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PubMed2005

Overexpression of Mycobacterium tuberculosis manB, a phosphomannomutase that increases phosphatidylinositol mannoside biosynthesis in Mycobacterium smegmatis and mycobacterial association with human macrophages.

Mycobacterium tuberculosis (M. tb) pathogenesis involves the interaction between the mycobacterial cell envelope and host macrophage, a process mediated, in part, by binding of the mannose caps of M. tb lipoarabinomannan (ManLAM) to the macrophage mannose receptor (MR). A presumed critical step in the biosynthesis of ManLAM, and other mannose-containing glycoconjugates, is the conversion of mannose-6-phosphate to mannose-1-phosphate, by a phosphomannomutase (PMM), to produce GDP-mannose, the primary mannose-donor in mycobacteria. We have identified four M. tb H37Rv genes with similarity to known PMMs. Using in vivo complementation of PMM and phosphoglucomutase (PGM) deficient strains of Pseudomonas aeruginosa, and an in vitro enzyme assay, we have identified both PMM and PGM activity from one of these genes, Rv3257c (MtmanB). MtmanB overexpression in M. smegmatis produced increased levels of LAM, lipomannan, and phosphatidylinositol mannosides (PIMs) compared with control strains and led to a 13.3 +/- 3.9-fold greater association of mycobacteria with human macrophages, in a mannan-inhibitable fashion. This increased association was mediated by the overproduction of higher order PIMs that possess mannose cap structures. We conclude that MtmanB encodes a functional PMM involved in the biosynthesis of mannosylated lipoglycans that participate in the association of mycobacteria with macrophage phagocytic receptors.

Bacterial Proteins↗

PubMed2004

MAPMAN: a user-driven tool to display genomics data sets onto diagrams of metabolic pathways and other biological processes.

MAPMAN is a user-driven tool that displays large data sets onto diagrams of metabolic pathways or other processes. SCAVENGER modules assign the measured parameters to hierarchical categories (formed 'BINs', 'subBINs'). A first build of TRANSCRIPTSCAVENGER groups genes on the Arabidopsis Affymetrix 22K array into >200 hierarchical categories, providing a breakdown of central metabolism (for several pathways, down to the single enzyme level), and an overview of secondary metabolism and cellular processes. METABOLITESCAVENGER groups hundreds of metabolites into pathways or groups of structurally related compounds. An IMAGEANNOTATOR module uses these groupings to organise and display experimental data sets onto diagrams of the users' choice. A modular structure allows users to edit existing categories, add new categories and develop SCAVENGER modules for other sorts of data. MAPMAN is used to analyse two sets of 22K Affymetrix arrays that investigate the response of Arabidopsis rosettes to low sugar: one investigates the response to a 6-h extension of the night, and the other compares wild-type Columbia-0 (Col-0) and the starchless pgm mutant (plastid phosphoglucomutase) at the end of the night. There were qualitatively similar responses in both treatments. Many genes involved in photosynthesis, nutrient acquisition, amino acid, nucleotide, lipid and cell wall synthesis, cell wall modification, and RNA and protein synthesis were repressed. Many genes assigned to amino acid, nucleotide, lipid and cell wall breakdown were induced. Changed expression of genes for trehalose metabolism point to a role for trehalose-6-phosphate (Tre6P) as a starvation signal. Widespread changes in the expression of genes encoding receptor kinases, transcription factors, components of signalling pathways, proteins involved in post-translational modification and turnover, and proteins involved in the synthesis and sensing of cytokinins, abscisic acid (ABA) and ethylene revealing large-scale rewiring of the regulatory network is an early response to sugar depletion.

Abscisic Acid↗

PubMed1979

Anomalous mixed lymphocyte culture reactivity between HLA--A, --B, --C, --DR identical siblings.

Complete HLA typing including HLA--A, --B, --C, --DR (D related B cell typing), --D, mixed lymphocyte culture (MLC), and primed lymphocyte testing (PLT), together with complete red blood cell (RBC), glyoxalase (GLO), GBG (Factor B), and phosphoglucomutase 3 (PGM3) typings were performed on a informative family. The five siblings inherited the four possible combinations of parental HLA haplotypes, and two of the siblings were HLA--A, --B, --C and --DR identical. Repeated MLC testing of the family revealed positive mixed lymphocyte reactivity in all combinations. B cell typing for the DR specificities demonstrated no variation from the expected inheritance pattern and specifically no recombination event. GBG and GLO typings militated against a recombination involving the paternal chromosome. HLA--D testing revealed that only one of the HLA--A, --B, --C, and --DR identical siblings gave typing responses to the HLA--Dw3 specificity present on that maternal haplotype. Utilizing HLA haploidentical combinations, lymphocytes were primed against the four parental haplotypes and the non-Dw3 haplotype of interest (Aw24--B8--DRw3--LDY) in the PLT. The sibling inheriting this haplo-type did not restimulate cells primed against the A2--B40--DRW6--LDY specificity. Furthermore, no discrimination was observed in the restimulation of lymphocytes primed against this haplo-type. Possible interpretations of these family data include: a spontaneous mutation, non-major histocompatibility locus (MHC) stimulation, and HLA--DR/D recombination.

B-Lymphocytes↗

PubMed1982

The biosynthesis and linkage of teichuronic acid to peptidoglycan in Bacillus licheniformis.

Membrane and wall-membrane preparations of Bacillus licheniformis 94 will, if supplied with the appropriate precursors, synthesize teichuronic acid and link it to peptidoglycan although teichuronic acid is absent from walls of this organism. B. licheniformis 94 lacks phosphoglucomutase activity and therefore cannot synthesize the precursor UDPglucuronic acid. The initial reaction of teichuronic acid biosynthesis is catalysed by a translocase and results in the formation of polyprenyl-diphospho-N-acetylgalactosamine and the release of UMP. This reaction is not inhibited by tunicamycin. The disaccharide repeating unit of the polymer is then formed by the transfer of glucuronic acid from UDPglucuronic acid with the release of UDP. Polymerization of the repeating units occurs by incorporation of new units at the reducing terminus of the growing teichuronic acid chain and the release of polyprenyl diphosphate. The subsequent dephosphorylation of the lipid diphosphate for reuse in the biosynthesis cycle is inhibited by bacitracin. Linkage to peptidoglycan occurs by the formation of a phosphodiester bond between the reducing N-acetylgalactosamine terminus of the teichuronic acid chain and a 6-hydroxyl group of a muramic acid residue in the glycan of peptidoglycan. Wall-membrane preparations synthesizing teichuronic acid, poly(glycerol phosphate) teichoic acid and peptidoglycan link the teichuronic and teichoic acids to different glycan chains.

Anti-Bacterial Agents↗

PubMed1989

The antiglycogenolytic action of 1-deoxynojirimycin results from a specific inhibition of the alpha-1,6-glucosidase activity of the debranching enzyme.

The glucose analogue 1-deoxynojirimycin (dNOJ) and some of its N-substituted derivatives have recently been described as potent inhibitors of the hepatic glycogenolysis induced by glucagon, Ca2+ ionophores or anoxia. The inhibition increased with time, in spite of a persistently high level of phosphorylase a [Bollen, M., Vandebroeck, A. & Stalmans, W. (1988) Biochem. Pharmacol. 37, 905-909]. dNOJ equilibrates within 1 min across the plasma membrane of hepatocytes. It is not phosphorylated or oxidized in the cell. The observation that dNOJ did not affect gluconeogenesis excludes the possibility that glucose-6-phosphatase is the target for the inhibition of glucose production from glycogen. Neither were the catalytic activities of phosphoglucomutase and phosphorylase a affected by the compound. dNOJ and two N-substituted derivatives inhibited instantaneously and completely the alpha-1,6-glucosidase activity of the debranching enzyme, with I50 values in the mumolar range. In contrast, the glucanotransferase activity of the latter enzyme was not inhibited by the compounds at 0.2 mM. The effect of dNOJ was further studied in an in vitro model system of glycogenolysis. The results were compatible with a block of glycogenolysis at the time when phosphorylase has removed the available glucosyl residues from the outer chains of the glycogen particles. This mechanism appears to account for the lag in the response of glycogenolysis to dNOJ.

1,4-alpha-Glucan Branching Enzyme↗

PubMed2006

A macroarray expression analysis of novel cDNAs vital for growth initiation and primary metabolism during development of Heterobasidion parviporum conidiospores.

The pathogen Heterobasidion parviporum causes significant losses to forest industries in Europe and North America. The fungus is spread by basidiospores on fresh stumps where it differentiates into a specialized infection hyphae to colonize its host. This differentiation is driven by recognition and its strategic success lies in its ability to do this rapidly and efficiently. To investigate gene expression pattern during the spore germination stages, mRNA of germinated and ungerminated conidiospores of H. parviporum harvested at distinct developmental time points (18, 36, 72 and 120 h) corresponding to periods of isotropic/germ tube emergence, polarized apical, early and late mycelial lateral branching growth stages was hybridized to macroarrays containing 338 cDNAs from H. parviporum. The results of the statistical analysis identified a total of 24, 39, 38 and 30 genes that were differentially upregulated at 18, 36, 72 and 120 h, respectively, relative to time 0. The number of the downregulated genes was 4, 6, 8 and 13 genes respectively. During isotropic, polarized and mycelial growth stages, majority of the differentially expressed genes belonged to functional categories metabolism (21-32%) and protein formation (21-30%). Real-time polymerase chain reaction (real-time-PCR) data essentially confirmed the macroarray analyses. The real-time-PCR result showed that transcript levels of genes involved in glucose metabolism (phosphoglucomutase), amino acid metabolism (arginase, delta-1-pyrroline-5-carboxylate reductase, sulfur metabolism-negative regulator, imidazoleglycerol phosphate dehydratase) and protein synthesis (40S ribosomal protein S15) were significantly increased during polarized growth (36 h) stage but decreased at early and late stages of mycelial growth (72-120 h). An understanding of the various molecular and physiological processes during the development of H. parviporum spores is an important step towards the goal of identifying novel antifungal strategies.

Gene Expression Profiling↗

PubMed2006

Rapid identification of clinical Trichoderma longibrachiatum isolates by cellulose-acetate electrophoresis-mediated isoenzyme analysis.

Cellulose-acetate electrophoresis was used to investigate isoenzyme polymorphism among ten clinical and 11 non-clinical isolates of Trichoderma. Initial testing of 13 enzyme systems for activity and resolution of bands showed that seven were appropriate for identifying the different species. Each of the enzyme systems investigated (glucose-6-phosphate dehydrogenase, glucose-6-phosphate isomerase, 6-phosphogluconate dehydrogenase, peptidases A, B and D, and phosphoglucomutase) was diagnostic for at least one species. On the basis of the results of isoenzyme analysis, several isolates identified originally as Trichoderma pseudokoningii, T. koningii or T. citrinoviride were re-identified as T. longibrachiatum, in agreement with sequence analysis data for the internal transcribed spacer region of the isolates. The availability of a quick, inexpensive and reliable diagnostic tool for the identification of T. longibrachiatum isolates is important, as most clinical Trichoderma isolates belong to T. longibrachiatum. Furthermore, as many different enzyme systems are available, the method may also be suitable for the identification of other clinically relevant fungal species.

Electrophoresis, Cellulose Acetate↗

PubMedDate not supplied

Activities of enzymes of carbohydrate and energy metabolism of the spores of the microsporidian, Nosema grylli.

The presence of 14 enzymes was investigated using purified spores of the microsporidian Nosema grylli from fat body of the crickets Gryllus bimaculatus. Glucose 6-phosphate dehydrogenase (EC 1.1.1.49), phosphoglucomutase (EC 5.4.2.2), phosphoglucose isomerase (EC 5.3.1.9), fructose 6-phosphate kinase (EC 2.7.1.11), aldolase (EC 4.1.2.13), 3-phosophoglycerate kinase (EC 2.7.2.3), pyruvate kinase (EC 2.7.1.40) and glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) were detected with activities of 15 +/- 1, 7 +/- 1, 1,549 +/- 255, 10 +/- 1, 5 +/- 1, 16 +/- 4, 6 +/- 1 and 16 +/- 2 nmol/min mg protein, respectively. Hexokinase (EC 2.7.1.1), NAD-dependent malate dehydrogenase (EC 1.1.1.37), malic enzyme (EC 1.1.1.40), lactate dehydrogenase (EC 1.1.1.27), alcohol dehydrogenase (EC 1.1.1.1) and succinate dehydrogenase (EC 1.3.99.1) were not detectable. These results suggest the catabolism of carbohydrates in microsporidia occurs via the Embden-Meyerhof pathway. Glycerol 3-phosphate dehydrogenase may reoxidize NADH which is produced by glyceraldehyde 3-phosphate dehydrogenase in glycolysis.

Animals↗

PubMedDate not supplied

Entamoeba dispar: cultivation with sterilized Crithidia fasciculata.

Four isolates of Entamoeba dispar identified by their hexokinase and phosphoglucomutase isoenzyme profile and by their failure to react with Entamoeba histolytica-specific monoclonal antibody (4G6) could be grown in either Diamond's BI-S-33 medium, newly developed BCSI-S (Biosate cysteine starch iron-serum) medium, or casein-free YI-S medium in the presence of Crithidia fasciculata (ReF-1:PRR) sterilized by heating 56 degrees C for 30 min and subsequent incubation with 1% hydrogen peroxide for 24 hours at 4 degrees C. After the cultures were maintained for over 50 passages, the amebae were identified as E. dispar by isoenzyme analysis, polymerase chain reaction with E. histolytica- and E. dispar-specific primers, i.e. p11 plus p12 and p13 plus p14, respectively, and by negative reactivity with monoclonal antibody 4G6. The flagellates added to the culture were judged to be metabolically inactive based on the results of nuclear magnetic resonance spectroscopy, electron microscopy, and polarographic analysis. All of these findings suggest that E. dispar can grow in vitro with metabolically inactive C. fasciculata as a culture associate.

Animals↗

PubMed1991

Variations in cytotoxicity and isoenzyme patterns of uncloned and cloned cultures of axenic Entamoeba histolytica.

Five clones of axenic Entamoeba histolytica (HMI) grown as discrete colonies in semisolid agar medium were adapted in liquid medium and labelled as HMI-C121, HMI-C131, HMI-C143, HMI-C144 and HMI-C145. The clone HMI-C121 was more cytotoxic to the cultured Baby Hamster Kidney (BHK) cells while all other clones were significantly (P less than 0.001) less cytotoxic as compared to the cloned HMI-C121 and uncloned E. histolytica (HMI). The uncloned Indian axenic E. histolytica (KCG:0986:11) as well as E. histolytica (NIH:200) cultures were significantly (P less than 0.001) less cytotoxic to cultured BHK cells. No difference in the electromobility of maleate NADP oxidoreductase (ME) or glucophosphate isomerase (GPI) isoenzyme in the lysates of all the cloned and uncloned cultures of E. histolytica was observed. The clones HMI-C121, HMI-C131, HMI-G143 and HMI-C144 had three bands of hexokinase (HK) while all uncloned cultures and one of clones, HMI-C145 had only two bands. Though cloned and uncloned cultures had a single PGM band, the relative electromobility (rf) of phosphoglucomutase (PGM) for clone HMI-C131, HMI-C143 HMI-C144 was relatively less (rf 0.075) and these were also significantly (P less than 0.001) less cytotoxic to BHK cells as compared to clone HMI-C121. It is felt that axenic E. histolytica culture consists of several populations (clones) and expression of isoenzymes pattern or cytotoxic potentials would depend upon the population which predominantly multiples and outgrows other populations in the culture system.

Animals↗

PubMed1994

Multilocus enzyme typing of human and animal strains of Clostridium perfringens.

Multilocus enzyme electrophoresis was developed to evaluate the genetic diversity of 71 human strains and 17 animal strains of Clostridium perfringens. Crude protein extracts, obtained by sonication of washed bacteria, were analyzed by polyacrylamide-agarose gel electrophoresis to characterize electrophoretic mobility variants of seven enzymes (esterase, glutamate dehydrogenase, glutamic-oxaloacetic transaminase, nucleoside phosphorylase, phosphoglucose isomerase, phosphoglucomutase, threonine dehydrogenase). Genetic diversity of the enzyme loci ranged from 0.340 to 0.813. Sixty-nine electrophoretic types were described among the 88 strains tested and the index of discrimination was 0.994. All strains were typable, and epidemiological relationships between isolates could be established. This method showed a fair correlation with esterase electrophoretic typing based on hydrolytic and electrophoretic polymorphism of esterases. This work demonstrates that multilocus enzyme polymorphism is a reliable and discriminant marker of genetic diversity of strains of C. perfringens.

Animals↗

PubMed2004

Molecular effects of lithium.

Bipolar affective disorder is a common, severe, chronic, and often life-threatening illness, associated with other medical and psychiatric conditions (i.e., co-morbidity). The treatment of this devastating disorder was revolutionized by the discovery of lithium's antimanic effects over fifty years ago. Recent molecular and cellular biological studies have identified a number of unexpected targets for this monovalent cation, notably glycogen synthase kinase-3 and neurotrophic signaling cascades. These findings are leading to a reconceptualization of the biological underpinnings of bipolar disorder and are resulting in considerable interest in utilizing lithium for the treatment of certain neurodegenerative disorders. We review recent insights into lithium's actions including its direct inhibitory actions on inositol monophosphatase, inositol polyphosphate 1-phosphatase, glycogen synthase kinase-3, fructose 1,6-bisphosphatase, bisphosphate nucleotidase, and phosphoglucomutase enzymes. We also discuss lithium's intracellular downstream targets including adenylate cyclase, the phosphoinositol cascade (and its effect on protein kinase C), arachidonic acid metabolism, and effects on neurotrophic cascades. Many of the new insights of lithium's actions may lead to the strategic development of improved therapeutics for the treatment of bipolar disorder.

Bipolar Disorder↗

PubMed1972

Somatic cell genetic assignment of peptidase C and the Rh linkage group to chromosome A-1 in man.

The segregation of the human peptidase-C phenotype in five different series of human-mouse hybrid clones was examined. The chromosome constitution of these hybrids was determined by quinacrine mustard fluorescence, Giemsa banding, and constitutive heterochromatin staining. That the clones could be classified without exception either as human peptidase C positive/ A-1 positive (14 clones), or as peptidase C negative/ A-1 negative (12 clones) indicates that peptidase C can be assigned to the human A-i chromosome. Data from an extensive series of human-mouse clones used provide support for the syntenic association between peptidase C and phosphoglucomutase-1 and by inference a linkage of both to Rh factor group.

Animals↗

PubMed1987

Transport and phosphorylation of disaccharides by the ruminal bacterium Streptococcus bovis.

Toluene-treated cells of Streptococcus bovis JB1 phosphorylated cellobiose, glucose, maltose, and sucrose by the phosphoenolpyruvate-dependent phosphotransferase system. Glucose phosphorylation was constitutive, while all three disaccharide systems were inducible. Competition experiments indicated that separate phosphotransferase systems (enzymes II) existed for glucose, maltose, and sucrose. [14C]maltose transport was inhibited by excess (10 mM) glucose and to a lesser extent by sucrose (90 and 46%, respectively). [14C]glucose and [14C]sucrose transports were not inhibited by an excess of maltose. Since [14C]maltose phosphorylation in triethanolamine buffer was increased 160-fold as the concentration of Pi was increased from 0 to 100 mM, a maltose phosphorylase (Km for Pi, 9.5 mM) was present, and this activity was inducible. Maltose was also hydrolyzed by an inducible maltase. Glucose 1-phosphate arising from the maltose phosphorylase was metabolized by a constitutive phosphoglucomutase that was specific for alpha-glucose 1-phosphate (Km, 0.8 mM). Only sucrose-grown cells possessed sucrose hydrolase activity (Km, 3.1 mM), and this activity was much lower than the sucrose phosphotransferase system and sucrose-phosphate hydrolase activities.

Animals↗

PubMed1989

beta-Glucose-1-Phosphate, a Possible Mediator for Polysaccharide Formation in Maltose-Assimilating Lactococcus lactis.

Homolactic fermentation of glucose and heterolactic fermentation of maltose with Lactococcus lactis 65.1 were confirmed. When moles of glucose were compared, the uptake rates of the two carbon sources were similar. The intracellular concentration of fructose-1,6-diphosphate (FDP) in maltose-assimilating cells was half of that in glucose-assimilating cells. Similarly, formation of FDP and lactate from maltose by extracts of maltose-grown cells was half of that formed from glucose by extracts of glucose-grown cells, indicating a difference in the utilization of the two carbon sources for energy metabolism. Concentrations of adenine nucleotides were similar in both types of cells. Glucose-1-phosphate was found in extracts of maltose-grown cells given maltose and, in addition, an inducible and low beta-specific phosphoglucomutase activity was observed. beta-Glucose-1-phosphate was not metabolized by cell extracts to either FDP or lactate, suggesting an alternative metabolic route. The amount of [C]maltose incorporated into the cell material of maltose-grown cells was four times greater than that of [C]glucose incorporated into the cell material of glucose-grown cells. The intracellular concentration of UTP was lower in maltose-assimilating cells than in glucose-assimilating cells. Cells grown on maltose were more spherical and less fragile than cells grown on glucose.

Journal Article↗

PubMed1994

Carbon Metabolism Enzymes of Rhizobium tropici Cultures and Bacteroids.

We determined the activities of selected enzymes involved in carbon metabolism in free-living cells of Rhizobium tropici CFN299 grown in minimal medium with different carbon sources and in bacteroids of the same strain. The set of enzymatic activities in sucrose-grown cells suggests that the pentose phosphate pathway, with the participation of the Entner-Doudoroff pathway, is probably the primary route for sugar catabolism. In glutamate- and malate-grown cells, high activities of the gluconeogenic enzymes (phosphoenolpyruvate carboxykinase, fructose-6-phosphate aldolase, and fructose bisphosphatase) were detected. In bacteroids, isolated in Percoll gradients, the levels of activity for many of the enzymes measured were similar to those of malate-grown cells, except that higher activities of glucokinase, glucose-6-phosphate dehydrogenase, and NAD-dependent phosphogluconate dehydrogenase were detected. Phosphoglucomutase and UDP glucose pyrophosphorylase showed high and constant levels under all growth conditions and in bacteroids.

Journal Article↗

PubMed1996

Isozyme Variation among Biological Species in the Gibberella fujikuroi Species Complex (Fusarium Section Liseola).

Isozyme phenotypes were determined for 101 strains of Gibberella fujikuroi and 2 strains of Gibberella nygamai that represent seven biological species (mating populations) isolated from a variety of plant hosts in dispersed geographic locations. Fourteen enzymes were resolved in one or more of three buffer systems. Two of the enzymes, arylesterase and acid phosphatase, were polymorphic within two or more biological species and are suitable for intraspecific studies of population variation. Six enzymes, alcohol dehydrogenase, aspartate aminotransferase, glucose-6-phosphate dehydrogenase, mannitol dehydrogenase, phosphoglucomutase, and phosphogluconate dehydrogenase, were monomorphic in all of the isolates examined. The remaining six enzymes, fumarase, glucose phosphate isomerase, glutamate dehydrogenase (NADP), isocitrate dehydrogenase (NADP), malate dehydrogenase, and triose-phosphate isomerase, could potentially be used to distinguish the different biological species. Mating populations C and D are the most similar, since the mating population C isolates examined had the same isozyme phenotype as did a subset of the isolates in mating population D. Mating population E is the least similar to the other taxa examined. Unique isozyme phenotypes are present but are composed of banding patterns shared among the biological species. This finding supports the hypothesis that these biological species, with the possible exception of mating populations C and D, are reproductively isolated from one another and that no significant gene flow is occurring between them. Isozyme analysis is a useful method to distinguish these closely related biological species. Examination of isozyme phenotypes is more rapid than the present technique, which is based on sexual crosses; can be applied to strains that are not sexually fertile; and is more sensitive than traditional morphological characters, which cannot distinguish more than three or four morphological groups among the seven biological species. While emphasizing the discreteness of the mating populations as biological entities, our isozyme data also reaffirm the close genetic relationship among these groups.

Journal Article↗

PubMed1997

Growth and energetics of Leuconostoc mesenteroides NRRL B-1299 during metabolism of various sugars and their consequences for dextransucrase production.

The metabolic and energetic properties of Leuconostoc mesenteroides have been examined with the goal of better understanding the parameters which affect dextransucrase activity and hence allowing the development of strategies for improved dextransucrase production. Glucose and fructose support equivalent specific growth rates (0.6 h-1) under aerobic conditions, but glucose leads to a better biomass yield in anaerobiosis. Both sugars are phosphorylated by specific hexokinases and catabolized through the heterofermentative phosphoketolase pathway. During sucrose-grown cultures, a large fraction of sucrose is converted outside the cell by dextransucrase into dextran and fructose and does not support growth. The other fraction enters the cell, where it is phosphorylated by an inducible sucrose phosphorylase and converted to glucose-6-phosphate (G-6-P) by a constitutive phosphoglucomutase and to heterofermentative products (lactate, acetate, and ethanol). Sucrose supports a higher growth rate (0.98 h-1) than the monosaccharides. When fructose is not consumed simultaneously with G-1-P, the biomass yield relative to ATP is high (16.8 mol of ATP.mol of sucrose-1), and dextransucrase production is directly proportional to growth. However, when the fructose moiety is used, a sink of energy is observed, and dextransucrase production is no longer correlated with growth. As a consequence, fructose catabolism must be avoided to improve the amount of dextransucrase synthesized.

Adenosine Triphosphate↗