-
Communications Biology Oct 2023The Gram-negative bacteria Salmonella enterica and Escherichia coli are important model organisms, powerful prokaryotic expression platforms for biotechnological...
The Gram-negative bacteria Salmonella enterica and Escherichia coli are important model organisms, powerful prokaryotic expression platforms for biotechnological applications, and pathogenic strains constitute major public health threats. To facilitate new approaches for research and biotechnological applications, we here develop a set of arabinose-inducible artificial transcription factors (ATFs) using CRISPR/dCas9 and Arabidopsis-derived DNA-binding proteins to control gene expression in E. coli and Salmonella over a wide inducer concentration range. The transcriptional output of the different ATFs, in particular when expressed in Salmonella rewired for arabinose catabolism, varies over a wide spectrum (up to 35-fold gene activation). As a proof-of-concept, we use the developed ATFs to engineer a Salmonella two-input biosensor strain, SALSOR 0.2 (SALmonella biosenSOR 0.2), which detects and quantifies alkaloid drugs through a measurable fluorescent output. Moreover, we use plant-derived ATFs to regulate β-carotene biosynthesis in E. coli, resulting in ~2.1-fold higher β-carotene production compared to expression of the biosynthesis pathway using a strong constitutive promoter.
Topics: Transcription Factors; Escherichia coli; Arabinose; Enterobacteriaceae; beta Carotene
PubMed: 37789111
DOI: 10.1038/s42003-023-05363-3 -
Plant & Cell Physiology Dec 2021Growth, development, structure as well as dynamic adaptations and remodeling processes in plants are largely controlled by properties of their cell walls. These... (Review)
Review
Growth, development, structure as well as dynamic adaptations and remodeling processes in plants are largely controlled by properties of their cell walls. These intricate wall structures are mostly made up of different sugars connected through specific glycosidic linkages but also contain many glycosylated proteins. A key plant sugar that is present throughout the plantae, even before the divergence of the land plant lineage, but is not found in animals, is l-arabinose (l-Ara). Here, we summarize and discuss the processes and proteins involved in l-Ara de novo synthesis, l-Ara interconversion, and the assembly and recycling of l-Ara-containing cell wall polymers and proteins. We also discuss the biological function of l-Ara in a context-focused manner, mainly addressing cell wall-related functions that are conferred by the basic physical properties of arabinose-containing polymers/compounds. In this article we explore these processes with the goal of directing future research efforts to the many exciting yet unanswered questions in this research area.
Topics: Arabinose; Cell Wall; Plants
PubMed: 34129041
DOI: 10.1093/pcp/pcab087 -
Journal of Agricultural and Food... Aug 2023During the production of ethanol from lignocellulose-derived sugars, recombinant yeasts tend to utilize xylose and arabinose after glucose exhaustion. So far, many...
During the production of ethanol from lignocellulose-derived sugars, recombinant yeasts tend to utilize xylose and arabinose after glucose exhaustion. So far, many glucose-insensitive pentose transporters have been reported to counteract this phenomenon, but few studies have described intracellular factors. In this study, the combination of adaptive evolution, comparative genomics, and genetic complementation revealed that the hexokinase-deficient () arabinose-fermenting requires the arabinose transporter variant Gal2-N376T and the mutations of guanine nucleotide exchange factor Cdc25 to overcome glucose restriction during arabinose assimilation. The results showed that the recombinant yeasts could lower the metabolic/physiological threshold of cell proliferation by downregulating the intracellular cAMP levels, resulting in smaller cells and increased arabinose assimilation under glucose restriction. In the medium containing 80 g/L glucose and 20 g/L arabinose, the evolved strain restoring the hexokinase activity completed fermentation at 22 h, compared to 24 h for the parental strain. Overall, the experimental results provide new insights into glucose repression of biorefinery yeasts.
Topics: Saccharomyces cerevisiae; Arabinose; Glucose; Hexokinase; Signal Transduction
PubMed: 37592391
DOI: 10.1021/acs.jafc.3c04386 -
International Journal of Biological... May 2022One galactose- and arabinose-rich polysaccharide isolated from Sambucus adnata was named SPS-1, which had an average molecular weight 138.52 kDa, and was composed of...
One galactose- and arabinose-rich polysaccharide isolated from Sambucus adnata was named SPS-1, which had an average molecular weight 138.52 kDa, and was composed of L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-galactose, and L-arabinose in a molar ratio of 0.6:0.4:0.1:4.9:4.0. The primary structure of SPS-1 was further analyzed through methylation and NMR spectroscopy. The results showed that SPS-1 had the structural characteristics of AG-II pectin. The immunoactivity test showed that SPS-1 activated the phosphorylation of MAPKs-related proteins and further elevated the expression levels of related nuclear transcription factors (IκBα and NF-κB p65) in the cells through the TLR2 and MyD88/TRAF6-dependent pathway, thereby significantly enhancing the phagocytosis of macrophages and stimulating the secretion of NO, IL-1β, IL-6, and TNF-α, which activated the RAW264.7 cells. Therefore, SPS-1, acting as an immunomodulator, is a potential drug for immunological diseases.
Topics: Animals; Arabinose; Galactose; Mice; Polysaccharides; RAW 264.7 Cells; Sambucus
PubMed: 35346678
DOI: 10.1016/j.ijbiomac.2022.03.132 -
Frontiers in Cellular and Infection... 2021L-arabinose inducible promoters are commonly used in gene expression analysis. However, nutrient source and availability also play a role in biofilm formation;...
L-arabinose inducible promoters are commonly used in gene expression analysis. However, nutrient source and availability also play a role in biofilm formation; therefore, L-arabinose metabolism could impact biofilm development. In this study we examined the impact of L-arabinose on serovar Typhimurium (. Typhimurium) biofilm formation. Using mutants impaired for the transport and metabolism of L-arabinose, we showed that L-arabinose metabolism negatively impacts Typhimurium biofilm formation . When L-arabinose metabolism is abrogated, biofilm formation returned to baseline levels. However, without the ability to import extracellular L-arabinose, biofilm formation significantly increased. Using RNA-Seq we identified several gene families involved in these different phenotypes including curli expression, amino acid synthesis, and L-arabinose metabolism. Several individual candidate genes were tested for their involvement in the L-arabinose-mediated biofilm phenotypes, but most played no significant role. Interestingly, in the presence of L-arabinose the diguanylate cyclase gene A was downregulated in wild type . Typhimurium. Meanwhile , encoding an adenylate cyclase, was downregulated in an L-arabinose transport mutant. Using an IPTG-inducible plasmid to deplete c-di-GMP expression, we were able to abolish the increased biofilm phenotype seen in the transport mutant. However, the mechanism by which the L-arabinose import mutant forms significantly larger biofilms remains to be determined. Regardless, these data suggest that L-arabinose metabolism influences intracellular c-di-GMP levels and therefore biofilm formation. These findings are important when considering the use of an L-arabinose inducible promoter in biofilm conditions.
Topics: Arabinose; Bacterial Proteins; Biofilms; Cyclic GMP; Gene Expression Regulation, Bacterial; Plasmids; Salmonella typhimurium
PubMed: 34368016
DOI: 10.3389/fcimb.2021.698146 -
The Journal of Physical Chemistry. A Jul 2021Arabinose and ribose are two common pentoses that exist in both furanose and pyranose forms in plant and bacteria oligosaccharides. In this study, each pentose isomer,...
Arabinose and ribose are two common pentoses that exist in both furanose and pyranose forms in plant and bacteria oligosaccharides. In this study, each pentose isomer, namely α-furanose, β-furanose, α-pyranose, and β-pyranose, was first separated through high-performance liquid chromatography followed by an investigation of collision-induced dissociation in an ion trap mass spectrometer. The major dissociation channels, dehydration and cross-ring dissociation, were analyzed by using high-level quantum chemistry calculations and transition state theory. The branching ratio of major dissociation channels was governed by two geometrical features: one being the cis or trans configuration of O1 and O2 atoms determining dehydration preferability and the other being the number of hydroxyl groups on the same side of the ring as the O1 atom determining the preferability of cross-ring dissociation. The relative branching ratios of the major channels were used to identify anomericity and the linkages of arabinose and ribose. Arabinose in the β-configuration and ribose in the α-configuration are predicted to have larger relative dehydration branching ratios than arabinose in the α-configuration and ribose in the β-configuration, respectively. Arabinose and ribose at the reducing end of oligosaccharides with 1 → 2 (pyranose and furanose), 1 → 3 (pyranose and furanose), 1 → 4 (pyranose only), and 1 → 5 (furanose only) linkages are predicted to undergo X, X, A, and A/A cross-ring dissociation, respectively. Application of the dissociation mechanism to the disaccharide linkage determination is demonstrated.
PubMed: 34256570
DOI: 10.1021/acs.jpca.1c03854 -
International Journal of Biological... Jan 2021L-Fuculose and D-ribulose are kinds of rare sugars used in food, agriculture, and medicine industries. These are pentoses and categorized into the two main groups, aldo... (Review)
Review
L-Fuculose and D-ribulose are kinds of rare sugars used in food, agriculture, and medicine industries. These are pentoses and categorized into the two main groups, aldo pentoses and ketopentoses. There are 8 aldo- and 4 ketopentoses and only fewer are natural, while others are rare sugars found in a very small amount in nature. These sugars have great commercial applications, especially in many kinds of drugs in the medicine industry. The synthesis of these sugars is very expensive, difficult by chemical methods due to its absence in nature, and could not meet industry demands. The pentose izumoring strategy offers a complete enzymatic tactic to link all kinds of pentoses using different enzymes. The enzymatic production of L-fuculose and D-ribulose through L-fucose isomerase (L-FI) and D-arabinose isomerase (D-AI) is the inexpensive and uncomplicated method up till now. Both enzymes have similar kinds of isomerizing mechanisms and each enzyme can catalyze both L-fucose and D-arabinose. In this review article, the enzymatic process of biochemically characterized L-FI & D-AI, their application to produce L-fuculose and D-ribulose and its uses in food, agriculture, and medicine industries are reviewed.
Topics: Agriculture; Aldose-Ketose Isomerases; Food Industry; Hexoses; Pentoses; Substrate Specificity
PubMed: 33296692
DOI: 10.1016/j.ijbiomac.2020.12.021 -
Applied Microbiology and Biotechnology Apr 2020L-Ribose is a non-naturally occurring pentose that recently has become known for its potential application in the pharmaceutical industry, as it is an ideal starting... (Review)
Review
L-Ribose is a non-naturally occurring pentose that recently has become known for its potential application in the pharmaceutical industry, as it is an ideal starting material for use in synthesizing L-nucleosides analogues, an important class of antiviral drugs. In the past few decades, the synthesis of L-ribose has been mainly undertaken through the chemical route. However, chemical synthesis of L-ribose is difficult to achieve on an industrial scale. Therefore, the biotechnological production of L-ribose has gained considerable attention, as it exhibits many merits over the chemical approaches. The present review focuses on various biotechnological strategies for the production of L-ribose through microbial biotransformation and enzymatic catalysis, and in particular on an analysis and comparison of the synthetic methods and different enzymes. The physiological functions and applications of L-ribose are also elucidated. In addition, different sugar isomerases involved in the production of L-ribose from a number of sources are discussed in detail with regard to their biochemical properties. Furthermore, analysis of the separation issues of L-ribose from the reaction solution and different purification methods is presented.Key points • l -Arabinose, l -ribulose and ribitol can be used to produce l -ribose by enzymes. • Five enzymes are systematically introduced for production of l -ribose. • Microbial transformation and enzymatic methods are promising for yielding l -ribose.
Topics: Arabinose; Bacteria; Biotechnology; Biotransformation; Enzymes, Immobilized; Isomerases; Ribose
PubMed: 32088757
DOI: 10.1007/s00253-020-10471-9 -
Nutrition & Metabolism Apr 2022Hypercholesterolemia is closely associated with an increased risk of cardiovascular diseases. L-Arabinose exhibited hypocholesterolemia properties, but underlying...
BACKGROUND
Hypercholesterolemia is closely associated with an increased risk of cardiovascular diseases. L-Arabinose exhibited hypocholesterolemia properties, but underlying mechanisms have not been sufficiently investigated. This study aimed to elucidate the mechanisms of L-arabinose on hypocholesterolemia involving the enterohepatic circulation of bile acids.
METHODS
Thirty six-week-old male mice were randomly divided into three groups: the control group and the high-fat-high-sucrose diet (HFHSD)-fed group were gavaged with distilled water, and the L-arabinose-treated group were fed HFHSD and received 400 mg/kg/day L-arabinose for 12 weeks. Serum and liver biochemical parameters, serum and fecal bile acid, cholesterol and bile acid metabolism-related gene and protein expressions in the liver and small intestine were analyzed.
RESULTS
L-Arabinose supplementation significantly reduced body weight gain, lowered circulating low-density lipoprotein cholesterol (LDL-C) while increasing high-density lipoprotein cholesterol (HDL-C) levels, and efficiently alleviated hepatic inflammation and lipid accumulations in HFHSD-fed mice. L-Arabinose inhibited cholesterol synthesis via downregulation of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). Additionally, L-arabinose might facilitate reverse cholesterol transport, evidenced by the increased mRNA expressions of low-density lipoprotein receptor (LDL-R) and scavenger receptor class B type 1 (SR-B1). Furthermore, L-arabinose modulated ileal reabsorption of bile acids mainly through downregulation of ileal bile acid-binding protein (I-BABP) and apical sodium-dependent bile acid transporter (ASBT), resulting in the promotion of hepatic synthesis of bile acids via upregulation of cholesterol-7α-hydroxylase (CYP7A1).
CONCLUSIONS
L-Arabinose supplementation exhibits hypocholesterolemic effects in HFHSD-fed mice primarily due to regulation of bile acid metabolism-related pathways.
PubMed: 35428331
DOI: 10.1186/s12986-022-00662-8 -
Journal of Food Science and Technology Mar 2021The furan levels in commercial coffee product samples (17 instant coffees, 12 mixed coffee, 8 canned coffee) were 49-2155, 10-201 and 15-209 ng/g, respectively. Since...
The furan levels in commercial coffee product samples (17 instant coffees, 12 mixed coffee, 8 canned coffee) were 49-2155, 10-201 and 15-209 ng/g, respectively. Since thermal degradation/rearrangement of carbohydrates is the main source of furan, the concentrations of furan and monosaccharides (mannose, rhamnose, glucose, galactose and arabinose) were analysed in 26 green and roasted coffee bean () varieties. In coffee beans, furan levels ranged from 4.71 (Bourbon Cerrado, Brazil) to 8.63 mg/kg (San Vicente, Honduras). Galactose was the main monosaccharide in green beans, followed by arabinose, glucose, mannose and rhamnose, on average. Roasting decreased the glucose content by about 81%, and arabinose decreased about 27% in all coffee beans. Glucose decreased the greatest after roasting and is thereby considered the major contributor to the formation of furan.
PubMed: 33678869
DOI: 10.1007/s13197-020-04600-5