Journal articles: 'Maltose Analysis'

1

Vongsangnak, Wanwipa, Margarita Salazar, Kim Hansen, and Jens Nielsen. "Genome-wide analysis of maltose utilization and regulation in aspergilli." Microbiology 155, no. 12 (December 1, 2009): 3893–902. http://dx.doi.org/10.1099/mic.0.031104-0.

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Maltose utilization and regulation in aspergilli is of great importance for cellular physiology and industrial fermentation processes. In Aspergillus oryzae, maltose utilization requires a functional MAL locus, composed of three genes: MALR encoding a regulatory protein, MALT encoding maltose permease and MALS encoding maltase. Through a comparative genome and transcriptome analysis we show that the MAL regulon system is active in A. oryzae while it is not present in Aspergillus niger. In order to utilize maltose, A. niger requires a different regulatory system that involves the AmyR regulator for glucoamylase (glaA) induction. Analysis of reporter metabolites and subnetworks illustrates the major route of maltose transport and metabolism in A. oryzae. This demonstrates that overall metabolic responses of A. oryzae occur in terms of genes, enzymes and metabolites when the carbon source is altered. Although the knowledge of maltose transport and metabolism is far from being complete in Aspergillus spp., our study not only helps to understand the sugar preference in industrial fermentation processes, but also indicates how maltose affects gene expression and overall metabolism.

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Charron, M. J., and C. A. Michels. "The naturally occurring alleles of MAL1 in Saccharomyces species evolved by various mutagenic processes including chromosomal rearrangement." Genetics 120, no. 1 (September 1, 1988): 83–93. http://dx.doi.org/10.1093/genetics/120.1.83.

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Abstract In order for a yeast strain to ferment maltose it must contain any one of the five dominant MAL loci. Each dominant MAL locus thus far analyzed contains three genes: GENE 1, encoding maltose permease, GENE 2 encoding maltase and GENE 3 encoding a positive trans-acting regulatory protein. In addition to these dominant MAL loci, several naturally occurring, partially functional alleles of MAL1 and MAL3 have been identified. Here, we present genetic and molecular analysis of the three partially functional alleles of MAL1: the MAL1p allele which can express only the MAL activator; the MAL1 g allele which can express both a maltose permease and maltase; and the mal1(0) allele which can express only maltase. Based on our results, we propose that the MAL1p, MAL1g and mal1(0) alleles evolved from the dominant MAL1 locus by a series of rearrangements and/or deletions of this yeast telomere-associated locus as well as by other mutagenic processes of gene inactivation. One surprising finding is that the MAL1g-encoded maltose permease exhibits little sequence homology to the MAL1-encoded maltose permease though they appear to be functionally homologous.

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Day, Rachel E., Peter J. Rogers, Ian W. Dawes, and Vincent J. Higgins. "Molecular Analysis of Maltotriose Transport and Utilization by Saccharomycescerevisiae." Applied and Environmental Microbiology 68, no. 11 (November 2002): 5326–35. http://dx.doi.org/10.1128/aem.68.11.5326-5335.2002.

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ABSTRACT Efficient fermentation of maltotriose is a desired property of Saccharomyces cerevisiae for brewing. In a standard wort, maltotriose is the second most abundant sugar, and slower uptake leads to residual maltotriose in the finished product. The limiting factor of sugar metabolism is its transport, and there are conflicting reports on whether a specific maltotriose permease exists or whether the mechanisms responsible for maltose uptake also carry out maltotriose transport. In this study, radiolabeled maltotriose was used to show that overexpression of the maltose permease gene, MAL61, in an industrial yeast strain resulted in an increase in the rate of transport of maltotriose as well as maltose. A strain derived from W303-1A and lacking any maltose or maltotriose transporter but carrying a functional maltose transport activator (MAL63) was developed. By complementing this strain with permeases encoded by MAL31, MAL61, and AGT1, it was possible to measure their specific transport kinetics by using maltotriose and maltose. All three permeases were capable of high-affinity transport of maltotriose and of allowing growth of the strain on the sugar. Maltotriose utilization from the permease encoded by AGT1 was regulated by the same genetic mechanisms as those involving the maltose transcriptional activator. Competition studies carried out with two industrial strains, one not containing any homologue of AGT1, showed that maltose uptake and maltotriose uptake were competitive and that maltose was the preferred substrate. These results indicate that the presence of residual maltotriose in beer is not due to a genetic or physiological inability of yeast cells to utilize the sugar but rather to the lower affinity for maltotriose uptake in conjunction with deteriorating conditions present at the later stages of fermentation. Here we identify molecular mechanisms regulating the uptake of maltotriose and determine the role of each of the transporter genes in the cells.

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Naumov, G. I., E. S. Naumova, and C. A. Michels. "Genetic variation of the repeated MAL loci in natural populations of Saccharomyces cerevisiae and Saccharomyces paradoxus." Genetics 136, no. 3 (March 1, 1994): 803–12. http://dx.doi.org/10.1093/genetics/136.3.803.

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Abstract In Saccharomyces cerevisiae, the gene functions required to ferment the disaccharide maltose are encoded by the MAL loci. Any one of five highly sequence homologous MAL loci identified in various S. cerevisiae strains (called MAL1, 2, 3, 4 and 6) is sufficient to ferment maltose. Each is a complex of three genes encoding maltose permease, maltase and a transcription activator. This family of loci maps to telomere-linked positions on different chromosomes and most natural strains contain more than one MAL locus. A number of naturally occurring, mutant alleles of MAL1 and MAL3 have been characterized which lack one or more of the gene functions encoded by the fully functional MAL loci. Loss of these gene functions appears to have resulted from mutation and/or rearrangement within the locus. Studies to date concentrated on the standard maltose fermenting strains of S. cerevisiae available from the Berkeley Yeast Stock Center collection. In this report we extend our genetic analysis of the MAL loci to a number of maltose fermenting and nonfermenting natural strains of S. cerevisiae and Saccharomyces paradoxus. No new MAL loci were discovered but several new mutant alleles of MAL1 were identified. The evolution of this gene family is discussed.

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Hu, Zhen, Yingzi Yue, Hua Jiang, Bin Zhang, Peter W. Sherwood, and Corinne A. Michels. "Analysis of the Mechanism by Which Glucose Inhibits Maltose Induction of MAL Gene Expression in Saccharomyces." Genetics 154, no. 1 (January 1, 2000): 121–32. http://dx.doi.org/10.1093/genetics/154.1.121.

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Abstract Expression of the MAL genes required for maltose fermentation in Saccharomyces cerevisiae is induced by maltose and repressed by glucose. Maltose-inducible regulation requires maltose permease and the MAL-activator protein, a DNA-binding transcription factor encoded by MAL63 and its homologues at the other MAL loci. Previously, we showed that the Mig1 repressor mediates glucose repression of MAL gene expression. Glucose also blocks MAL-activator-mediated maltose induction through a Mig1p-independent mechanism that we refer to as glucose inhibition. Here we report the characterization of this process. Our results indicate that glucose inhibition is also Mig2p independent. Moreover, we show that neither overexpression of the MAL-activator nor elimination of inducer exclusion is sufficient to relieve glucose inhibition, suggesting that glucose acts to inhibit induction by affecting maltose sensing and/or signaling. The glucose inhibition pathway requires HXK2, REG1, and GSF1 and appears to overlap upstream with the glucose repression pathway. The likely target of glucose inhibition is Snf1 protein kinase. Evidence is presented indicating that, in addition to its role in the inactivation of Mig1p, Snf1p is required post-transcriptionally for the synthesis of maltose permease whose function is essential for maltose induction.

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Charron, M. J., R. A. Dubin, and C. A. Michels. "Structural and functional analysis of the MAL1 locus of Saccharomyces cerevisiae." Molecular and Cellular Biology 6, no. 11 (November 1986): 3891–99. http://dx.doi.org/10.1128/mcb.6.11.3891-3899.1986.

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We describe the isolation of a 22.6-kilobase fragment of DNA containing the MAL1 locus of Saccharomyces cerevisiae. Our results demonstrate that the MAL1 locus, like the MAL6 locus, is a complex locus containing three genes. These genes were organized similarly to their MAL6 counterparts. We refer to them as MAL11, MAL12, and MAL13 and show that they are functionally homologous to the MAL61 (encoding maltose permease), MAL62 (encoding maltase), and MAL63 (encoding the positive regulator) genes of the MAL6 locus. Transcription from each of the three genes was analyzed in a strain carrying the undisrupted MAL1 locus and in strains carrying single disruptions in each of the MAL1 genes. The MAL1 and MAL1 loci were found to be highly sequence homologous and conserved throughout the region containing these three genes. The strain used to isolate the MAL1 locus also carried the tightly linked SUC1 gene. The SUC1 gene was found to be located on the same 22.6-kilobase fragment containing the MAL1 locus and 5 kilobases from the 3' end of the MAL12 gene. The meaning of these results with regard to the mechanism of regulation of maltose fermentation is discussed.

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7

Charron, M. J., R. A. Dubin, and C. A. Michels. "Structural and functional analysis of the MAL1 locus of Saccharomyces cerevisiae." Molecular and Cellular Biology 6, no. 11 (November 1986): 3891–99. http://dx.doi.org/10.1128/mcb.6.11.3891.

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We describe the isolation of a 22.6-kilobase fragment of DNA containing the MAL1 locus of Saccharomyces cerevisiae. Our results demonstrate that the MAL1 locus, like the MAL6 locus, is a complex locus containing three genes. These genes were organized similarly to their MAL6 counterparts. We refer to them as MAL11, MAL12, and MAL13 and show that they are functionally homologous to the MAL61 (encoding maltose permease), MAL62 (encoding maltase), and MAL63 (encoding the positive regulator) genes of the MAL6 locus. Transcription from each of the three genes was analyzed in a strain carrying the undisrupted MAL1 locus and in strains carrying single disruptions in each of the MAL1 genes. The MAL1 and MAL1 loci were found to be highly sequence homologous and conserved throughout the region containing these three genes. The strain used to isolate the MAL1 locus also carried the tightly linked SUC1 gene. The SUC1 gene was found to be located on the same 22.6-kilobase fragment containing the MAL1 locus and 5 kilobases from the 3' end of the MAL12 gene. The meaning of these results with regard to the mechanism of regulation of maltose fermentation is discussed.

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8

Woloshuk, C. P., J. R. Cavaletto, and T. E. Cleveland. "Inducers of Aflatoxin Biosynthesis from Colonized Maize Kernels Are Generated by an Amylase Activity from Aspergillus flavus." Phytopathology® 87, no. 2 (February 1997): 164–69. http://dx.doi.org/10.1094/phyto.1997.87.2.164.

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Aflatoxin biosynthesis was induced by compounds in filtrates (EF) obtained from cultures consisting of ground maize kernels colonized by Aspergillus flavus. The inducing activity increased to a maximum at 4 days of incubation and then decreased. Amylase activity was detected in the EF, suggesting that the inducers are products of starch degradation (glucose, maltose, and maltotriose). Analysis of the enzyme by isoelectric focusing electrophoresis indicated a single α-amylase with a pI of 4.3. No maltase or amyloglucosidase was detected in the EF. High-pressure liquid chromatography analysis of the EF indicated the presence of glucose, maltose, and maltotriose in near-equal molar concentrations (about 15 mM). With a β-glucuronidase (GUS) reporter assay consisting of A. flavus transformed with an aflatoxin gene promoter-GUS reporter gene fusion to monitor induction of aflatoxin biosynthesis, the minimum concentration of glucose, maltose, or maltotriose that induced measurable GUS activity was determined to be 1 mM. These results support the hypothesis that the best inducers of aflatoxin biosynthesis are carbon sources readily metabolized via glycolysis. They also suggest that α-amylase produced by A. flavus has a role in the induction of aflatoxin biosynthesis in infected maize kernels.

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9

Vidgren, Virve, Laura Ruohonen, and John Londesborough. "Characterization and Functional Analysis of the MAL and MPH Loci for Maltose Utilization in Some Ale and Lager Yeast Strains." Applied and Environmental Microbiology 71, no. 12 (December 2005): 7846–57. http://dx.doi.org/10.1128/aem.71.12.7846-7857.2005.

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ABSTRACT Maltose and maltotriose are the major sugars in brewer's wort. Brewer's yeasts contain multiple genes for maltose transporters. It is not known which of these express functional transporters. We correlated maltose transport kinetics with the genotypes of some ale and lager yeasts. Maltose transport by two ale strains was strongly inhibited by other α-glucosides, suggesting the use of broad substrate specificity transporters, such as Agt1p. Maltose transport by three lager strains was weakly inhibited by other α-glucosides, suggesting the use of narrow substrate specificity transporters. Hybridization studies showed that all five strains contained complete MAL1, MAL2, MAL3, and MAL4 loci, except for one ale strain, which lacked a MAL2 locus. All five strains also contained both AGT1 (coding a broad specificity α-glucoside transporter) and MAL11 alleles. MPH genes (maltose permease homologues) were present in the lager but not in the ale strains. During growth on maltose, the lager strains expressed AGT1 at low levels and MALx1 genes at high levels, whereas the ale strains expressed AGT1 at high levels and MALx1 genes at low levels. MPHx expression was negligible in all strains. The AGT1 sequences from the ale strains encoded full-length (616 amino acid) polypeptides, but those from both sequenced lager strains encoded truncated (394 amino acid) polypeptides that are unlikely to be functional transporters. Thus, despite the apparently similar genotypes of these ale and lager strains revealed by hybridization, maltose is predominantly carried by AGT1-encoded transporters in the ale strains and by MALx1-encoded transporters in the lager strains.

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Chinappi, Mauro, Fabio Cecconi, and Carlo Massimo Casciola. "Computational analysis of maltose binding protein translocation." Philosophical Magazine 91, no. 13-15 (May 2011): 2034–48. http://dx.doi.org/10.1080/14786435.2011.557670.

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11

Jansen, Mickel L. A., Pascale Daran-Lapujade, Johannes H. de Winde, Matthew D. W. Piper, and Jack T. Pronk. "Prolonged Maltose-Limited Cultivation of Saccharomyces cerevisiae Selects for Cells with Improved Maltose Affinity and Hypersensitivity." Applied and Environmental Microbiology 70, no. 4 (April 2004): 1956–63. http://dx.doi.org/10.1128/aem.70.4.1956-1963.2004.

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ABSTRACT Prolonged cultivation (>25 generations) of Saccharomyces cerevisiae in aerobic, maltose-limited chemostat cultures led to profound physiological changes. Maltose hypersensitivity was observed when cells from prolonged cultivations were suddenly exposed to excess maltose. This substrate hypersensitivity was evident from massive cell lysis and loss of viability. During prolonged cultivation at a fixed specific growth rate, the affinity for the growth-limiting nutrient (i.e., maltose) increased, as evident from a decreasing residual maltose concentration. Furthermore, the capacity of maltose-dependent proton uptake increased up to 2.5-fold during prolonged cultivation. Genome-wide transcriptome analysis showed that the increased maltose transport capacity was not primarily due to increased transcript levels of maltose-permease genes upon prolonged cultivation. We propose that selection for improved substrate affinity (ratio of maximum substrate consumption rate and substrate saturation constant) in maltose-limited cultures leads to selection for cells with an increased capacity for maltose uptake. At the same time, the accumulative nature of maltose-proton symport in S. cerevisiae leads to unrestricted uptake when maltose-adapted cells are exposed to a substrate excess. These changes were retained after isolation of individual cell lines from the chemostat cultures and nonselective cultivation, indicating that mutations were involved. The observed trade-off between substrate affinity and substrate tolerance may be relevant for metabolic engineering and strain selection for utilization of substrates that are taken up by proton symport.

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JHA, PRIYAMVADA, VINEET KUMAR, ANITA RANI, and ANIL KUMAR. "Mapping QTLs controlling the biosynthesis of maltose in soybean." Romanian Biotechnological Letters 26, no. 5 (September 20, 2021): 2936–41. http://dx.doi.org/10.25083/rbl/26.5/2936.2941.

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The present study was carried out to identify genomic regions associated with maltose in 2 F2 populations through assessment of sugars using HPLC and genotyping using SSR markers across the genome. SSR markers, Sat_216 (chr 12) and Satt681 (chr 6) in F2 population I and Sat_105 (chr 20) in F2 population II showed significant (P< 0.5) association with maltose content through single marker analysis (SMA) with LOD score of 3.18 (R2 =9.7), 2.54 (R2 =6.8), and 3.54 (R2 =10.4), respectively. Composite interval mapping analysis (CIM) let to identify different QTLs (other than SMA) for maltose content on chr 11, chr 13 and chr 17 in F2 population I while chr 6 and chr15 in F2 population II. QTLs identified for maltose content are in proximity of known functional genes responsible for degradation of starch into maltose. QTLs identified for maltose in the study may be deployed for improving efficiency of marker assisted breeding for development of soybean genotypes with high levels of this sugar.

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Ha, S. N., L. J. Madsen, and J. W. Brady. "Conformational analysis and molecular dynamics simulations of maltose." Biopolymers 27, no. 12 (December 1988): 1927–52. http://dx.doi.org/10.1002/bip.360271207.

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Van Leeuwen, C. C. M., R. A. Weusthuis, E. Postma, P. J. A. Van den Broek, and J. P. Van Dijken. "Maltose/proton co-transport in Saccharomyces cerevisiae. Comparative study with cells and plasma membrane vesicles." Biochemical Journal 284, no. 2 (June 1, 1992): 441–45. http://dx.doi.org/10.1042/bj2840441.

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Maltose/proton co-transport was studied in intact cells and in plasma membrane vesicles of the yeast Saccharomyces cerevisiae. In order to determine uphill transport in vesicles, plasma membranes were fused with proteoliposomes containing cytochrome c oxidase as a proton-motive force-generating system. Maltose accumulation, dependent on the electrical and pH gradients, was observed. The initial uptake velocity and accumulation ratio in vesicles proved to be dependent on the external pH. Moreover, kinetic analysis of maltose transport showed that Vmax. values greatly decreased with increasing pH, whereas the Km remained virtually constant. These observations were in good agreement with results obtained with intact cells, and suggest that proton binding to the carrier proceeds with an apparent pK of 5.7. The observation with intact cells that maltose is co-transported with protons in a one-to-one stoichiometry was ascertained in the vesicle system by measuring the balance between proton-motive force and the chemical maltose gradient. These results show that maltose transport in vesicles prepared by fusion of plasma membranes with cytochrome c oxidase proteoliposomes behaves in a similar way as in intact cells. It is therefore concluded that this vesicle model system offers a wide range of new possibilities for the study of maltose/proton co-transport in more detail.

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Kohno, Masaki, Takatoshi Arakawa, Naoki Sunagawa, Tetsuya Mori, Kiyohiko Igarashi, Tomoyuki Nishimoto, and Shinya Fushinobu. "Molecular analysis of cyclic α-maltosyl-(1→6)-maltose binding protein in the bacterial metabolic pathway." PLOS ONE 15, no. 11 (November 19, 2020): e0241912. http://dx.doi.org/10.1371/journal.pone.0241912.

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Cyclic α-maltosyl-(1→6)-maltose (CMM) is a cyclic glucotetrasaccharide with alternating α-1,4 and α-1,6 linkages. Here, we report functional and structural analyses on CMM-binding protein (CMMBP), which is a substrate-binding protein (SBP) of an ABC importer system of the bacteria Arthrobacter globiformis. Isothermal titration calorimetry analysis revealed that CMMBP specifically bound to CMM with a Kd value of 9.6 nM. The crystal structure of CMMBP was determined at a resolution of 1.47 Å, and a panose molecule was bound in a cleft between two domains. To delineate its structural features, the crystal structure of CMMBP was compared with other SBPs specific for carbohydrates, such as cyclic α-nigerosyl-(1→6)-nigerose and cyclodextrins. These results indicate that A. globiformis has a unique metabolic pathway specialized for CMM.

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Nelson, Bryn D., and Beth Traxler. "Exploring the Role of Integral Membrane Proteins in ATP-Binding Cassette Transporters: Analysis of a Collection of MalG Insertion Mutants." Journal of Bacteriology 180, no. 9 (May 1, 1998): 2507–14. http://dx.doi.org/10.1128/jb.180.9.2507-2514.1998.

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ABSTRACT The maltose transport complex of Escherichia coli is a well-studied example of an ATP-binding cassette transporter. The complex, containing one copy each of the integral membrane proteins MalG and MalF and two copies of the peripheral cytoplasmic membrane protein MalK, interacts with the periplasmic maltose-binding protein to efficiently translocate maltose and maltodextrins across the bacterial cytoplasmic membrane. To investigate the role of MalG both in MalFGK2 assembly interactions and in subsequent transport interactions, we isolated and characterized 18 different MalG mutants, each containing a 31-residue insertion in the protein. Eight insertions mapping to distinct hydrophilic regions of MalG permitted either assembly or both assembly and transport interactions to occur. In particular, we isolated two insertions mapping to extracytoplasmic (periplasmic) regions of MalG which preserved both assembly and transport abilities, suggesting that these are permissive sites in the protein. Another periplasmic insertion seems to affect only transport-specific interactions between MalG and maltose-binding protein, defining a novel class of MalG mutants. Finally, four MalG mutant proteins, although stably expressed, are unable to assemble into the MalFGK2 complex. These mutants contain insertions in only two different hydrophilic regions of MalG, consistent with the notion that a restricted number of domains in this protein are critical complex assembly determinants. These MalG mutants will allow us to further explore the intermolecular interactions of this model transporter.

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Bellon-Maurel, Véronique, Céline Vallat, and Darrell Goffinet. "Quantitative Analysis of Individual Sugars during Starch Hydrolysis by FT-IR/ATR Spectrometry. Part I: Multivariate Calibration Study—Repeatibility and Reproducibility." Applied Spectroscopy 49, no. 5 (May 1995): 556–62. http://dx.doi.org/10.1366/0003702953964002.

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This paper discusses the use of Fourier transform infrared (FT-IR) spectroscopy coupled with an attenuated total reflectance (ATR) accessory as applied to the quantification of individual sugar concentrations (glucose, maltose, maltotriose, and maltodextrines) in real mixtures extracted during starch hydrolysis. Solutions studied contained dry matter ranging between 250 and 300 g/kg. Glucose and maltose were detected with the required precision, but not maltotriose or maltodextrines. The measurements are fairly repeatible, and predictions are reproducible.

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Bentrup, K. H. z., R. Schmid, and E. Schneider. "Maltose transport in Aeromonas hydrophila: purification, biochemical characterization and partial protein sequence analysis of a periplasmic maltose-binding protein." Microbiology 140, no. 4 (April 1, 1994): 945–51. http://dx.doi.org/10.1099/00221287-140-4-945.

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Nguyen, Duyen Dang My, and Le Thi Pham. "Effect of monosaccharides and disaccharides on the retrogradation of tapioca starch gel." Science and Technology Development Journal 19, no. 4 (December 31, 2016): 50–63. http://dx.doi.org/10.32508/stdj.v19i4.618.

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Gelatinization of tapioca starch is retrograded during the frozen – storage. This retrogradation affects the quality of the starchy food. This paper studied the influence of various types of sugars: glucose, fructose, sucrose and maltose in different concentrations: 0 %, 2 %, 4 %, 6 %, 8 % (w/w) on the stability of tapioca starch gels over 5 freeze – thaw cycles. The syneresis, turbidity (OD) and the hydrolysis degree by apha–amylase of starch gels were determined to analysis the effect of sugars on the stability of the tapioca starch gels. Our result showed that the freeze – thaw stability of tapioca starch gels could be improved by adding sugars. The improvement of the syneresis (%) was in the order: maltose > sucrose > glucose > fructose. The result also showed that disaccharides (sucrose, maltose) were more effective than monosaccharides (glucose and fructose) in reducing the syneresis and turbidity. Adding maltose at 8 % (w/w) was the most effective in the reduction of the starch retrogradation

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Mirouze, F. De Lène, J. C. Boulou, N. Dupuy, M. Meurens, J. P. Huvenne, and P. Legrand. "Quantitative Analysis of Glucose Syrups by ATR/FT-IR Spectroscopy." Applied Spectroscopy 47, no. 8 (August 1993): 1187–91. http://dx.doi.org/10.1366/0003702934067946.

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Thanks to what has been achieved by the Fourier transform, infrared spectrometry can now become a state-of-the-art device in quality control laboratories if we consider its precision and the gain in time it ensures in comparison to results from traditional analytical methods such as chromatography. Moreover, the increasing number of new mathematical regression methods such as Partial Least-Squares (PLS) regression allows multicomponent quantitative analysis in mixtures. For instance, the analysis of the three main components (glucose, maltose, and fructose) of the dry substance which represents about 70% (w/v) in glucose syrups can be done with the use of Attenuated Total Reflectance (ATR) spectroscopy with a precision in the region of 3 to 5%, whereas the time required to obtain an analysis report is about five minutes. The high similarity between the glucose and the maltose may make the analysis difficult.

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Nguyen, Tu N., Arvin D. Ejaz, Mark A. Brancieri, Amy M. Mikula, Karen E. Nelson, Steven R. Gill, and Kenneth M. Noll. "Whole-Genome Expression Profiling of Thermotoga maritima in Response to Growth on Sugars in a Chemostat." Journal of Bacteriology 186, no. 14 (July 15, 2004): 4824–28. http://dx.doi.org/10.1128/jb.186.14.4824-4828.2004.

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ABSTRACT To provide data necessary to study catabolite-linked transcriptional networks in Thermotoga maritima, we used full-genome DNA microarray analysis of global transcriptional responses to growth on glucose, lactose, and maltose in a chemostat. A much larger number of genes changed expression in cells grown on lactose than on maltose, each relative to genes expressed in cells grown on glucose. Genes encoding putative oligopeptide transporters were often coregulated with adjacent glycosidase-encoding genes. Genes encoding enzymes catalyzing NADH oxidation were up-regulated on both lactose and maltose. Genes involved in iron and sulfur metabolism were differentially expressed in response to lactose. These data help define the sets of coregulated genes and suggest possible functions for their encoded products.

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Kijima, H., K. Nagata, A. Nishiyama, and H. Morita. "Receptor current fluctuation analysis in the labellar sugar receptor of the fleshfly." Journal of General Physiology 91, no. 1 (January 1, 1988): 29–47. http://dx.doi.org/10.1085/jgp.91.1.29.

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Fluctuations in the receptor current of the labellar sugar receptor of the fleshfly were analyzed. The receptor current was recorded extracellularly as a drop in potential between the tip and the base of the taste sensillum. After treatment with tetrodotoxin, the taste cells completely lost their impulses but retained their receptor currents, thus facilitating analysis of the receptor current without disturbance by impulses. The current fluctuation increased markedly when the sensillum was stimulated with effective sugars: maltose, sucrose, and fructose. The fluctuation increased in parallel with development of the receptor current, which indicates that it occurs as soon as the sugar reaches the apex of the sensory process. Analysis of fluctuations by computation of autocorrelation functions (ACFs) or power spectra (PS) revealed that: (a) the variance (mean square) of fluctuation vs. sugar concentration curve reached a maximum, in contrast to the monotonic increase shown by the receptor current; (b) the ACF was approximated by an exponential term, and its time constant differed according to the sugars used and their concentrations. The time constants for fructose and maltose decreased with increases in sugar concentration. At the concentrations of sugars evoking the same magnitude of receptor current, the time constant for fructose was the largest and that for maltose was the smallest. It was strongly suggested that transduction ion channels are present at the tip region of the sensory process of the sugar receptor cell and are operated directly by sugars.

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Lo Leggio, Leila, Florence Dal Degan, Peter Poulsen, Susanne Oxenbøll Sørensen, Kenneth Harlow, Pernille Harris, and Sine Larsen. "Crystallization and preliminary X-ray analysis of maltose O-acetyltransferase." Acta Crystallographica Section D Biological Crystallography 57, no. 12 (November 21, 2001): 1915–18. http://dx.doi.org/10.1107/s0907444901016298.

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Ryoo, Nayeon, Joon-Seob Eom, Hyun-Bi Kim, Bich Thuy Vo, Sang-Won Lee, Tae-Ryong Hahn, and Jong-Seong Jeon. "Expression and functional analysis of rice plastidic maltose transporter, OsMEX1." Journal of the Korean Society for Applied Biological Chemistry 56, no. 2 (April 2013): 149–55. http://dx.doi.org/10.1007/s13765-012-3266-z.

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Mishra, Vineet, Priyankur Roy, Khushali Gandhi, Sumesh Choudhary, Rohina Aggarwal, and Shaheen Hokabaj. "Safety and Efficacy of Intravenous Ferric Carboxy Maltose in Iron Deficiency Anaemia During Postpartum Period." Journal of Nepal Health Research Council 15, no. 3 (January 1, 2018): 208–11. http://dx.doi.org/10.3126/jnhrc.v15i3.18841.

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Background: Iron deficiency is the commonest treatable cause of postpartum anaemia. Parenteral iron therapy results in faster and higher replenishment of iron stores and correction of haemoglobin levels with better compliance. Ferric Carboxy Maltose is an effective and a safe option which can be administered intravenously in single total correction dose without any serious adverse effects.The study was done to evaluate the efficacy and safety of Ferric Carboxy Maltose in the treatment of iron deficiency anaemia in post-natal patients.Methods: It was an open, single arm study including 615 women with diagnosis of Iron deficiency anaemia and haemoglobin (Hb) levels between 4gm% and 11gm% from January 2013 to December 2016. Intravenous Ferric Carboxy Maltose(500-1500mg) was administered and the improvement in haemoglobin levels and iron stores were assessed after three weeks of total dose infusion.Results: Out of the 615 women, 595 women were included in the analysis. Most of the women were in the age group of 27-30 years. Most of the women had mild anaemia as per World Health Organisation guidelines. Mean hemoglobin levels significantly increased over a period of three weeks after Ferric Carboxy Maltose administration. Other parameters like total iron binding capacity, Ferritin and Iron also had a significant improvement after Ferric Carboxy Maltose administration. No serious adverse events were observed after Ferric Carboxy Maltose.Conclusions: Intravenous Ferric Carboxy Maltose was an effective and a safe treatment option for iron deficiency anaemia and has an advantage of single administration of high doses without serious adverse effects.

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Lee, Han-Seung, Keith R. Shockley, Gerrit J. Schut, Shannon B. Conners, Clemente I. Montero, Matthew R. Johnson, Chung-Jung Chou, et al. "Transcriptional and Biochemical Analysis of Starch Metabolism in the Hyperthermophilic Archaeon Pyrococcus furiosus." Journal of Bacteriology 188, no. 6 (March 15, 2006): 2115–25. http://dx.doi.org/10.1128/jb.188.6.2115-2125.2006.

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ABSTRACT Pyrococcus furiosus utilizes starch and its degradation products, such as maltose, as primary carbon sources, but the pathways by which these α-glucans are processed have yet to be defined. For example, its genome contains genes proposed to encode five amylolytic enzymes (including a cyclodextrin glucanotransferase [CGTase] and amylopullulanase), as well as two transporters for maltose and maltodextrins (Mal-I and Mal-II), and a range of intracellular enzymes have been purified that reportedly metabolize maltodextrins and maltose. However, precisely which of these enzymes are involved in starch processing is not clear. In this study, starch metabolism in P. furiosus was examined by biochemical analyses in conjunction with global transcriptional response data for cells grown on a variety of glucans. In addition, DNA sequencing led to the correction of two key errors in the genome sequence, and these change the predicted properties of amylopullulanase (now designated PF1935*) and CGTase (PF0478*). Based on all of these data, a pathway is proposed that is specific for starch utilization that involves one transporter (Mal-II [PF1933 to PF1939]) and only three enzymes, amylopullulanase (PF1935*), 4-α-glucanotransferase (PF0272), and maltodextrin phosphorylase (PF1535). Their expression is upregulated on starch, and together they generate glucose and glucose-1-phosphate, which then feed into the novel glycolytic pathway of this organism. In addition, the results indicate that several hypothetical proteins encoded by three gene clusters are also involved in the transport and processing of α-glucan substrates by P. furiosus.

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Spence, Cheryl, W. Greg Wells, and C. Jeffrey Smith. "Characterization of the Primary Starch Utilization Operon in the Obligate Anaerobe Bacteroides fragilis: Regulation by Carbon Source and Oxygen." Journal of Bacteriology 188, no. 13 (July 1, 2006): 4663–72. http://dx.doi.org/10.1128/jb.00125-06.

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ABSTRACT The opportunistic pathogen Bacteroides fragilis is a commensal organism in the large intestine, where it utilizes both dietary and host-derived polysaccharides as a source of carbon and energy. In this study, a four-gene operon required for starch utilization was identified. The operon also was found to be oxygen responsive and thus was designated osu for oxygen-induced starch utilization. The first three genes in the operon were predicted to encode outer membrane proteins involved in starch binding, and a fourth gene, osuD, encoded an amylase involved in starch hydrolysis. Insertional mutation of the osuA gene (ΩosuA) resulted in the inability to utilize starch or glycogen and an insertional mutation into the osuD gene (ΩosuD) was severely impaired for growth on starch media. Transcriptional studies indicated that maltose, maltooligosaccharides, and starch were inducers of osu expression and that maltose was the strongest inducer. A transcriptional activator of osuABCD, OsuR, was identified and found to mediate maltose induction. The ΩosuA and ΩosuD mutants were able to grow on maltose but not starch, whereas a mutation in osuR abolished growth on both substrates, indicating that additional genes under the control of OsuR are needed for maltose utilization. The osuABCD operon also was induced by exposure to oxygen and was shown to be part of the oxidative stress response important for aerotolerance of B. fragilis. Transcriptional analyses showed that osuA was induced 20-fold by oxygen, but OsuR was not required for this activation. Analysis of osu mutants suggested that expression of the operon was important for survival during oxygen exposure but not to hydrogen peroxide stress.

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Viigand, Katrin, Kristina Põšnograjeva, Triinu Visnapuu, and Tiina Alamäe. "Genome Mining of Non-Conventional Yeasts: Search and Analysis of MAL Clusters and Proteins." Genes 9, no. 7 (July 16, 2018): 354. http://dx.doi.org/10.3390/genes9070354.

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Genomic clustering of functionally related genes is rare in yeasts and other eukaryotes with only few examples available. Here, we summarize our data on a nontelomeric MAL cluster of a non-conventional methylotrophic yeast Ogataea (Hansenula) polymorpha containing genes for α-glucosidase MAL1, α-glucoside permease MAL2 and two hypothetical transcriptional activators. Using genome mining, we detected MAL clusters of varied number, position and composition in many other maltose-assimilating non-conventional yeasts from different phylogenetic groups. The highest number of MAL clusters was detected in Lipomyces starkeyi while no MAL clusters were found in Schizosaccharomyces pombe and Blastobotrys adeninivorans. Phylograms of α-glucosidases and α-glucoside transporters of yeasts agreed with phylogenesis of the respective yeast species. Substrate specificity of unstudied α-glucosidases was predicted from protein sequence analysis. Specific activities of Scheffersomycesstipitis α-glucosidases MAL7, MAL8, and MAL9 heterologously expressed in Escherichia coli confirmed the correctness of the prediction—these proteins were verified promiscuous maltase-isomaltases. α-Glucosidases of earlier diverged yeasts L. starkeyi, B. adeninivorans and S. pombe showed sequence relatedness with α-glucosidases of filamentous fungi and bacilli.

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Seibold, Gerd M., Martin Wurst, and Bernhard J. Eikmanns. "Roles of maltodextrin and glycogen phosphorylases in maltose utilization and glycogen metabolism in Corynebacterium glutamicum." Microbiology 155, no. 2 (February 1, 2009): 347–58. http://dx.doi.org/10.1099/mic.0.023614-0.

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Corynebacterium glutamicum transiently accumulates large amounts of glycogen, when cultivated on glucose and other sugars as a source of carbon and energy. Apart from the debranching enzyme GlgX, which is required for the formation of maltodextrins from glycogen, α-glucan phosphorylases were assumed to be involved in glycogen degradation, forming α-glucose 1-phosphate from glycogen and from maltodextrins. We show here that C. glutamicum in fact possesses two α-glucan phosphorylases, which act as a glycogen phosphorylase (GlgP) and as a maltodextrin phosphorylase (MalP). By chromosomal inactivation and subsequent analysis of the mutant, cg1479 was identified as the malP gene. The deletion mutant C. glutamicum ΔmalP completely lacked MalP activity and showed reduced intracellular glycogen degradation, confirming the proposed pathway for glycogen degradation in C. glutamicum via GlgP, GlgX and MalP. Surprisingly, the ΔmalP mutant showed impaired growth, reduced viability and altered cell morphology on maltose and accumulated much higher concentrations of glycogen and maltodextrins than the wild-type during growth on this substrate, suggesting an additional role of MalP in maltose metabolism of C. glutamicum. Further assessment of enzyme activities revealed the presence of 4-α-glucanotransferase (MalQ), glucokinase (Glk) and α-phosphoglucomutase (α-Pgm), and the absence of maltose hydrolase, maltose phosphorylase and β-Pgm, all three known to be involved in maltose utilization by Gram-positive bacteria. Based on these findings, we conclude that C. glutamicum metabolizes maltose via a pathway involving maltodextrin and glucose formation by MalQ, glucose phosphorylation by Glk and maltodextrin degradation via the reactions of MalP and α-Pgm, a pathway hitherto known to be present in Gram-negative rather than in Gram-positive bacteria.

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Zhang, Ran, Yuan T. Pan, Shouming He, Michael Lam, Gary D. Brayer, Alan D. Elbein, and Stephen G. Withers. "Mechanistic Analysis of Trehalose Synthase from Mycobacterium smegmatis." Journal of Biological Chemistry 286, no. 41 (August 12, 2011): 35601–9. http://dx.doi.org/10.1074/jbc.m111.280362.

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Trehalose synthase (TreS) catalyzes the reversible interconversion of maltose and trehalose and has been shown recently to function primarily in the mobilization of trehalose as a glycogen precursor. Consequently, the mechanism of this intriguing isomerase is of both academic and potential pharmacological interest. TreS catalyzes the hydrolytic cleavage of α-aryl glucosides as well as α-glucosyl fluoride, thereby allowing facile, continuous assays. Reaction of TreS with 5-fluoroglycosyl fluorides results in the trapping of a covalent glycosyl-enzyme intermediate consistent with TreS being a member of the retaining glycoside hydrolase family 13 enzyme family, thus likely following a two-step, double displacement mechanism. This trapped intermediate was subjected to protease digestion followed by LC-MS/MS analysis, and Asp230 was thereby identified as the catalytic nucleophile. The isomerization reaction was shown to be an intramolecular process by demonstration of the inability of TreS to incorporate isotope-labeled exogenous glucose into maltose or trehalose consistent with previous studies on other TreS enzymes. The absence of a secondary deuterium kinetic isotope effect and the general independence of kcat upon leaving group ability both point to a rate-determining conformational change, likely the opening and closing of the enzyme active site.

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De Costa, Devika M., Katsunori Suzuki, and Kazuo Yoshida. "Structural and Functional Analysis of a Putative Gene Cluster for Palatinose Transport on the Linear Chromosome of Agrobacterium tumefaciens MAFF301001." Journal of Bacteriology 185, no. 7 (April 1, 2003): 2369–73. http://dx.doi.org/10.1128/jb.185.7.2369-2373.2003.

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ABSTRACT We identified a putative pal gene cluster (palR, palE, palF, palG, palK, palA, and palB) in the plant-tumorigenic bacterium Agrobacterium tumefaciens MAFF301001; by sequencing analyses, this cluster was found to be involved in palatinose transport, and its functional importance was revealed by mutational analyses. The pal gene products were highly homologous to those of putative trehalose/maltose ABC-type transport systems but were not essential to bacterial growth on trehalose. Insertion mutations in the palK and palE genes showed the necessity of these genes for bacterial growth and chemotaxis with palatinose as the carbon source, but no inhibition of tumorigenesis was observed. Growth on trehalose and maltose was not influenced by the mutations.

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32

Lorquet, Frédérique, Philippe Goffin, Lidia Muscariello, Jean-Bernard Baudry, Victor Ladero, Margherita Sacco, Michiel Kleerebezem, and Pascal Hols. "Characterization and Functional Analysis of the poxB Gene, Which Encodes Pyruvate Oxidase in Lactobacillus plantarum." Journal of Bacteriology 186, no. 12 (June 15, 2004): 3749–59. http://dx.doi.org/10.1128/jb.186.12.3749-3759.2004.

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ABSTRACT The pyruvate oxidase gene (poxB) from Lactobacillus plantarum Lp80 was cloned and characterized. Northern blot and primer extension analyses revealed that transcription of poxB is monocistronic and under the control of a vegetative promoter. poxB mRNA expression was strongly induced by aeration and was repressed by glucose. Moreover, Northern blotting performed at different stages of growth showed that poxB expression is maximal in the early stationary phase when glucose is exhausted. Primer extension and in vivo footprint analyses revealed that glucose repression of poxB is mediated by CcpA binding to the cre site identified in the promoter region. The functional role of the PoxB enzyme was studied by using gene overexpression and knockout in order to evaluate its implications for acetate production. Constitutive overproduction of PoxB in L. plantarum revealed the predominant role of pyruvate oxidase in the control of acetate production under aerobic conditions. The ΔpoxB mutant strain exhibited a moderate (20 to 25%) decrease in acetate production when it was grown on glucose as the carbon source, and residual pyruvate oxidase activity that was between 20 and 85% of the wild-type activity was observed with glucose limitation (0.2% glucose). In contrast, when the organism was grown on maltose, the poxB mutation resulted in a large (60 to 80%) decrease in acetate production. In agreement with the latter observation, the level of residual pyruvate oxidase activity with maltose limitation (0.2% maltose) was less than 10% of the wild-type level of activity.

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33

Ojima, Teruyo, Wataru Saburi, Takeshi Yamamoto, and Toshiaki Kudo. "Characterization of Halomonas sp. Strain H11 α-Glucosidase Activated by Monovalent Cations and Its Application for Efficient Synthesis of α-d-Glucosylglycerol." Applied and Environmental Microbiology 78, no. 6 (January 6, 2012): 1836–45. http://dx.doi.org/10.1128/aem.07514-11.

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ABSTRACTAn α-glucosidase (HaG) with the following unique properties was isolated fromHalomonassp. strain H11: (i) high transglucosylation activity, (ii) activation by monovalent cations, and (iii) very narrow substrate specificity. The molecular mass of the purified HaG was estimated to be 58 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). HaG showed high hydrolytic activities toward maltose, sucrose, andp-nitrophenyl α-d-glucoside (pNPG) but to almost no other disaccharides or malto-oligosaccharides higher than trisaccharides. HaG showed optimum activity to maltose at 30°C and pH 6.5. Monovalent cations such as K+, Rb+, Cs+, and NH4+increased the enzymatic activity to 2- to 9-fold of the original activity. These ions shifted the activity-pH profile to the alkaline side. The optimum temperature rose to 40°C in the presence of 10 mM NH4+, although temperature stability was not affected. The apparentKmandkcatvalues for maltose andpNPG were significantly improved by monovalent cations. Surprisingly,kcat/KmforpNPG increased 372- to 969-fold in their presence. HaG used some alcohols as acceptor substrates in transglucosylation and was useful for efficient synthesis of α-d-glucosylglycerol. The efficiency of the production level was superior to that of the previously reported enzymeAspergillus nigerα-glucosidase in terms of small amounts of by-products. Sequence analysis of HaG revealed that it was classified in glycoside hydrolase family 13. Its amino acid sequence showed high identities, 60%, 58%, 57%, and 56%, toXanthomonas campestrisWU-9701 α-glucosidase,Xanthomonas campestrispv. raphani 756C oligo-1,6-glucosidase,Pseudomonas stutzeriDSM 4166 oligo-1,6-glucosidase, andAgrobacterium tumefaciensF2 α-glucosidase, respectively.

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Schut, Gerrit J., Scott D. Brehm, Susmita Datta, and Michael W. W. Adams. "Whole-Genome DNA Microarray Analysis of a Hyperthermophile and an Archaeon: Pyrococcus furiosus Grown on Carbohydrates or Peptides." Journal of Bacteriology 185, no. 13 (July 1, 2003): 3935–47. http://dx.doi.org/10.1128/jb.185.13.3935-3947.2003.

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ABSTRACT The first complete-genome DNA microarray was constructed for a hyperthermophile or a nonhalophilic archaeon by using the 2,065 open reading frames (ORFs) that have been annotated in the genome of Pyrococcus furiosus (optimal growth temperature, 100°C). This was used to determine relative transcript levels in cells grown at 95°C with either peptides or a carbohydrate (maltose) used as the primary carbon source. Approximately 20% (398 of 2065) of the ORFs did not appear to be significantly expressed under either growth condition. Of the remaining 1,667 ORFs, the expression of 125 of them (8%) differed by more than fivefold between the two cultures, and 82 of the 125 (65%) appear to be part of operons, indicating extensive coordinate regulation. Of the 27 operons that are regulated, 5 of them encode (conserved) hypothetical proteins. A total of 18 operons are up-regulated (greater than fivefold) in maltose-grown cells, including those responsible for maltose transport and for the biosynthesis of 12 amino acids, of ornithine, and of citric acid cycle intermediate products. A total of nine operons are up-regulated (greater than fivefold) in peptide-grown cells, including those encoding enzymes involved in the production of acyl and aryl acids and 2-ketoacids, which are used for energy conservation. Analyses of the spent growth media confirmed the production of branched-chain and aromatic acids during growth on peptides. In addition, six nonlinked enzymes in the pathways of sugar metabolism were regulated more than fivefold—three in maltose-grown cells that are unique to the unusual glycolytic pathway and three in peptide-grown cells that are unique to gluconeogenesis. The catalytic activities of 16 metabolic enzymes whose expression appeared to be highly regulated in the two cell types correlated very well with the microarray data. The degree of coordinate regulation revealed by the microarray data was unanticipated and shows that P. furiosus can readily adapt to a change in its primary carbon source.

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35

Ha, Jae-Seok, Jae Jun Song, Young-Mi Lee, Su-Jin Kim, Jung-Hoon Sohn, Chul-Soo Shin, and Seung-Goo Lee. "Design and Application of Highly Responsive Fluorescence Resonance Energy Transfer Biosensors for Detection of Sugar in Living Saccharomyces cerevisiae Cells." Applied and Environmental Microbiology 73, no. 22 (September 21, 2007): 7408–14. http://dx.doi.org/10.1128/aem.01080-07.

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ABSTRACT A protein sensor with a highly responsive fluorescence resonance energy transfer (FRET) signal for sensing sugars in living Saccharomyces cerevisiae cells was developed by combinatorial engineering of the domain linker and the binding protein moiety. Although FRET sensors based on microbial binding proteins have previously been created for visualizing various sugars in vivo, such sensors are limited due to a weak signal intensity and a narrow dynamic range. In the present study, the length and composition of the linker moiety of a FRET-based sensor consisting of CFP-linker1-maltose-binding protein-linker2-YFP were redesigned, which resulted in a 10-fold-higher signal intensity. Molecular modeling of the composite linker moieties, including the connecting peptide and terminal regions of the flanking proteins, suggested that an ordered helical structure was preferable for tighter coupling of the conformational change of the binding proteins to the FRET response. When the binding site residue Trp62 of the maltose-binding protein was diversified by saturation mutagenesis, the Leu mutant exhibited an increased binding constant (82 μM) accompanied by further improvement in the signal intensity. Finally, the maltose sensor with optimized linkers was redesigned to create a sugar sensor with a new specificity and a wide dynamic range. When the optimized maltose sensors were employed as in vivo sensors, highly responsive FRET images were generated from real-time analysis of maltose uptake of Saccharomyces cerevisiae (baker's yeast).

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Chagneau, Claudia, Martine Heyde, Sylvie Alonso, Raymond Portalier, and Patrick Laloi. "External-pH-Dependent Expression of the Maltose Regulon and ompF Gene in Escherichia coli Is Affected by the Level of Glycerol Kinase, Encoded byglpK." Journal of Bacteriology 183, no. 19 (October 1, 2001): 5675–83. http://dx.doi.org/10.1128/jb.183.19.5675-5683.2001.

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ABSTRACT The expression of the maltose system in Escherichia coli is regulated at both transcriptional and translational levels by the pH of the growth medium (pHo). With glycerol as the carbon source, transcription ofmalT, encoding the transcriptional activator of the maltose regulon, is weaker in acidic medium than in alkaline medium. malT transcription became high, regardless of the pHo, when glycerol-3-phosphate or succinate was used as the carbon source. Conversely, malT expression was low, regardless of the pHo, when maltose was used as the carbon source. The increase in malT transcription, associated with the pHo, requires the presence of glycerol in the growth medium and the expression of the glycerol kinase (GlpK). Changes in the level of glpK transcription had a great effect on malT transcription. Indeed, aglpFKX promoter-down mutation has been isolated, and in the presence of this mutation, malTexpression was increased. When glpK was expressed from a high-copy-number plasmid, theglpK-dependent reduced expression of the maltose system became effective regardless of the pHo. Analysis of this repression showed that a malTp1 malTp10 promoter, which is independent of the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex, was no longer repressed by glpFKXamplification. Thus, GlpK-dependent repression of the maltose system requires the cAMP-CRP complex. We propose that the pHo may affect a complex interplay between GlpK, the phosphotransferase-mediated uptake of glucose, and the adenylate cyclase.

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Huawei, Zeng, Wang Chengtao, Qiao Jie, Zhang Bingjing, Zhao Bing, and Dai Chuangyun. "Determining a suitable carbon source for the production of intracellular pigments from Monascus purpureus HBSD 08." Pigment & Resin Technology 48, no. 6 (November 4, 2019): 547–54. http://dx.doi.org/10.1108/prt-05-2019-0042.

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Purpose The Monascus pigment has been widely applied in the food processing industry as a functional additive. Lovastatin and polysaccharides are two important bio-active materials found in Monascus. Citrinin is considered as mycotoxin. Thus, it is important to produce high yields of intracellular Monascus pigments with high yields of lovastatin and polysaccharides, while maintaining low citrinin yields under liquid fermentation. Design/methodology/approach The intracellular yields of pigments, lovastatin, polysaccharides and citrinin; biomass; and reducing the sugar content of Monascus purpureus HBSD 08 were determined every day during a 10-day culturing period using lactose, maltose, sucrose, glucose, glycerine and xylose as the sole carbon sources. Additionally, the pigment composition was analysed by a thin layer chromatography (TLC) and the in vitro antitumor activities of the pigments were determined. Findings The maximal yield of pigments (55.44 U/mL after six days of culture) and lovastatin content (1,475.30 µg/L after five days of culture) were obtained in the presence of glucose and maltose as the sole carbon sources, respectively. The suitable carbon sources for high intracellular polysaccharides yields were sucrose, maltose and xylose. Glucose should not be chosen as the sole carbon source because of its high food safety risk. In vitro antitumor activities of pigments in the presence of different carbon sources were in the order of xylose > glucose = maltose > glycerine > sucrose = lactose. The pigment compositions in the presence of different carbon sources were the same from the TLC analysis. Thus, maltose displayed high intracellular yields of pigments, lovastatin and polysaccharides; high food safety against citrinin, and high in vitro antitumor activity during the ten days culturing period. Originality/value This study shows us the benefits of using maltose as a substrate in the production of intracellular Monascus pigments while ensuring economic and food safety.

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Romaine, Durel J., and Don R. LaBonte. "Heritability Estimates for Sugars, Alcohol Insoluble Solids, and Percent Dry Matter in Baked Sweetpotatoes." HortScience 31, no. 4 (August 1996): 625c—625. http://dx.doi.org/10.21273/hortsci.31.4.625c.

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Narrow-sense heritability (h2) estimates for sugars were determined to assess the feasibility of breeding for a sweeter baked sweetpotato. Roots of parents and half-sib progeny were baked (190°C for 75 minutes) 16 weeks after harvest. Sugars from 10 gram root samples were extracted in ethanol for HPLC sugar quantification. Alcohol insoluble solid (AIS) residues (starch) were also measured from the samples. Dry matter was determined on a separate 10-g sample. Narrow-sense heritability estimates based on variance components analysis for AIS and percent dry matter were 0.20 and 0.32, respectively. Estimates for sugar data were 0.05 for sucrose, 0.52 for maltose, and 0.52 for total sugars (fructose, glucose, sucrose and maltose). These heritability estimates for maltose and total sugars imply a breeder could expect a moderate gain in sweetness over several cycles of selection.

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Bogo, Amauri, and Peter Mantle. "Oligosaccharides in the honeydew of Coccoidea scale insects: Coccus hesperidum L. and a new Stigmacoccus sp. in Brazil." Anais da Sociedade Entomológica do Brasil 29, no. 3 (September 2000): 589–95. http://dx.doi.org/10.1590/s0301-80592000000300022.

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Analysis of the honeydew from an as yet undescribed, though distinctive, Brazilian Stigmacoccus sp. (near S. asper Hempel) by paper chromatography, Fast atom bombardment (FAB-MS) and Gas chromatography-mass spectrometry (GC-MS) identified fructose and glucose as monosaccharides and sucrose, maltose, trehalulose, trehalose and a hexose-hexitol as disaccharides. Erlose and glucosyl erlose have been identified as the tri- and tetra-saccharides in Stigmacoccus sp. and characterised for the first time in scale insects by modern techniques of linkage analysis. The same erlose oligosaccharides were recognised in honeydew of the common scale insect Coccus hesperidum L., together with the pentamer of this series, maltosyl erlose, therefore recognising that specific metabolic transformations of sugars into this oligomeric series occur rather widely in Coccoidea scale insects.

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Colville, C. A., M. J. Seatter, T. J. Jess, G. W. Gould, and H. M. Thomas. "Kinetic analysis of the liver-type (GLUT2) and brain-type (GLUT3) glucose transporters in Xenopus oocytes: substrate specificities and effects of transport inhibitors." Biochemical Journal 290, no. 3 (March 15, 1993): 701–6. http://dx.doi.org/10.1042/bj2900701.

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We have expressed the human isoforms of the liver-type (GLUT2) and brain-type (GLUT3) facilitative glucose transporters in oocytes from Xenopus laevis via injection of in vitro transcribed mRNA. As reported previously [Gould, Thomas, Jess and Bell (1991) Biochemistry 30, 5139-5145], GLUT2 mediates the transport of fructose and galactose, and GLUT3 mediates the transport of galactose. We have examined the effects of D-glucose, D-fructose and maltose on deoxyglucose transport in oocytes expressing GLUT2, and D-glucose, D-galactose and maltose on deoxyglucose transport in oocytes expressing GLUT3, and show that each sugar is a competitive inhibitor of transport. Moreover, D-glucose and maltose competitively inhibit fructose transport by GLUT2 and galactose transport by GLUT3, indicating that the transport of the alternative substrates for these transporters is likely to be mediated by the same outward-facing sugar-binding site used by glucose. Cytochalasin B is a non-competitive inhibitor of glucose transport by the well-characterized GLUT1 isoform. We show here that cytochalasin B is also a non-competitive inhibitor of the transport of deoxyglucose and alternative substrates by GLUT2 and GLUT3 expressed in oocytes. Km and Ki values for each substrate and inhibitor are presented for each isoform, together with further analysis of the binding sites for alternative substrates for these transporter isoforms.

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Chou, Chung-Jung, Keith R. Shockley, Shannon B. Conners, Derrick L. Lewis, Donald A. Comfort, Michael W. W. Adams, and Robert M. Kelly. "Impact of Substrate Glycoside Linkage and Elemental Sulfur on Bioenergetics of and Hydrogen Production by the Hyperthermophilic Archaeon Pyrococcus furiosus." Applied and Environmental Microbiology 73, no. 21 (September 7, 2007): 6842–53. http://dx.doi.org/10.1128/aem.00597-07.

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ABSTRACT Glycoside linkage (cellobiose versus maltose) dramatically influenced bioenergetics to different extents and by different mechanisms in the hyperthermophilic archaeon Pyrococcus furiosus when it was grown in continuous culture at a dilution rate of 0.45 h−1 at 90ï¿½C. In the absence of S0, cellobiose-grown cells generated twice as much protein and had 50%-higher specific H2 generation rates than maltose-grown cultures. Addition of S0 to maltose-grown cultures boosted cell protein production fourfold and shifted gas production completely from H2 to H2S. In contrast, the presence of S0 in cellobiose-grown cells caused only a 1.3-fold increase in protein production and an incomplete shift from H2 to H2S production, with 2.5 times more H2 than H2S formed. Transcriptional response analysis revealed that many genes and operons known to be involved in α- or β-glucan uptake and processing were up-regulated in an S0-independent manner. Most differentially transcribed open reading frames (ORFs) responding to S0 in cellobiose-grown cells also responded to S0 in maltose-grown cells; these ORFs included ORFs encoding a membrane-bound oxidoreductase complex (MBX) and two hypothetical proteins (PF2025 and PF2026). However, additional genes (242 genes; 108 genes were up-regulated and 134 genes were down-regulated) were differentially transcribed when S0 was present in the medium of maltose-grown cells, indicating that there were different cellular responses to the two sugars. These results indicate that carbohydrate characteristics (e.g., glycoside linkage) have a major impact on S0 metabolism and hydrogen production in P. furiosus. Furthermore, such issues need to be considered in designing and implementing metabolic strategies for production of biofuel by fermentative anaerobes.

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Ajdić, Dragana, and Vi T. T. Pham. "Global Transcriptional Analysis of Streptococcus mutans Sugar Transporters Using Microarrays." Journal of Bacteriology 189, no. 14 (May 11, 2007): 5049–59. http://dx.doi.org/10.1128/jb.00338-07.

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ABSTRACT The transport of carbohydrates by Streptococcus mutans is accomplished by the phosphoenolpyruvate-phosphotransferase system (PTS) and ATP-binding cassette (ABC) transporters. To undertake a global transcriptional analysis of all S. mutans sugar transporters simultaneously, we used a whole-genome expression microarray. Global transcription profiles of S. mutans UA159 were determined for several monosaccharides (glucose, fructose, galactose, and mannose), disaccharides (sucrose, lactose, maltose, and trehalose), a β-glucoside (cellobiose), oligosaccharides (raffinose, stachyose, and maltotriose), and a sugar alcohol (mannitol). The results revealed that PTSs were responsible for transport of monosaccharides, disaccharides, β-glucosides, and sugar alcohol. Six PTSs were transcribed only if a specific sugar was present in the growth medium; thus, they were regulated at the transcriptional level. These included transporters for fructose, lactose, cellobiose, and trehalose and two transporters for mannitol. Three PTSs were repressed under all conditions tested. Interestingly, five PTSs were always highly expressed regardless of the sugar source used, presumably suggesting their availability for immediate uptake of most common dietary sugars (glucose, fructose, maltose, and sucrose). The ABC transporters were found to be specific for oligosaccharides, raffinose, stachyose, and isomaltosaccharides. Compared to the PTSs, the ABC transporters showed higher transcription under several tested conditions, suggesting that they might be transporting multiple substrates.

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Ferrer, Manuel, Olga V. Golyshina, Francisco J. Plou, Kenneth N. Timmis, and Peter N. Golyshin. "A novel α-glucosidase from the acidophilic archaeon Ferroplasma acidiphilum strain Y with high transglycosylation activity and an unusual catalytic nucleophile." Biochemical Journal 391, no. 2 (October 10, 2005): 269–76. http://dx.doi.org/10.1042/bj20050346.

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Ferroplasma acidiphilum strain Y (DSM 12658), a ferrous iron-oxidizing, acidophilic and mesophilic archaeon, was found to produce a membrane-bound α-glucosidase (αGluFa) showing no significant similarity to any of the known glycoside hydrolases classified in different families and having an unusual catalytic site consisting of a threonine and a histidine residue. The highest α-glucosidase activity was found at low pH, 2.4–3.5, and the substrate preference order was: sucrose>maltose>maltotriose ≫maltotetraose≫malto-oligosaccharides from maltopentaose to maltoheptaose⋙soluble starch (kcat/Km was 293.0, 197.0, 18.8, 0.3 and 0.02 s−1·mM−1 respectively). The enzyme was able to transfer glucosyl groups from maltose as donor, to produce exclusively maltotriose (up to 300 g/l). Chemical modification and electrospray ionization MS analysis of 5-fluoro-α-D-glucopyranosyl-enzyme derivatives, coupled with site-directed mutagenesis, strongly suggested that the putative catalytic nucleophile in this enzyme is Thr212. Iron was found to be essential for enzyme activity and integrity, and His390 was shown to be essential for iron binding. These results suggest that the metalloenzyme αGluFa is a new member of the glycosyl hydrolase family that uses a novel mechanism for sugar glycosylation and/or transglycosylation.

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Cheng, Q., and C. A. Michels. "The maltose permease encoded by the MAL61 gene of Saccharomyces cerevisiae exhibits both sequence and structural homology to other sugar transporters." Genetics 123, no. 3 (November 1, 1989): 477–84. http://dx.doi.org/10.1093/genetics/123.3.477.

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Abstract The MAL61 gene of Saccharomyces cerevisiae encodes maltose permease, a protein required for the transport of maltose across the plasma membrane. Here we report the nucleotide sequence of the cloned MAL61 gene. A single 1842 bp open reading frame is present within this region encoding the 614 residue putative MAL61 protein. Hydropathy analysis suggests that the secondary structure consists of two blocks of six transmembrane domains separated by an approximately 71 residue intracellular region. The N-terminal and C-terminal domains of 100 and 67 residues in length, respectively, also appear to be intracellular. Significant sequence and structural homology is seen between the MAL61 protein and the Saccharomyces high-affinity glucose transporter encoded by the SNF3 gene, the Kluyveromyces lactis lactose permease encoded by the LAC12 gene, the human HepG2 glucose transporter and the Escherichia coli xylose and arabinose transporters encoded by the xylE and araE genes, indicating that all are members of a family of sugar transporters and are related either functionally or evolutionarily. A mechanism for glucose-induced inactivation of maltose transport activity is discussed.

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Gehring, Kalle, Xiaochen Zhang, Jason Hall, Hiroshi Nikaido, and David E. Wemmer. "An NMR study of ligand binding by maltodextrin binding protein." Biochemistry and Cell Biology 76, no. 2-3 (May 1, 1998): 189–97. http://dx.doi.org/10.1139/o98-060.

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Proton NMR spectra of maltodextrin binding protein from Escherichia coli were used to monitor conformational changes that accompany ligand binding. Chemical shift changes associated with the binding of different maltodextrins to maltodextrin binding protein were studied using one-dimensional difference spectra. Line-shape analysis of an isolated upfield methyl resonance was used to measure the kinetics of maltose binding at several temperatures. Maltose and linear maltodextrins caused similar changes to the upfield protein spectrum with no detectable differences between alpha and beta sugar anomers. Binding of a cyclic ligand, beta-cyclodextrin, caused smaller chemical shift changes than binding of linear maltodextrins. Two maltodextrin derivatives were also studied. Both maltohexaitol and maltohexanoic acid gave one-dimensional difference spectra that were intermediate between those of linear maltodextrins and beta-cyclodextrin. The methyl resonances at -1 and -0.35 ppm were assigned to leucine 160 on the basis of homonuclear COSY and TOCSY experiments and theoretical chemical shift calculations using the X-ray crystal structure of maltodextrin binding protein.Key words: maltose binding protein, chemical shifts, chemical exchange, sugar anomer specificity.

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Guo, Gan Lin, and Lei Guo. "Optimization of DPPH Radical Scavenging Activity of Exopolysaccharides from Marine P. chrysogenum HGQ6 in Submerged Fermentation Using Response Surface Methodology." Applied Mechanics and Materials 140 (November 2011): 379–84. http://dx.doi.org/10.4028/www.scientific.net/amm.140.379.

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The objectives of this study were to investigate the effect of fermentation medium on the DPPH radical scavenging activity of exopolysaccharides from marine Penicillium chrysogenum HGQ6 by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different components of the medium. Maltose, FeSO4, and K2HPO4 were important factors significantly affecting DPPH radical scavenging activity. These selected variables were subsequently optimized using a Box-Behnken design, and response surface analysis. The optimal medium compositions were (% w/v): maltose 2.71, FeSO4 0.0016, K2HPO4 0.1, and KNO3 1.0. Under these optimal conditions, the DPPH radical scavenging rate achieved 34.0%, which agreed with the predicted values.

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Solarska, Ewa, and Magdalena Grudzińska. "The evaluation of winter wheat roots and leaf sheath diseases diagnostic methods." Acta Agrobotanica 58, no. 2 (2012): 271–76. http://dx.doi.org/10.5586/aa.2005.054.

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The maltose and mineral media for isolation of Gaeumannomyces graminis from roots were assessed. The differences in numbers of obtained isolates were found depending on the medium used and sampling date. Easier identification of pathogen was possible employing maltose medium. The fungi from genus Fusarium occurring on winter wheat leaf sheaths were identified by mycological analysis and PCR, while the fungus Pseudocercosporella herpotrichoides was detected by PCR and ELISA methods. PCR and ELISA methods enabled to detect pathogens also in periods before the disease symptoms on plants occurred.

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Horlacher, Reinhold, Karina B. Xavier, Helena Santos, Jocelyne DiRuggiero, Marina Kossmann, and Winfried Boos. "Archaeal Binding Protein-Dependent ABC Transporter: Molecular and Biochemical Analysis of the Trehalose/Maltose Transport System of the Hyperthermophilic Archaeon Thermococcus litoralis." Journal of Bacteriology 180, no. 3 (February 1, 1998): 680–89. http://dx.doi.org/10.1128/jb.180.3.680-689.1998.

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ABSTRACT We report the cloning and sequencing of a gene cluster encoding a maltose/trehalose transport system of the hyperthermophilic archaeonThermococcus litoralis that is homologous to themalEFG cluster encoding the Escherichia colimaltose transport system. The deduced amino acid sequence of themalE product, the trehalose/maltose-binding protein (TMBP), shows at its N terminus a signal sequence typical for bacterial secreted proteins containing a glyceride lipid modification at the N-terminal cysteine. The T. litoralis malE gene was expressed in E. coli under control of an inducible promoter with and without its natural signal sequence. In addition, in one construct the endogenous signal sequence was replaced by the E. coli MalE signal sequence. The secreted, soluble recombinant protein was analyzed for its binding activity towards trehalose and maltose. The protein bound both sugars at 85°C with aKd of 0.16 μM. Antibodies raised against the recombinant soluble TMBP recognized the detergent-soluble TMBP isolated from T. litoralis membranes as well as the products from all other DNA constructs expressed in E. coli. Transmembrane segments 1 and 2 as well as the N-terminal portion of the large periplasmic loop of the E. coli MalF protein are missing in the T. litoralis MalF. MalG is homologous throughout the entire sequence, including the six transmembrane segments. The conserved EAA loop is present in both proteins. The strong homology found between the components of this archaeal transport system and the bacterial systems is evidence for the evolutionary conservation of the binding protein-dependent ABC transport systems in these two phylogenetic branches.

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Dattelbaum, J. D. "Analysis of allosteric signal transduction mechanisms in an engineered fluorescent maltose biosensor." Protein Science 14, no. 2 (February 1, 2005): 284–91. http://dx.doi.org/10.1110/ps.041146005.

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Basu, Anindya, Sarma Mutturi, and Siddalingaiya Gurudutt Prapulla. "Modeling of enzymatic production of isomaltooligosaccharides: a mechanistic approach." Catalysis Science & Technology 5, no. 5 (2015): 2945–58. http://dx.doi.org/10.1039/c5cy00003c.

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In the current investigation the production of isomaltooligosaccharides (IMO) by transglucosylation of maltose using α-glucosidase was modeled by a mechanistic approach. Parameters are estimated by a genetic algorithm followed by sensitivity analysis and experimental validation.

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Journal articles on the topic 'Maltose Analysis'

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