucrose solution, the aim of this study was to compare the impact of 10% sucrose with that of an isoenergetic (10.4%) solution of hydrolysed starch, maltodextrin. This polysaccharide is metabolised at least as rapidly as sucrose and is also very palatable to rats, but does not contain fructose. Each of three experiments contained three groups: one given a sucrose solution, one given a maltodextrin solution and a control group maintained on standard chow and water alone. In Experiment 1 the sucrose and maltodextrin groups were given their supplementary drinks for 2 h each day, while in Experiments 2 and 3 these groups had 24-h access to their supplements. Ad libitum access to maltodextrin produced at least as rapid weight gain as sucrose and in Experiment 2 retroperitoneal fat mass was greater in the two carbohydrate groups than in the control group. Moreover, in Experiment 3, impaired performance on a location recognition task was also found in both carbohydrate groups after only 17 days on the diets. These results indicate that the harmful effects of excess sucrose consumption can also be produced by another rapidly absorbed carbohydrate that does not contain fructose. PMID:24582585

Kendig, Michael D; Lin, Candy S; Beilharz, Jessica E; Rooney, Kieron B; Boakes, Robert A

2014-06-01

378

Molecular Analysis of Sucrose Metabolism of Erwinia amylovora and Influence on Bacterial Virulence  

PubMed Central

Sucrose is an important storage and transport sugar of plants and an energy source for many phytopathogenic bacteria. To analyze regulation and biochemistry of sucrose metabolism of the fire blight pathogen Erwinia amylovora, a chromosomal fragment which enabled Escherichia coli to utilize sucrose as sole carbon source was cloned. By transposon mutagenesis, the scr regulon of E. amylovora was tagged, and its nucleotide sequence was determined. Five open reading frames, with the genes scrK, scrY, scrA, scrB, and scrR, had high homology to genes of the scr regulons from Klebsiella pneumoniae and plasmid pUR400. scrB and scrR of E. amylovora were fused to a histidine tag and to the maltose-binding protein (MalE) of E. coli, respectively. ScrB (53 kDa) catalyzed the hydrolysis of sucrose with a Km of 125 mM. Binding of a MalE-ScrR fusion protein to an scrYAB promoter fragment was shown by gel mobility shifts. This complex dissociated in the presence of fructose but not after addition of sucrose. Expression of the scr regulon was studied with an scrYAB promoter-green fluorescent protein gene fusion and measured by flow cytometry and spectrofluorometry. The operon was affected by catabolite repression and induced by sucrose or fructose. The level of gene induction correlated to the sucrose concentration in plant tissue, as shown by flow cytometry. Sucrose mutants created by site-directed mutagenesis did not produce significant fire blight symptoms on apple seedlings, indicating the importance of sucrose metabolism for colonization of host plants by E. amylovora.

Bogs, Jochen; Geider, Klaus

2000-01-01

379

Differential effects of sucrose and fructose on dietary obesity in four mouse strains  

PubMed Central

We examined sugar-induced obesity in mouse strains polymorphic for Tas1r3, a gene that codes for the T1R3 sugar taste receptor. The T1R3 receptor in the FVB and B6 strains has a higher affinity for sugars than that in the AKR and 129P3 strains. In Experiment 1, mice had 40 days of access to lab chow plus water, sucrose (10 or 34%), or fructose (10 or 34%) solutions. The strains consumed more of the sucrose than isocaloric fructose solutions. The pattern of strain differences in caloric intake from the 10% sugar solutions was FVB > 129P3 = B6 > AKR; and that from the 34% sugar solutions was FVB > 129P3 > B6 ? AKR. Despite consuming more sugar calories, the FVB mice resisted obesity altogether. The AKR and 129P3 mice became obese exclusively on the 34% sucrose diet, while the B6 mice did so on the 34% sucrose and 34% fructose diets. In Experiment 2, we compared total caloric intake from diets containing chow versus chow plus 34% sucrose. All strains consumed 15-29% more calories from the sucrose-supplemented diet. In Experiment 3, we compared the oral acceptability of the sucrose and fructose solutions, using lick tests. All strains licked more avidly for the 10% sucrose solutions. The results indicate that in mice (a) Tas1r3 genotype does not predict sugar-induced hyperphagia or obesity; (b) sucrose solutions stimulate higher daily intakes than isocaloric fructose solutions; and (c) susceptibility to sugar-induced obesity varies with strain, sugar concentration and sugar type.

Glendinnning, John I.; Breinager, Lindsey; Kyrillou, Emily; Lacuna, Kristine; Rocha, Rotsen; Sclafani, Anthony

2010-01-01

380

Biological Sensor for Sucrose Availability: Relative Sensitivities of Various Reporter Genes  

PubMed Central

A set of three sucrose-regulated transcriptional fusions was constructed. Fusions p61RYTIR, p61RYlac, and p61RYice contain the scrR sucrose repressor gene and the promoterless gfp, lacZ, and inaZ reporter genes, respectively, fused to the scrY promoter from Salmonella enterica serovar Typhimurium. Cells of Erwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. While a large variation in sucrose-dependent reporter gene activity was observed in cells harboring all gene fusions, fusions to the inaZ reporter gene yielded a much wider range of activity and were responsive to lower levels of sucrose than either lacZ or gfp. The lacZ reporter gene was found to be more efficient than gfp, requiring approximately 300-fold fewer cells for a detectable response over all concentrations of sucrose. Similarly, inaZ was found to be more efficient than lacZ, requiring 30-fold fewer cells at 1.45 ?M sucrose and 6,100-fold fewer cells at 29 mM sucrose for a quantifiable response. The fluorescence of individual cells containing p61RYTIR was quantified following epifluorescence microscopy in order to relate the fluorescence exhibited by populations of cells in batch cultures with that of individual cells in such cultures. While the mean fluorescence intensity of a population of individual cells increased with increasing concentrations of sucrose, a wide range of fluorescence intensity was seen among individual cells. For most cultures the distribution of fluorescence intensity among individual cells was log-normally distributed, but cells grown in intermediate concentrations of sucrose exhibited two distinct populations of cells, one having relatively low fluorescence and another with much higher fluorescence. When cells were inoculated onto bean leaves, whole-cell ice nucleation and gfp-based biological sensors for sucrose each indicated that the average concentration of sucrose on moist leaf surfaces was about 20 ?M. Importantly, the variation in green fluorescent protein fluorescence of biosensor cells on leaves suggested that large spatial variations in sugar availability occur on leaves.

Miller, William G.; Brandl, Maria T.; Quinones, Beatriz; Lindow, Steven E.

2001-01-01

381

Synthesis of a sucrose dimer with enone tether; a study on its functionalization  

PubMed Central

Summary The reaction of appropriately functionalized sucrose phosphonate with sucrose aldehyde afforded a dimer composed of two sucrose units connected via their C6-positions (‘the glucose ends’). The carbonyl group in this product (enone) was stereoselectively reduced with zinc borohydride and the double bond (after protection of the allylic alcohol formed after reduction) was oxidized with osmium tetroxide to a diol. Absolute configurations of the allylic alcohol as well as the diol were determined by circular dichroism (CD) spectroscopy using the in situ dimolybdenum methodology.

Pakulski, Zbigniew; Gajda, Norbert; Jawiczuk, Magdalena; Frelek, Jadwiga; Cmoch, Piotr

2014-01-01

382

Sucrose permeability as a marker for nonsteroidal anti-inflammatory gastroduodenal injury: how sweet is it?  

PubMed

The authors report that sucrose is a novel permeability marker in the evalution of proximal gastrointestinal (GI) injury. In patients undergoing endoscopy and in volunteers who were chronically taking nonsteroidal anti-inflammatory drugs (NSAIDs), the sucrose permeability test accurately identified patients with severe gastritis and gastric ulcer. The sucrose permeability test did not detect other types of proximal GI injury as reliably. Given the propensity of NSAIDs to cause upper GI injury, the authors suggest that this test can be used to identify people who might be at high risk from the sequelae of NSAID ingestion. This interesting marker deserves further evaluation in targeted prospective studies. PMID:7885621

DeMeo, M

1995-01-01

383

Thermolabile xylanase of the Antarctic yeast Cryptococcus adeliae : production and properties  

Microsoft Academic Search

Xylanase production by the Antarctic psychrophilic yeast Cryptococcus adeliae was increased 4.3 fold by optimizing the culture medium composition using statistical designs. The optimized medium containing\\u000a 24.2 g l?1 xylan and 10.2 g l?1 yeast extract and having an initial pH of 7.5 yielded xylanase activity at 400 nkat (nanokatal) ml?1 after 168-h shake culture at 4?C. In addition, very

Joseph Gomes; Isidore Gomes; Walter Steiner

2000-01-01

384

Saccharomyces cerevisiae Produces a Yeast Substance that Exhibits Estrogenic Activity in Mammalian Systems  

NASA Astrophysics Data System (ADS)

Partially purified lipid extracts of Saccharomyces cerevisiae contain a substance that displaces tritiated estradiol from rat uterine cytosol estrogen receptors. The yeast product induces estrogenic bioresponses in mammalian systems as measured by induction of progesterone receptors in cultured MCF-7 human breast cancer cells and by a uterotrophic response and progesterone receptor induction after administration to ovariectomized mice. The findings raise the possibility that bakers' yeast may be a source of environmental estrogens.

Feldman, David; Stathis, Peter A.; Hirst, Margaret A.; Price Stover, E.; Do, Yung S.; Kurz, Walter

1984-06-01

385

Screening yeast artificial chromosome libraries with robot-aided automation.  

PubMed

Screening of collections of yeast artificial chromosomes utilizing the polymerase chain reaction (PCR) requires large numbers of reactions in parallel. Four steps were implemented to reduce the labor involved: (a) The number of initial samples for DNA extractions was decreased by compressing libraries up to 12-fold. (b) DNA extraction from yeast clones was robot assisted. (c) A BIOMEK 1000 station was adapted to pipette samples for PCR assays. (d) Sample preparation was integrated with a temperature cycler constructed to carry out up to 576 reactions in six 8 x 12-well trays. The implementation of these steps increases the number of reactions per person per day by an order of magnitude. In tests with X-chromosome-specific probes, the robot-aided screening recovered all of the clones detected by slower manual methods. PMID:8043305

Sloan, D D; Blanchard, M M; Burough, F W; Nowotny, V

1993-01-01

386

Vacuoles of Candida yeast as a specialized niche for Helicobacter pylori.  

PubMed

Helicobacter pylori (H. pylori) are resistant to hostile gastric environments and antibiotic therapy, reflecting the possibility that they are protected by an ecological niche, such as inside the vacuoles of human epithelial and immune cells. Candida yeast may also provide such an alternative niche, as fluorescently labeled H. pylori were observed as fast-moving and viable bacterium-like bodies inside the vacuoles of gastric, oral, vaginal and foodborne Candida yeasts. In addition, H. pylori-specific genes and proteins were detected in samples extracted from these yeasts. The H. pylori present within these yeasts produce peroxiredoxin and thiol peroxidase, providing the ability to detoxify oxygen metabolites formed in immune cells. Furthermore, these bacteria produce urease and VacA, two virulence determinants of H. pylori that influence phago-lysosome fusion and bacterial survival in macrophages. Microscopic observations of H. pylori cells in new generations of yeasts along with amplification of H. pylori-specific genes from consecutive generations indicate that new yeasts can inherit the intracellular H. pylori as part of their vacuolar content. Accordingly, it is proposed that yeast vacuoles serve as a sophisticated niche that protects H. pylori against the environmental stresses and provides essential nutrients, including ergosterol, for its growth and multiplication. This intracellular establishment inside the yeast vacuole likely occurred long ago, leading to the adaptation of H. pylori to persist in phagocytic cells. The presence of these bacteria within yeasts, including foodborne yeasts, along with the vertical transmission of yeasts from mother to neonate, provide explanations for the persistence and propagation of H. pylori in the human population. This Topic Highlight reviews and discusses recent evidence regarding the evolutionary adaptation of H. pylori to thrive in host cell vacuoles. PMID:24833856

Siavoshi, Farideh; Saniee, Parastoo

2014-05-14

387

Vacuoles of Candida yeast as a specialized niche for Helicobacter pylori  

PubMed Central

Helicobacter pylori (H. pylori) are resistant to hostile gastric environments and antibiotic therapy, reflecting the possibility that they are protected by an ecological niche, such as inside the vacuoles of human epithelial and immune cells. Candida yeast may also provide such an alternative niche, as fluorescently labeled H. pylori were observed as fast-moving and viable bacterium-like bodies inside the vacuoles of gastric, oral, vaginal and foodborne Candida yeasts. In addition, H. pylori-specific genes and proteins were detected in samples extracted from these yeasts. The H. pylori present within these yeasts produce peroxiredoxin and thiol peroxidase, providing the ability to detoxify oxygen metabolites formed in immune cells. Furthermore, these bacteria produce urease and VacA, two virulence determinants of H. pylori that influence phago-lysosome fusion and bacterial survival in macrophages. Microscopic observations of H. pylori cells in new generations of yeasts along with amplification of H. pylori-specific genes from consecutive generations indicate that new yeasts can inherit the intracellular H. pylori as part of their vacuolar content. Accordingly, it is proposed that yeast vacuoles serve as a sophisticated niche that protects H. pylori against the environmental stresses and provides essential nutrients, including ergosterol, for its growth and multiplication. This intracellular establishment inside the yeast vacuole likely occurred long ago, leading to the adaptation of H. pylori to persist in phagocytic cells. The presence of these bacteria within yeasts, including foodborne yeasts, along with the vertical transmission of yeasts from mother to neonate, provide explanations for the persistence and propagation of H. pylori in the human population. This Topic Highlight reviews and discusses recent evidence regarding the evolutionary adaptation of H. pylori to thrive in host cell vacuoles.

Siavoshi, Farideh; Saniee, Parastoo

2014-01-01

388

Engineering antibodies by yeast display.  

PubMed

Since its first application to antibody engineering 15 years ago, yeast display technology has been developed into a highly potent tool for both affinity maturing lead molecules and isolating novel antibodies and antibody-like species. Robust approaches to the creation of diversity, construction of yeast libraries, and library screening or selection have been elaborated, improving the quality of engineered molecules and certainty of success in an antibody engineering campaign and positioning yeast display as one of the premier antibody engineering technologies currently in use. Here, we summarize the history of antibody engineering by yeast surface display, approaches used in its application, and a number of examples highlighting the utility of this method for antibody engineering. PMID:22450168

Boder, Eric T; Raeeszadeh-Sarmazdeh, Maryam; Price, J Vincent

2012-10-15

389

Predictions with UNIFAC of liquid-solid phase diagrams: application to water-sucrose-glucose, water-sucrose-fructose and water-xylose-mannose  

NASA Astrophysics Data System (ADS)

The objective of this study is to develop a prediction model of solid-liquid equilibria based on the UNIFAC method which is applicable to sugar systems. Three new groups, X, F and G, representing respectively the cyclic structure of D-xylose, D-fructose and D-glucose are introduced and new interaction parameters for these groups are calculated. The use of groups X, F and G permits the identification of mannose as composed of X, OH and CH 2 and of sucrose as composed of G, F and -O-. The model is tested on three ternary systems: water-sucrose-D-glucose; water-sucrose-D-fructose; water-D-xylose-D-mannose. The results compare favourably with the experimental data except in the invariant point region, corresponding to saturation with both solutes. A similar technique could be applied in the prediction of the behaviour of other sugar systems containing these basic rings.

Gabas, N.; Laguérie, C.

1993-03-01

390

Production of Pseudomonas fluorescens P-5 and P-6 for Bean Damping-off Disease  

Microsoft Academic Search

Growth and efficacy of two biological control agents, Pseudomonas fluorescens Flügge, P-5 and P-6, were evaluated in combinations of two carbon (sucrose & molasses) and two nitrogen (urea & yeast extract) sources to optimize control of Rhizoctonia solani Kühn, which is a causal agent of bean damping-off. Both strains were grown in five liquid media including: sucrose + yeast extract,

SAMIRA PEIGHAMI-ASHNAEI; ABBAS SHARIFI-TEHRANI; MASOOD AHMADZADEH; KEIVAN BEHBOUDI

391

ATP can be dispensable for prespliceosome formation in yeast  

Microsoft Academic Search

The first ATP-dependent step in pre-mRNA splicing involves the stable binding of U2 snRNP to form the prespliceosome. We show that a prespliceosome-like complex forms in the absence of ATP in yeast extracts lacking the U2 suppressor protein CUS2. These complexes display the same pre-mRNA and U snRNA requirements as authentic prespliceosomes and can be chased through the splicing pathway,

Rhonda Perriman; Manuel Ares

392

Triacylglycerol lipases of the yeast  

Microsoft Academic Search

All eukaryotes including the yeast contain a lipid storage compartment which is named lipid particle, lipid droplet or oil\\u000a body. Lipids accumulating in this subcellular fraction serve as a depot of energy and building blocks for membrane lipid synthesis.\\u000a In the yeast, the major storage lipids are triacylglycerols (TGs) and steryl esters (SEs). An important step in the life cycle

Karlheinz Grillitsch; Günther Daum

2011-01-01

393

Sociobiology of the budding yeast.  

PubMed

Social theory has provided a useful framework for research with microorganisms. Here I describe the advantages and possible risks of using a well-known model organism, the unicellular yeast Saccharomyces cerevisiae, for sociobiological research. I discuss the problems connected with clear classification of yeast behaviour based on the fitnessbased Hamilton paradigm. Relevant traits include different types of communities, production of flocculins, invertase and toxins, and the presence of apoptosis. PMID:24736156

Wloch-Salamon, Dominika M

2014-04-01

394

Molecular cloning and characterization of scrB, the structural gene for the Streptococcus mutans phosphoenolpyruvate-dependent sucrose phosphotransferase system sucrose-6-phosphate hydrolase.  

PubMed Central

A DNA fragment encoding the sucrose-6-phosphate hydrolase component of the Streptococcus mutans phosphoenolpyruvate-dependent sucrose phosphotransferase system has been recovered from a plasmid-based genomic library of strain GS5. The locus, designated scrB, was found to reside within a 2.9-kilobase-pair restriction fragment present on the chimeric molecule pVA1343 (7.3 kilobase pairs). Minicell analysis of pVA1343-directed translation products revealed that the scrB product synthesized in Escherichia coli V1343 was a single peptide of Mr 57,000. This polypeptide was reactive with antiserum prepared against S. mutans intracellular invertase, which has been previously shown to have an Mr of 43,000 to 48,000. The basis of this difference in Mr was not established but may represent a posttranslational proteolytic event which occurred in S. mutans but not in recombinant V1343. Sucrose-6-phosphate hydrolase purified to homogeneity from V1343 exhibited Michaelis constants of 180 mM for sucrose and 0.08 mM for sucrose-6-phosphate. Deletion analysis of pVA1343 facilitated the assignment of a coding region for the hydrolase within the insert, as well as an orientation for the transcription of scrB. scrB-defective strains of S. mutans constructed by additive integration of an insertionally inactivated scrB locus exhibited the sucrose sensitivity characteristic of this mutant class. Similar loci were detected by DNA-DNA hybridization in additional strains of S. mutans and two strains of Streptococcus cricetus, but not in single strain representatives of S. rattus, S. sobrinus, S. sanguis I and II, S. salivarius, or S. mitis. Images

Lunsford, R D; Macrina, F L

1986-01-01

395

Modeling Huntington disease in yeast  

PubMed Central

Yeast have been extensively used to model aspects of protein folding diseases, yielding novel mechanistic insights and identifying promising candidate therapeutic targets. In particular, the neurodegenerative disorder Huntington disease (HD), which is caused by the abnormal expansion of a polyglutamine tract in the huntingtin (htt) protein, has been widely studied in yeast. This work has led to the identification of several promising therapeutic targets and compounds that have been validated in mammalian cells, Drosophila and rodent models of HD. Here we discuss the development of yeast models of mutant htt toxicity and misfolding, as well as the mechanistic insights gleaned from this simple model. The role of yeast prions in the toxicity/misfolding of mutant htt is also highlighted. Furthermore, we provide an overview of the application of HD yeast models in both genetic and chemical screens, and the fruitful results obtained from these approaches. Finally, we discuss the future of yeast in neurodegenerative research, in the context of HD and other diseases.

Mason, Robert P

2011-01-01

396

The Effect of Sucrose on the Differentiation of Excised Fern Leaf Tissue into Either Gametophytes of Sporophytes 1  

PubMed Central

Excised juvenile leaves of Microgramma vacciniifolia (Polypodiaceae) develop sporophytic regenerants when grown on mineral agar with sucrose. The ratio of sporophytes to gametophytes produced from the leaf tissue increases with higher percentages of sucrose such that at 4% sucrose, the induction of aposporous gametophytes is a rare occurrence. Experiments varying the osmotic potential with sorbitol and those holding the osmotic potential of the culture medium constant while varying the sucrose level indicate that the effect of sucrose on the differentiation of fern leaf tissue into either gametophyte or sporophyte is nutritional rather than osmotic. A significant effect of sucrose in altering the differentiation of fern leaf tissue is the increased rate of senescence promoted by high sucrose concentrations. Images

Hirsch, Ann M.

1975-01-01

397

Long term effects of high fat and sucrose diets on obesity and lymphocyte proliferation in mice  

Microsoft Academic Search

Objective  To clarify the effect of prolonged feeding of a high-fat and sucrose, and to clarify the effect of sucrose instead of other\\u000a carbohydrate on obesity and immunity in C57BL\\/6J mice.\\u000a \\u000a \\u000a \\u000a Methods  We investigated the development of obesity and immune cell function in four groups of mice fed high-fat, high-fat plus high-sucrose,\\u000a high-sucrose, and control diet for 7 months.\\u000a \\u000a \\u000a \\u000a Results  Mice fed high-fat

Natsuko Sato-Mito; M. Suzui; H. Yoshino; T. Kaburagi; K. Sato

2009-01-01

398

Accumulation of trehalose and sucrose in cyanobacteria exposed to matric water stress  

SciTech Connect

The drought-resistant cyanobacteria Phormidium autumnale, strain LPP{sub 4}, and a Chroococcidiopsis sp. accumulated trehalose, sucrose, and both trehalose and sucrose, respectively, in response to matric water stress. Accumulated sugar concentrations reached values of up to 6.2 {mu}g of trehalose per {mu}g of chlorophyll in P. autumnale, 6.9 {mu}g of sucrose per {mu}g of chlorophyll in LPP{sub 4}, and 4.1 {mu}g of sucrose and 3.2 {mu}g of trehalose per {mu}g of chlorophyll in the Chroococcidiopsis sp. The same sugars were accumulated by these cyanobacteria in similar concentrations under osmotic water stress. Cyanobacteria that did not show drought resistance (Plectonema boryanum and Synechococcus strain PCC 7942) did not accumulate significant amounts of sugars when matric water stress was applied.

Hershkovitz, N.; Oren, A.; Cohen, Y. (Hebrew Univ. of Jerusalem (Israel))

1991-03-01

399

Evaluation of the Health Aspects of Sucrose as a Food Ingredient.  

National Technical Information Service (NTIS)

The report by a group of qualified scientists, designated the Select Committee on GRAS Substances (SCOGS), provides an independent evaluation on the safety of sucrose in food at its present or projected levels of use.

1976-01-01

400

Expression of a maize sucrose phosphate synthase in tomato alters leaf carbohydrate partitioning.  

PubMed Central

We isolated a complementary DNA sequence for the enzyme sucrose phosphate synthase (SPS) from maize utilizing a limited amino acid sequence. The 3509-bp cDNA encodes a 1068-amino acid polypeptide. The identity of the cDNA was confirmed by the ability of the cloned sequence to direct sucrose phosphate synthesis in Escherichia coli. Because no plant-specific factors were necessary for enzymatic activity, we can conclude that SPS enzyme activity is conferred by a single gene product. Sequence comparisons showed that SPS is distantly related to the enzyme sucrose synthase. When expressed from a ribulose bisphosphate carboxylase small subunit promoter in transgenic tomatoes, total SPS activity was boosted up to sixfold in leaves and appeared to be physiologically uncoupled from the tomato regulation mechanism. The elevated SPS activity caused a reduction of starch and increase of sucrose in the tomato leaves. This result clearly demonstrates that SPS is involved in the regulation of carbon partitioning in the leaves.

Worrell, A C; Bruneau, J M; Summerfelt, K; Boersig, M; Voelker, T A

1991-01-01

401

Modeling Sucrose Hydrolysis in Dilute Sulfuric Acid Solutions at Pretreatment Conditions for Lignocellulosic Biomass  

SciTech Connect

Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25 g/l sucrose with 0.1-2.0% (w/w) sulfuric acid concentrations were treated at temperatures of 160-200 C for 3-12 min. Sucrose was observed to completely hydrolyze at all treatment conditions. However, appreciable concentrations of fructose and glucose were detected and glucose was found to be significantly more stable than fructose. Different mathematical approaches were used to fit the kinetic parameters for acid-catalyzed thermal degradation of these sugars. Since both sugars may survive dilute acid pretreatment, they could provide an additional carbon source for production of ethanol and other bio-based products.

Bower, S.; Wickramasinghe, R.; Nagle, N. J.; Schell, D. J.

2008-01-01

402

Accumulation of Trehalose and Sucrose in Cyanobacteria Exposed to Matric Water Stress †  

PubMed Central

The drought-resistant cyanobacteria Phormidium autumnale, strain LPP4, and a Chroococcidiopsis sp. accumulated trehalose, sucrose, and both trehalose and sucrose, respectively, in response to matric water stress. Accumulated sugar concentrations reached values of up to 6.2 ?g of trehalose per ?g of chlorophyll in P. autumnale, 6.9 ?g of sucrose per ?g of chlorophyll in LPP4, and 4.1 ?g of sucrose and 3.2 ?g of trehalose per ?g of chlorophyll in the Chroococcidiopsis sp. The same sugars were accumulated by these cyanobacteria in similar concentrations under osmotic water stress. Cyanobacteria that did not show drought resistance (Plectonema boryanum and Synechococcus strain PCC 7942) did not accumulate significant amounts of sugars when matric water stress was applied.

Hershkovitz, Nitzan; Oren, Aharon; Cohen, Yehuda

1991-01-01

403

Regulation of Invertase Levels in Avena Stem Segments by Gibberellic Acid, Sucrose, Glucose, and Fructose 1  

PubMed Central

Gibberellic acid and sucrose play significant roles in the increases in invertase and growth in Avena stem segments. About 80% of invertase is readily solubilized, whereas the rest is in the cell wall fraction. The levels of both types of invertase change in a similar manner in the response to gibberellic acid and sucrose treatment. The work described here was carried out with only the soluble enzyme. In response to a treatment, the level of invertase activity typically follows a pattern of increase followed by decrease; the increase in activity is approximately correlated with the active growth phase, whereas the decrease in activity is initiated when growth of the segments slows. A continuous supply of gibberellic acid retards the decline of enzyme activity. When gibberellic acid was pulsed to the segments treated with or without sucrose, the level of invertase activity increased at least twice as high in the presence of sucrose as in its absence, but the lag period is longer with sucrose present. Cycloheximide treatments effectively abolish the gibberellic acid-promoted growth, and the level of enzyme activity drops rapidly. Decay of invertase activity in response to cycloheximide treatment occurs regardless of gibberellic acid or sucrose treatment or both, and it is generally faster when the inhibitor is administered at the peak of enzyme induction than when given at its rising phase. Pulses with sucrose, glucose, fructose, or glucose + fructose elevate the level of invertase significantly with a lag of about 5 to 10 hours. The increase in invertase activity elicited by a sucrose pulse is about one-third that caused by a gibberellic acid pulse given at a comparable time during mid-phase of enzyme induction, and the lag before the enzyme activity increases is nearly twice as long for sucrose as for gibberellic acid. Moreover, the gibberellic acid pulse results in about three times more growth than the sucrose pulse. Our studies support the view that gibberellic acid, as well as substrate (sucrose) and end products (glucose and fructose), play a significant role in regulating invertase levels in Avena stem tissue, and that such regulation provides a mechanism for increasing the level of soluble saccharides needed for gibberellic acid-promoted growth.

Kaufman, Peter B.; Ghosheh, Najati S.; Lacroix, J. Donald; Soni, Sarvjit L.; Ikuma, Hiroshi

1973-01-01

404

The effects of fruiting positions on cellulose synthesis and sucrose metabolism during cotton (Gossypium hirsutum L.) fiber development.  

PubMed

Cotton (Gossypium hirsutum L.) boll positions on a fruiting branch vary in their contribution to yield and fiber quality. Fiber properties are dependent on deposition of cellulose in the fiber cell wall, but information about the enzymatic differences in sucrose metabolism between these fruiting positions is lacking. Therefore, two cotton cultivars with different sensitivities to low temperature were tested in 2010 and 2011 to quantify the effect of fruit positions (FPs) on fiber quality in relation to sucrose content, enzymatic activities and sucrose metabolism. The indices including sucrose content, sucrose transformation rate, cellulose content, and the activities of the key enzymes, sucrose phosphate synthase (SPS), acid invertase (AI) and sucrose synthase (SuSy) which inhibit cellulose synthesis and eventually affect fiber quality traits in cotton fiber, were determined. Results showed that as compared with those of FP1, cellulose content, sucrose content, and sucrose transformation rate of FP3 were all decreased, and the variations of cellulose content and sucrose transformation rate caused by FPs in Sumian 15 were larger than those in Kemian 1. Under FP effect, activities of SPS and AI in sucrose regulation were decreased, while SuSy activity in sucrose degradation was increased. The changes in activities of SuSy and SPS in response to FP effect displayed different and large change ranges between the two cultivars. These results indicate that restrained cellulose synthesis and sucrose metabolism in distal FPs are mainly attributed to the changes in the activities of these enzymes. The difference in fiber quality, cellulose synthesis and sucrose metabolism in response to FPs in fiber cells for the two cotton cultivars was mainly determined by the activities of both SuSy and SPS. PMID:24586807

Ma, Yina; Wang, Youhua; Liu, Jingran; Lv, Fengjuan; Chen, Ji; Zhou, Zhiguo

2014-01-01

405

The Effects of Fruiting Positions on Cellulose Synthesis and Sucrose Metabolism during Cotton (Gossypium hirsutum L.) Fiber Development  

PubMed Central

Cotton (Gossypium hirsutum L.) boll positions on a fruiting branch vary in their contribution to yield and fiber quality. Fiber properties are dependent on deposition of cellulose in the fiber cell wall, but information about the enzymatic differences in sucrose metabolism between these fruiting positions is lacking. Therefore, two cotton cultivars with different sensitivities to low temperature were tested in 2010 and 2011 to quantify the effect of fruit positions (FPs) on fiber quality in relation to sucrose content, enzymatic activities and sucrose metabolism. The indices including sucrose content, sucrose transformation rate, cellulose content, and the activities of the key enzymes, sucrose phosphate synthase (SPS), acid invertase (AI) and sucrose synthase (SuSy) which inhibit cellulose synthesis and eventually affect fiber quality traits in cotton fiber, were determined. Results showed that as compared with those of FP1, cellulose content, sucrose content, and sucrose transformation rate of FP3 were all decreased, and the variations of cellulose content and sucrose transformation rate caused by FPs in Sumian 15 were larger than those in Kemian 1. Under FP effect, activities of SPS and AI in sucrose regulation were decreased, while SuSy activity in sucrose degradation was increased. The changes in activities of SuSy and SPS in response to FP effect displayed different and large change ranges between the two cultivars. These results indicate that restrained cellulose synthesis and sucrose metabolism in distal FPs are mainly attributed to the changes in the activities of these enzymes. The difference in fiber quality, cellulose synthesis and sucrose metabolism in response to FPs in fiber cells for the two cotton cultivars was mainly determined by the activities of both SuSy and SPS.

Ma, Yina; Wang, Youhua; Liu, Jingran; Lv, Fengjuan; Chen, Ji; Zhou, Zhiguo

2014-01-01

406

Study of the production of fructose and ethanol from sucrose media by Saccharomyces cerevisiae  

Microsoft Academic Search

The production of ethanol and enriched fructose syrups from a synthetic medium with various sucrose concentrations using the mutant Saccharomyces cerevisiae ATCC 36858 was investigated. In batch tests, fructose yields were above 90% of theoretical values for the sucrose concentrations between 35 g\\/l and 257 g\\/l. The specific growth rates and biomass yields were from 0.218 to 0.128 h-1 and

H. Atiyeh; Z. Duvnjak

2001-01-01

407

Serum insulin and glucose in hyperinsulinemic subjects fed three different levels of sucrose13  

Microsoft Academic Search

Twenty-four adult men and women, classified as carbohydrate-sensitive on the basis of an exaggerated insulin response to a sucrose load, consumed diets containing 5. 18. and 33% of calories as sucrose for 6 wk each in a cross-over design. The diets contained identical natural and processed foods except for a patty containing 2, 15, or 30% of the calories as

Sheldon Reiser; Ellen Bohn; Judith Hallfrisch; Otho E. Michaelis; Mark Keeney; Elizabeth S. Prather

408

Effect of temperature on sucrose to ethanol conversion by Zymomonas mobilis strains  

Microsoft Academic Search

Two strains of Zymomonas mobilis were tested for their ability to ferment sucrose to ethanol at elevated temperatures (30–42.5°C). The optimal temperature for efficient sucrose to ethanol conversion was 35°C with 22–27 h fermentation time and 75% conversion efficiency. Increases in magnesium concentration improved one of the strains at 40°C from 38 to 76% ethanol yield efficiency.

E. Lyness; H. W. Doelle

1980-01-01

409

Safety of Iron Sucrose in Hemodialysis Patients Intolerant to Other Parenteral Iron Products  

Microsoft Academic Search

Background\\/Aims: This report summarizes the data gathered in four prospective studies of intravenous iron sucrose therapy administered to iron-deficient hemodialysis patients with a history of intolerance to other parenteral iron preparations. Methods: A total of 130 iron dextran- and\\/or sodium ferric gluconate-sensitive patients received intravenous iron sucrose therapy to correct iron deficiency, and\\/or maintain body iron stores. A history of

Chaim Charytan; Michael H. Schwenk; Mourhege M. Al-Saloum; Bruce S. Spinowitz

2004-01-01

410

Enzymatic synthesis of carbohydrate esters of fatty acid (I) esterification of sucrose, glucose, fructose and sorbitol  

Microsoft Academic Search

The authors attempted to synthesize carbohydrate esters of fatty acids enzymatically in order to overcome the problems associated\\u000a with the chemical processes for the synthesis of commercial sucrose esters. The enzymes used were lipases from microorganisms\\u000a belonging toRhyzopus, Enterbacterium, Aspergillus, Pseudomonas, Chromobacterium, Candida, Mucor andPenicillium. Fatty acids (stearic, oleic and linoleic) and carbohydrates (sucrose, glucose, fructose and sorbitol) used for

Hajime Seino; Tsuyoshi Uchibori; Toshiyuki Nishitani; Sachiko Inamasu

1984-01-01

411

Neuroadaptations in the striatal proteome of the rat following prolonged excessive sucrose intake.  

PubMed

Obesity is a contemporary health problem of rapidly increasing prevalence. One possible cause of obesity is loss of control over consumption of highly palatable foodstuffs, perhaps mirroring the processes involved in drug addiction. Accordingly, the striatum may be a key neural substrate involved in both food and drug craving. We hypothesised here that prolonged exposure to 10 % sucrose solution might cause neuroadaptations in the striatum that are analogous to those previously reported following prolonged exposure to alcohol or recreational drugs. Male Wistar rats were given constant access to 10 % sucrose solution (in addition to normal lab chow and tap water) for 8 months and were compared with control rats receiving no sucrose access. Rats in the sucrose group typically drank more than 100 ml of sucrose solution per day and showed 13 % greater body weight than controls at the end of the 8 months. Striatal dopamine (DA) concentrations were decreased in the sucrose group rats relative to controls. Differential expression of 18 proteins was identified in the striatum of the sucrose group rats relative to controls. Down regulated proteins included pyridoxal phosphate phosphatase, involved in DA synthesis, and glutathione transferase, involved in free radical scavenging. Up regulated proteins included prolactin (which is under negative regulation by DA) and adipose differentiation-related protein, involved in fat synthesis. We hypothesise that DA-related neuroadaptations in the striatum caused by prolonged sucrose intake may partly drive compulsive intake and seeking of high palatability foodstuffs, in a similar way to that observed with drug and alcohol addictions. PMID:24634252

Ahmed, Selina; Kashem, Mohammed Abul; Sarker, Ranjana; Ahmed, Eakhlas U; Hargreaves, Garth A; McGregor, Iain S

2014-05-01

412

Effective solubility parameters of sucrose monoester surfactants obtained by inverse gas chromatography  

Microsoft Academic Search

Two products with a high content of sucrose monoesters were obtained from the commercial products P1670 and S1670, using liquid chromatography. The separation progress was monitored by thin layer chromatography (TLC). Differential scanning calorimetry (DSC) between 293.15K and 473.15K was used to define the transition phase temperature of the sucrose ester mixtures. Specific retention volumes of twelve probe solutes were

C. R. de Schaefer; M. E. F. de Ruiz Holgado; E. L. Arancibia

2008-01-01

413

An in vitro microbial model associated with sucrose to produce dentin caries lesions  

Microsoft Academic Search

The complexity of the oral environment and ethical issues have prompted the development of an in vitro bacterial model to evaluate the effect of frequency of sucrose exposure on dentin caries formation, biofilm composition,\\u000a and pH changes. In the experiment, dentin specimens (n=45) were randomly divided into four groups: control (C), negative control\\u000a (0S), 3S (three sucrose baths), and 6S

Carolina Steiner-Oliveira; Lidiany Karla Azevedo Rodrigues; Iriana Carla Junqueira Zanin; Carolina Lima de Carvalho; Regianne Umeko Kamiya; Anderson Takeo Hara; Marinês Nobre-dos-Santos

2011-01-01

414

Diffusion of sucrose and aspartame in kappa-carrageenan and gellan gum gels  

Microsoft Academic Search

In the process of sweetness release from the food to the human papillae, diffusion of the sweetener through the food is one of the steps. Information on diffusion behaviour of small molecules like sucrose has been studied mainly in connection with blanching or osmotic processes. In this paper, diffusion constants (D) of both sucrose (100 and 150g\\/l) and aspartame (0.8

S Bayarri; I Rivas; E Costell; L Durán

2001-01-01

415

Effect of Sucrose on the Production of Acetaldehyde and Acids by Yogurt Culture Bacteria  

Microsoft Academic Search

Yogurt cultures were grown in homog- enized milk containing 2% fat, 12% solids- not-fat, and 0, 4, 8, 12, and 16%o sucrose. Following incubation, the pH, titratable acidity, acetaldehyde and cell numbers of Lactobacillus bulgaricus and Strepto- coccus thermophilus were determined. In general, growth and acid production were inhibited in media containing 4% or more sucrose. Acetaldehyde produc- tion was

D. D. Bills; C. S. Yang; M. E. Morgan; F. W. Bodyfelt

1972-01-01

416

Sucrose, benzylaminopurine and photoperiod effects on in vitro culture of Kaempferia galanga Linn  

Microsoft Academic Search

Kaempferia galanga is a monocotyledonous plant of the Zingiberaceae family, commonly utilized for medicinal purposes. This study evaluates the effect of different concentrations of sucrose, benzylaminopurine (BA) and photoperiod on in vitro propagation of K. galanga. Murashige and Skoog (MS) medium supplemented with 5 mg L BA and 30 g L sucrose, and a photoperiod with 4 h of light induced the highest shoot

Arvind Bhatt; Ong Boo Kean; Chan Lai Keng

2012-01-01

417

Production of dextransucrase, dextran and fructose from sucrose using Leuconostoc mesenteroides NRRL B512(f)  

Microsoft Academic Search

The production of dextransucrase, dextran and fructose by sucrose fermentation using Leuconostoc mesenteroides NRRL-B512(F) was studied in batch operation in a bioreactor with total working volume of 1.5dm3. The effect of temperature (20 to 40°C), pH (5.5 and 6.7) and sucrose concentration (10 to 120g\\/l) on process performance was studied. The optimum conditions for dextran and fructose production were T=35°C

Mariana Santos; José Teixeira; Al??rio Rodrigues

2000-01-01

418

Metabolic regulation of yeast  

NASA Astrophysics Data System (ADS)

Metabolic regulation which is based on endogeneous and exogeneous process variables which may act constantly or time dependently on the living cell is discussed. The observed phenomena of the regulation are the result of physical, chemical, and biological parameters. These parameters are identified. Ethanol is accumulated as an intermediate product and the synthesis of biomass is reduced. This regulatory effect of glucose is used for the aerobic production of ethanol. Very high production rates are thereby obtained. Understanding of the regulation mechanism of the glucose effect has improved. In addition to catabolite repression, several other mechanisms of enzyme regulation have been described, that are mostly governed by exogeneous factors. Glucose also affects the control of respiration in a third class of yeasts which are unable to make use of ethanol as a substrate for growth. This is due to the lack of any anaplerotic activity. As a consequence, diauxic growth behavior is reduced to a one-stage growth with a drastically reduced cell yield. The pulse chemostat technique, a systematic approach for medium design is developed and medium supplements that are essential for metabolic control are identified.

Fiechter, A.

1982-12-01

419

Reconstitution and Characterization of Budding Yeast ?-Tubulin Complex  

PubMed Central

Nucleation of microtubules is central to assembly of the mitotic spindle, which is required for each cell division. ?-Tubulin is a universal component essential for microtubule nucleation from centrosomes. To elucidate the mechanism of microtubule nucleation in budding yeast we reconstituted and characterized the yeast ?-tubulin complex (Tub4p complex) produced in insect cells. The recombinant complex has the same sedimentation coefficient (11.6 S) as the native complex in yeast cell extracts and contains one molecule of Spc97p, one molecule of Spc98p, and two molecules of Tub4p. The reconstituted Tub4p complex binds preformed microtubules and has a low nucleating activity, allowing us to begin a detailed analysis of conditions that enhance this nucleating activity. We tested whether binding of the recombinant Tub4p complex to the spindle pole body docking protein Spc110p affects its nucleating activity. The solubility of recombinant Spc110p in insect cells is improved by coexpression with yeast calmodulin (Cmd1p). The Spc110p/Cmd1p complex has a small sedimentation coefficient (4.2 S) and a large Stokes radius (14.3 nm), indicative of an elongated structure. The Tub4p complex binds Spc110p/Cmd1p via Spc98p and the Kd for binding is 150 nM. The low nucleation activity of the Tub4p complex is not enhanced when it is bound to Spc110p/Cmd1p, suggesting that it requires additional components or modifications to achieve robust activity. Finally, we report the identification of a large 22 S Tub4p complex in yeast extract that contains multimers of Spc97p similar to ?-tubulin ring complexes found in higher eukaryotic cells.

Vinh, Dani B.N.; Kern, Joshua W.; Hancock, William O.; Howard, Jonathon; Davis, Trisha N.

2002-01-01

420

382 An Unusual Reaction to Intravenous Iron Sucrose  

PubMed Central

Background Intravenous (IV) iron dextran, the original parenteral iron formulation, is associated with a high incidence of non-IgE mediated hypersensitivity. Newer formulations of IV iron therapies include low molecular weight iron sucrose (IS) and sodium ferric gluconate complex (SFGC) without dextran, reducing severe adverse reactions by 93%. A case of a rare reaction to IV IS associated with generalized skin pruritus and difficulty in breathing is reported. Methods A 62-year-old Caucasian male with multiple gastric surgeries, secondary to recurrent gastric ulcers and gastric outlet obstruction, presented with severe iron deficiency anemia (IDA) requiring IV iron therapy. Results Chronic malnutrition and malabsorption, associated with difficulty in tolerating oral and jejunostomy tube (J-tube) feedings, resulted in a two month 30 pound weight loss. Oral iron supplementation via a J-tube did not improve the IDA. Prior administrations of IV iron dextran resulted in flushing, generalized urticaria and angioedema associated with pruritus of the face and extremities within ten minutes of infusion. The allergy/immunology service was consulted. Premedication with IV diphenhydramine, 50 mg, prednisone via J-tube, 32 mg, and IV ranitidine, 50 mg, was followed with slow administration of a test dose of IS, 25 mg, at 1.6 mg/min. Within 30 minutes of the IV IS infusion, symptoms of nausea, flushing, and generalized pruritus, and difficulty in breathing were noted. The infusion was stopped and treatment with IV methyprednisolone, 125 mg, resulted in resolution of the reaction over several hours. No eosinophilia or elevated liver transaminases occurred. Subsequently, the infusion was reattempted: pre-medications consisted of IV methylprednisolone, 60 mg, IV diphenhydramine, 50 mg, and IV ranitidine, 50 mg, 75 minutes prior to the infusion of IS, 275 mg, 1.5 mg/min. Treatment was tolerated without adverse effects. Conclusions A rare systemic reaction to IV IS is reported. Pretreatment with methylprednisolone, diphenhydramine and ranitidine 75 minutes before IS infusion was successful.

Balduzzi, Michael; Rashid, Daanish; Butt, Ahmed; Lockey, Richard F.; Ledford, Dennis

2012-01-01

421

A Sucrose-derived Scaffold for Multimerization of Bioactive Peptides  

PubMed Central

A spherical molecular scaffold bearing eight terminal alkyne groups was synthesized in one step from sucrose. One or more copies of a tetrapeptide azide, either N3(CH2)5(C=O)-His-dPhe-Arg-Trp-NH2 (MSH4) or N3(CH2)5(C=O)-Trp-Met-Asp-Phe-NH2 (CCK4), were attached to the scaffold via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Competitive binding assays using Eu-labeled probes based on the superpotent ligands Ser-Tyr-Ser-Nle-Glu-His-dPhe-Arg-Trp-Gly-Lys-Pro-Val-NH2 (NDP-?-MSH) and Asp-Tyr-Met-Gly-Trp-Met-Asp-Phe-NH2 (CCK8) were used to study the interactions of monovalent and multivalent MSH4 and CCK4 constructs with Hek293 cells engineered to overexpress MC4R and CCK2R. All of the monovalent and multivalent MSH4 constructs exhibited binding comparable to that of the parental ligand, suggesting that either the ligand spacing was inappropriate for multivalent binding, or MSH4 is too weak a binder for a second “anchoring” binding event to occur before the monovalently-bound construct is released from the cell surface. In contrast with this behavior, monovalent CCK4 constructs were significantly less potent than the parental ligand, while multivalent CCK4 constructs were as or more potent than the parental ligand. These results are suggestive of multivalent binding, which may be due to increased residence times for monovalently bound CCK4 constructs on the cell surface relative to MSH4 constructs, the greater residence time being necessary for the establishment of multivalent binding.

Rao, Venkataramanarao; Alleti, Ramesh; Xu, Liping; Tafreshi, Narges K.; Morse, David L.; Gillies, Robert J.; Mash, Eugene A.

2011-01-01

422

Snowdrift game dynamics and facultative cheating in yeast.  

PubMed

The origin of cooperation is a central challenge to our understanding of evolution. The fact that microbial interactions can be manipulated in ways that animal interactions cannot has led to a growing interest in microbial models of cooperation and competition. For the budding yeast Saccharomyces cerevisiae to grow on sucrose, the disaccharide must first be hydrolysed by the enzyme invertase. This hydrolysis reaction is performed outside the cytoplasm in the periplasmic space between the plasma membrane and the cell wall. Here we demonstrate that the vast majority ( approximately 99 per cent) of the monosaccharides created by sucrose hydrolysis diffuse away before they can be imported into the cell, serving to make invertase production and secretion a cooperative behaviour. A mutant cheater strain that does not produce invertase is able to take advantage of and invade a population of wild-type cooperator cells. However, over a wide range of conditions, the wild-type cooperator can also invade a population of cheater cells. Therefore, we observe steady-state coexistence between the two strains in well-mixed culture resulting from the fact that rare strategies outperform common strategies-the defining features of what game theorists call the snowdrift game. A model of the cooperative interaction incorporating nonlinear benefits explains the origin of this coexistence. We are able to alter the outcome of the competition by varying either the cost of cooperation or the glucose concentration in the media. Finally, we note that glucose repression of invertase expression in wild-type cells produces a strategy that is optimal for the snowdrift game-wild-type cells cooperate only when competing against cheater cells. PMID:19349960

Gore, Jeff; Youk, Hyun; van Oudenaarden, Alexander

2009-05-14

423

Extraction of regulatory gene\\/protein networks from Medline  

Microsoft Academic Search

Motivation: We have previously developed a rule-based approach for extracting information on the regulation of gene expression in yeast. The biomedical literature, however, contains information on several other equally important regulatory mechanisms, in particular phos- phorylation, which we now expanded for our rule-based system also to extract. Results: This paper presents new results for extraction of relational information from biomedical

Jasmin Saric; Lars Juhl Jensen; Rossitza Ouzounova; Isabel Rojas; Peer Bork

2006-01-01

424

Is there a specific role for sucrose in sports and exercise performance?  

PubMed

The consumption of carbohydrate before, during, and after exercise is a central feature of the athlete's diet, particularly those competing in endurance sports. Sucrose is a carbohydrate present within the diets of athletes. Whether sucrose, by virtue of its component monosaccharides glucose and fructose, exerts a meaningful advantage for athletes over other carbohydrate types or blends is unclear. This narrative reviews the literature on the influence of sucrose, relative to other carbohydrate types, on exercise performance or the metabolic factors that may underpin exercise performance. Inference from the research to date suggests that sucrose appears to be as effective as other highly metabolizable carbohydrates (e.g., glucose, glucose polymers) in providing an exogenous fuel source during endurance exercise, stimulating the synthesis of liver and muscle glycogen during exercise recovery and improving endurance exercise performance. Nonetheless, gaps exist in our understanding of the metabolic and performance consequences of sucrose ingestion before, during, and after exercise relative to other carbohydrate types or blends, particularly when more aggressive carbohydrate intake strategies are adopted. While further research is recommended and discussed in this review, based on the currently available scientific literature it would seem that sucrose should continue to be regarded as one of a variety of options available to help athletes achieve their specific carbohydrate-intake goals. PMID:23630082

Wallis, Gareth A; Wittekind, Anna

2013-12-01

425

Stability of lyophilized sucrose formulations of an IgG1: subvisible particle formation.  

PubMed

Eight lyophilized formulations of a IgG1 monoclonal antibody (MAb) were prepared containing increasing levels of sucrose. In addition, three of the formulations had sorbitol added at a level of 5% w/w relative to sucrose. The samples were stored for up to 4 weeks at 40°C, which is well below the Tg. Upon reconstitution, the levels of subvisible particles were measured using microflow imaging (MFI). The formulation containing no sucrose contained exceedingly high levels of subvisible particles, accounting for as much as 25% of the weight of the protein. Addition of sucrose markedly decreased the number of subvisible particles, with the maximal sucrose:protein weight ratio being 2:1 (the highest level tested). Addition of sorbitol further decreased subvisible particle levels, even for formulations where the sucrose:protein ratio was relatively high. This suggests that even small amounts of a plasticizer like sorbitol can improve the storage stability of a lyophilized antibody formulation, probably by dampening ?-relaxations within the amorphous glass. PMID:22813478

Davis, Janice M; Zhang, Ning; Payne, Robert W; Murphy, Brian M; Abdul-Fattah, Ahmad M; Matsuura, James E; Herman, Alan C; Manning, Mark Cornell

2013-01-01

426

Moderate high fat diet increases sucrose self-administration in young rats.  

PubMed

We have previously reported that a moderately high fat diet increases motivation for sucrose in adult rats. In this study, we tested the motivational, neurochemical, and metabolic effects of the high fat diet in male rats transitioning through puberty, during 5-8 weeks of age. We observed that the high fat diet increased motivated responding for sucrose, which was independent of either metabolic changes or changes in catecholamine neurotransmitter metabolites in the nucleus accumbens. However, AGRP mRNA levels in the hypothalamus were significantly elevated. We demonstrated that increased activation of AGRP neurons is associated with motivated behavior, and that exogenous (third cerebroventricular) AGRP administration resulted in significantly increased motivation for sucrose. These observations suggest that increased expression and activity of AGRP in the medial hypothalamus may underlie the increased responding for sucrose caused by the high fat diet intervention. Finally, we compared motivation for sucrose in pubertal vs. adult rats and observed increased motivation for sucrose in the pubertal rats, which is consistent with previous reports that young animals and humans have an increased preference for sweet taste, compared with adults. Together, our studies suggest that background diet plays a strong modulatory role in motivation for sweet taste in adolescent animals. PMID:23023044

Figlewicz, Dianne P; Jay, Jennifer L; Acheson, Molly A; Magrisso, Irwin J; West, Constance H; Zavosh, Aryana; Benoit, Stephen C; Davis, Jon F

2013-02-01

427

Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure  

SciTech Connect

Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the {beta}-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the {beta}-adrenergic pathway, adenylate cyclase activity and {beta}-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. {beta}-Adrenergic receptors were identified in BAT using ({sup 125}I)iodocyanopindolol. Binding sites had the characteristics of mixed {beta}{sub 1}- and {beta}{sub 2}-type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in {beta}-adrenergic receptor density due to a loss of the {beta}{sub 1}-adrenergic subtype. This BAT {beta}-adrenergic receptor downregulation was tissue specific, since myocardial {beta}-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of {beta}-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability.

Scarpace, P.J.; Baresi, L.A.; Morley, J.E. (Veterans Administration Medical Center, Los Angeles, CA (USA) Univ. of California, Los Angeles (USA))

1987-12-01

428

Moderate High Fat Diet Increases Sucrose Self-Administration In Young Rats  

PubMed Central

We have previously reported that a moderately high fat diet increases motivation for sucrose in adult rats. In this study, we tested the motivational, neurochemical, and metabolic effects of the high fat diet in male rats transitioning through puberty, during 5-8 weeks of age. We observed that the high fat diet increased motivated responding for sucrose, which was independent of either metabolic changes or changes in catecholamine neurotransmitter metabolites in the nucleus accumbens. However, AGRP mRNA levels in the hypothalamus were significantly elevated. We demonstrated that increased activation of AGRP neurons is associated with motivated behavior, and that exogenous (third cerebroventricular) AGRP administration resulted in significantly increased motivation for sucrose. These observations suggest that increased expression and activity of AGRP in the medial hypothalamus may underlie the increased responding for sucrose caused by the high fat diet intervention. Finally, we compared motivation for sucrose in pubertal vs. adult rats and observed increased motivation for sucrose in the pubertal rats, which is consistent with previous reports that young animals and humans have an increased preference for sweet taste, compared with adults. Together, our studies suggest that background diet plays a strong modulatory role in motivation for sweet taste in adolescent animals.

Figlewicz, Dianne P.; Jay, Jennifer L.; Acheson, Molly A.; Magrisso, Irwin J.; West, Constance H.; Zavosh, Aryana; Benoit, Stephen C.; Davis, Jon F.

2012-01-01

429

Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9.  

PubMed

Angiosperms developed floral nectaries that reward pollinating insects. Although nectar function and composition have been characterized, the mechanism of nectar secretion has remained unclear. Here we identify SWEET9 as a nectary-specific sugar transporter in three eudicot species: Arabidopsis thaliana, Brassica rapa (extrastaminal nectaries) and Nicotiana attenuata (gynoecial nectaries). We show that SWEET9 is essential for nectar production and can function as an efflux transporter. We al