<Emphasis Type="Italic">PGM2</Emphasis> overexpression improves anaerobic galactose fermentation in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Background  

In Saccharomyces cerevisiae galactose is initially metabolized through the Leloir pathway after which glucose 6-phosphate enters glycolysis. Galactose is controlled both by glucose repression and by galactose induction. The gene PGM2 encodes the last enzyme of the Leloir pathway, phosphoglucomutase 2 (Pgm2p), which catalyses the reversible conversion of glucose 1-phosphate to glucose 6-phosphate. Overexpression of PGM2 has previously been shown to enhance aerobic growth of S. cerevisiae in galactose medium.     

Glycolysis and the regulation of glucose transport in <Emphasis Type="Italic">Lactococcus lactis</Emphasis> spp. <Emphasis Type="Italic">lactis</Emphasis> in batch and fed-batch culture

Background  

Despite the fact that many reports deal with glycolysis in Lactococcus lactis, there is not much information on the regulation of uptake of glucose itself. The aim of the present work was to investigate the effect of the glucose level on its specific uptake rate.     

Expression of a novel gene, <Emphasis Type="Italic">gluP</Emphasis>, is essential for normal <Emphasis Type="Italic">Bacillus subtilis</Emphasis> cell division and contributes to glucose export

Background  

The Bacillus subtilis glucokinase operon was predicted to be comprised of the genes, yqgP (now named gluP), yqgQ, and glcK. We have previously established a role for glcK in glucose metabolism. In the absence of enzymes that phosphorylate glucose, such as GlcK and/or enzyme II^Glc, accumulated cytoplasmic glucose can be transported out of the cell. Genes within the glucokinase operon were not previously known to play a role in glucose transport. Here we describe the expression of gluP and its function in glucose transport.     

<Emphasis Type="Italic">Bacillus subtilis</Emphasis> GlcK activity requires cysteines within a motif that discriminates microbial glucokinases into two lineages

Background  

Bacillus subtilis glucokinase (GlcK) (GenBank NP_390365) is an ATP-dependent kinase that phosphorylates glucose to glucose 6-phosphate. The GlcK protein has very low sequence identity (13.7%) to the Escherichia coli glucokinase (Glk) (GenBank P46880) and some other glucokinases (EC 2.7.1.2), yet glucose is merely its substrate. Our lab has previously isolated and characterized the glcK gene.     

Reconstruction and logical modeling of glucose repression signaling pathways in Saccharomyces cerevisiae

Background  

In the yeast Saccharomyces cerevisiae, the presence of high levels of glucose leads to an array of down-regulatory effects known as glucose repression. This process is complex due to the presence of feedback loops and crosstalk between different pathways, complicating the use of intuitive approaches to analyze the system.     

Butyrate ingestion improves hepatic glycogen storage in the re-fed rat

Background  

Butyrate naturally produced by intestinal fiber fermentation is the main nutrient for colonocytes, but the metabolic effect of the fraction reaching the liver is not totally known. After glycogen hepatic depletion in the 48-hour fasting rat, we monitored the effect of (butyrate 1.90 mg + glucose 14.0 mg)/g body weight versus isocaloric (glucose 18.2 mg/g) or isoglucidic (glucose 14.0 mg/g) control force-feeding on in vivo changes in hepatic glycogen and ATP contents evaluated ex vivo by NMR in the isolated and perfused liver.     

Role of casein kinase 1 in the glucose sensor-mediated signaling pathway in yeast

Background  

In yeast, glucose-dependent degradation of the Mth1 protein, a corepressor of the glucose transporter gene (HXT) repressor Rgt1, is a crucial event enabling expression of several HXT. This event occurs through a signaling pathway that involves the Rgt2 and Snf3 glucose sensors and yeast casein kinase 1 and 2 (Yck1/2). In this study, we examined whether the glucose sensors directly couple with Yck1/2 to convert glucose binding into an intracellular signal that leads to the degradation of Mth1.     

Glucose-free fructose production from Jerusalem artichoke using a recombinant inulinase-secreting <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> strain

Purpose of work  

Using inulin (polyfructose) obtained from Jerusalen artichokes, we have produced fructose free of residual glucose using a recombinant inulinase-secreting strain of Saccharomyces cerevisiae in a one-step fermentation of Jerusalem artichoke tubers.     

The impact of ColRS two-component system and TtgABC efflux pump on phenol tolerance of <Emphasis Type="Italic">Pseudomonas putida</Emphasis> becomes evident only in growing bacteria

Background  

We have recently found that Pseudomonas putida deficient in ColRS two-component system is sensitive to phenol and displays a serious defect on solid glucose medium where subpopulation of bacteria lyses. The latter phenotype is significantly enhanced by the presence of phenol in growth medium. Here, we focused on identification of factors affecting phenol tolerance of the colR-deficient P. putida.     

Effect of <Emphasis Type="Italic">HXT</Emphasis> 1 and <Emphasis Type="Italic">HXT</Emphasis> 7 hexose transporter overexpression on wild-type and lactic acid producing <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> cells

Background  

Since about three decades, Saccharomyces cerevisiae can be engineered to efficiently produce proteins and metabolites. Even recognizing that in baker's yeast one determining step for the glucose consumption rate is the sugar uptake, this fact has never been conceived to improve the metabolite(s) productivity.     

Coutilization of glucose and glycerol enhances the production of aromatic compounds in an Escherichia coli strain lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system

Background  

Escherichia coli strains lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS) are capable of coutilizing glucose and other carbon sources due to the absence of catabolite repression by glucose. In these strains, the lack of this important regulatory and transport system allows the coexistence of glycolytic and gluconeogenic pathways. Strains lacking PTS have been constructed with the goal of canalizing part of the phosphoenolpyruvate (PEP) not consumed in glucose transport to the aromatic pathway. The deletion of the ptsHIcrr operon inactivates PTS causing poor growth on this sugar; nonetheless, fast growing mutants on glucose have been isolated (PB12 strain). However, there are no reported studies concerning the growth potential of a PTS^- strain in mixtures of different carbon sources to enhance the production of aromatics compounds.     

A novel hydroxyfuroic acid compound as an insulin receptor activator - structure and activity relationship of a prenylindole moiety to insulin receptor activation

Background  

Diabetes Mellitus is a chronic disease and many patients of which require frequent subcutaneous insulin injection to maintain proper blood glucose levels. Due to the inconvenience of insulin administration, an orally active insulin replacement has long been a prime target for many pharmaceutical companies. Demethylasterriquinone (DMAQ) B1, extracted from tropical fungus, Pseudomassaria sp., has been reported to be an orally effective agent at lowering circulating glucose levels in diabetic (db/db) mice; however, the cytotoxicity associated with the quinone moiety has not been addressed thus far.     

Improved vanillin production in baker's yeast through <Emphasis Type="Italic">in silico</Emphasis> design

Background  

Vanillin is one of the most widely used flavouring agents, originally obtained from cured seed pods of the vanilla orchid Vanilla planifolia. Currently vanillin is mostly produced via chemical synthesis. A de novo synthetic pathway for heterologous vanillin production from glucose has recently been implemented in baker's yeast, Saccharamyces cerevisiae. In this study we aimed at engineering this vanillin cell factory towards improved productivity and thereby at developing an attractive alternative to chemical synthesis.