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Cas9-assisted genome editing was used to construct an engineered glucose-phosphorylation-negative S. cerevisiae strain, expressing the Lactobacillus plantaruml-arabinose pathway and the Penicillium chrysogenum transporter PcAraT. This strain, which showed a growth rate of 0.26 h-1 on l-arabinose in aerobic batch cultures, was subsequently evolved for anaerobic growth on l-arabinose in the presence of d-glucose and d-xylose. In four strains isolated from two independent evolution experiments the galactose-transporter gene GAL2 had been duplicated, with all alleles encoding Gal2N376T or Gal2N376I substitutions. In one strain, a single GAL2 allele additionally encoded a Gal2T89I substitution, which was subsequently also detected in the independently evolved strain IMS0010. In 14C-sugar-transport assays, Gal2N376S, Gal2N376T and Gal2N376I substitutions showed a much lower glucose sensitivity of l-arabinose transport and a much higher Km for d-glucose transport than wild-type Gal2. Introduction of the Gal2N376I substitution in a non-evolved strain enabled growth on l-arabinose in the presence of d-glucose. Gal2N376T, T89I and Gal2T89I variants showed a lower Km for l-arabinose and a higher Km for d-glucose than wild-type Gal2, while reverting Gal2N376T, T89I to Gal2N376 in an evolved strain negatively affected anaerobic growth on arabinose. This study indicates that optimal conversion of mixed-sugar feedstocks may require complex 'transporter landscapes', consisting of sugar transporters with complementary kinetic and regulatory properties.
This article was published in the following journal.
Name: FEMS yeast research
d-Glucose, d-xylose and l-arabinose are major sugars in lignocellulosic hydrolysates. This study explores fermentation of glucose-xylose-arabinose mixtures by a consortium of three 'specialist' Saccha...
Catabolite repression refers to the process where the metabolism of one sugar represses the genes involved in metabolizing another sugar. While glucose provides the canonical example, many other sugar...
Saccharomyces cerevisiae is a Crabtree-positive eukaryal model organism. It is believed that the Crabtree effect has evolved as a competition mechanism by allowing for rapid growth and production of e...
To efficiently ferment intermediate cellodextrins released during cellulose hydrolysis, Saccharomyces cerevisiae has been engineered by introduction of a heterologous cellodextrin utilizing pathway co...
Post-transcriptional regulation is an important mechanism for modulating gene expression and is performed by numerous mRNA-binding proteins. To understand the mechanisms underlying post-transcriptiona...
The purpose of this study is to investigate the effect of L-arabinose in a sugar-rich meal on intestinal sucrase activity in healthy volunteers by measuring postprandial blood glucose and ...
This study was designed to examine changes in capillary blood glucose and venous insulin levels after a 70 gram oral sucrose challenge with and without simultaneous consumption of a dietar...
We are proposing a clinical investigation of the pathogenesis of insulin resistance (IR) in skeletal muscle and adipose tissue (AT), focusing specifically on the contributions of glucose d...
This study aims to investigate the effect of supplement containing L-arabinose and indigestible dextrin on body mass index, body fat mass, abdominal circumference, visceral fat mass, and s...
This study aims to investigate the effect of supplement containing L-arabinose and indigestible dextrin on dietary glycemic index.
Self evaluation of whole blood glucose levels outside the clinical laboratory. A digital or battery-operated reflectance meter may be used. It has wide application in controlling unstable insulin-dependent diabetes.
The interdisciplinary science that studies evolutionary biology, including the origin and evolution of the major elements required for life, their processing in the interstellar medium and in protostellar systems. This field also includes the study of chemical evolution and the subsequent interactions between evolving biota and planetary evolution as well as the field of biology that deals with the study of extraterrestrial life.
A plasma protein which is the precursor of kallikrein. Plasma that is deficient in prekallikrein has been found to be abnormal in thromboplastin formation, kinin generation, evolution of a permeability globulin, and plasmin formation. The absence of prekallikrein in plasma leads to Fletcher factor deficiency, a congenital disease.
Maintenance of a constant blood glucose level by perfusion or infusion with glucose or insulin. It is used for the study of metabolic rates (e.g., in glucose, lipid, amino acid metabolism) at constant glucose concentration.
Evolution at the molecular level of DNA sequences and proteins. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Bioinformatics is the application of computer software and hardware to the management of biological data to create useful information. Computers are used to gather, store, analyze and integrate biological and genetic information which can then be applied...
Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...
Immunoassay - ELISA
Immunoassays are quick and accurate tests to detect specific molecules. Immunoassays rely on an antibody to bind to the specific structure of a molecule. Antibodies are proteins generated by animals in response to the invasion of a foreign molecule (anti...