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Gonzalo N Bidart, Jesús Rodríguez-Díaz, Gaspar Pérez-Martínez, María J Yebra
The lactose operon (lacTEGF) from Lactobacillus casei strain BL23 has been previously studied. The lacT gene codes for a transcriptional antiterminator, lacE and lacF for the lactose-specific phosphoenolpyruvate: phosphotransferase system (PTSLac ) EIICB and EIIA domains, respectively, and lacG for the phospho-β-galactosidase. In this work, we have shown that L. casei is able to metabolize N-acetyllactosamine (LacNAc), a disaccharide present at human milk and intestinal mucosa. The mutant strains BL153 (lacE) and BL155 (lacF) were defective in LacNAc utilization, indicating that the EIICB and EIIA of the PTSLac are involved in the uptake of LacNAc in addition to lactose...
May 8, 2018: Scientific Reports
Carine Vergne-Vaxelaire, Aline Mariage, Jean-Louis Petit, Aurélie Fossey-Jouenne, Christine Guérard-Hélaine, Ekaterina Darii, Adrien Debard, Stessy Nepert, Virginie Pellouin, Marielle Lemaire, Anne Zaparucha, Marcel Salanoubat, Véronique de Berardinis
Most of the "repressor, open reading frame, kinase" (ROK) proteins already characterized so far, and exhibiting a kinase activity, take restrictedly D-glucose as substrate. By exploring the sequenced bacterial diversity, 61 ATP-dependent kinases belonging to the ROK family have been identified and experimentally assayed for the phosphorylation of hexoses. These kinases were mainly found to be thermotolerant and highly active toward D-mannose and D-fructose with notable activities toward D-tagatose...
May 4, 2018: Applied Microbiology and Biotechnology
Tien-Kieu Nguyen, Moon-Gi Hong, Pahn-Shick Chang, Byung-Hoo Lee, Sang-Ho Yoo
d-Tagatose has gained substantial interest due to its potential functionalities as a sucrose substitute. In this study, the gene araA, encoding l-arabinose isomerase (l-AI) from Clostridium hylemonae (DSM 15053), was cloned and expressed in Escherichia coli BL21 (DE3). This gene consists of 1,506 nucleotides and encodes a protein of 501 amino acid residues with a calculated molecular mass of 56,554 Da. Since l-AI was expressed as an intracellular inclusion body, this enzyme was solubilized with guanidine hydrochloride, refolded, and activated with a descending concentration gradient of urea...
2018: PloS One
Benoit Jacques, Mathieu Coinçon, Jurgen Sygusch
Crystal structures of two bacterial metal (Zn) dependent D-fructose 1,6-bisphosphate (FBP) aldolases in complex with substrate, analogues, and triose-P reaction products were determined to 1.5-2.0 Å resolution. The ligand complexes cryotrapped in native or mutant H. pylori aldolase crystals enabled a novel mechanistic description of FBP C3 -C4 bond cleavage. The reaction mechanism uses active site remodelling during the catalytic cycle implicating relocation of the Zn cofactor that is mediated by conformational changes of active site loops...
March 28, 2018: Journal of Biological Chemistry
Marion Guerrero-Wyss, Samuel Durán Agüero, Lisse Angarita Dávila
The objective of the current research was to review and update evidence on the dietary effect of the consumption of tagatose in type 2 diabetes, as well as to elucidate the current approach that exists on its production and biotechnological utility in functional food for diabetics. Articles published before July 1, 2017, were included in the databases PubMed, EBSCO, Google Scholar, and Scielo, including the terms "Tagatose", "Sweeteners", "Diabetes Mellitus type 2", "Sweeteners", "D-Tag"...
2018: BioMed Research International
Jian Ji, Pei Zhu, Ivana Blaženović, Fangchao Cui, Morteza Gholami, Jiadi Sun, Jean Habimana, Yinzhi Zhang, Xiulan Sun
Urine metabolic profiling of mice was conducted utilizing gas chromatography-mass spectrometry (GC-MS) to investigate the combinatory effect of mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) on the metabolism of the mice. Experiments were conducted by means of five-week-old mice which were individually exposed to 2 mg/kg DON, 20 mg/kg ZEN and the mixture of DON and ZEN (2 mg/kg and 20 mg/kg, respectively). The intragastric administration was applied for three weeks and urine samples were collected for metabolic analysis...
February 28, 2018: Scientific Reports
Toshiharu Yakushi, Yuka Terada, Seishiro Ozaki, Naoya Kataoka, Yoshihiko Akakabe, Osao Adachi, Minenosuke Matsutani, Kazunobu Matsushita
Membrane-bound, pyrroloquinoline quinone (PQQ)-dependent glycerol dehydrogenase (GLDH, or polyol dehydrogenase) of Gluconobacter sp. oxidizes various secondary alcohols to produce the corresponding ketones, such as oxidation of D-sorbitol to L-sorbose in vitamin C production. Substrate specificity of GLDH is considered limited to secondary alcohols in the D-erythro configuration at the next to the last carbon. Here, we suggest that L-ribose, D- and L-lyxoses, and L-tagatose are also substrates of GLDH, but these sugars do not meet the substrate specificity rule of GLDH...
April 2018: Applied Microbiology and Biotechnology
Y Shi, R Li, D J White, A R Biesbrock
A genome-wide transcriptional analysis was performed to elucidate the bacterial cellular response of Streptococcus mutans and Actinomyces viscosus to NaF and SnF2 . The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of SnF2 were predetermined before microarray study. Gene expression profiling microarray experiments were carried out in the absence (control) and presence (experimental) of 10 ppm and 100 ppm Sn2+ (in the form of SnF2 ) and fluoride controls for 10-min exposures (4 biological replicates/treatment)...
February 2018: Advances in Dental Research
Marylane de Sousa, Ricardo M Manzo, José L García, Enrique J Mammarella, Luciana R B Gonçalves, Benevides C Pessela
l-Arabinose isomerase (EC (l-AI) from Enterococcus faecium DBFIQ E36 was overproduced in Escherichia coli by designing a codon-optimized synthetic araA gene. Using this optimized gene, two N- and C-terminal His-tagged-l-AI proteins were produced. The cloning of the two chimeric genes into regulated expression vectors resulted in the production of high amounts of recombinant N -His-l-AI and C -His-l-AI in soluble and active forms. Both His-tagged enzymes were purified in a single step through metal-affinity chromatography and showed different kinetic and structural characteristics...
December 6, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Feng Lin, Yi Ou, Chuan-Zhong Huang, Sheng-Zhe Lin, Yun-Bin Ye
The aim of this study was to identify metabolite biomarkers associated with acute rejection after heart transplantation in rats using a LC-MS-based metabolomics approach. A model of heterotopic cardiac xenotransplantation was established in rats, with Wistar rats as donors and SD rats as recipients. Blood and cardiac samples were collected from blank control rats (Group A), rats 5 (Group B) and 7 days (Group C) after heart transplantation, and pretreated rats 5 (Group D) and 7 days (Group E) post-transplantation for pathological and metabolomics analyses...
November 13, 2017: Scientific Reports
Arshag D Mooradian, Meridith Smith, Masaaki Tokuda
The rapid increase in the prevalence of obesity worldwide has been partially attributed to the overconsumption of added sugars. Recent guidelines call for limiting the consumption of simple sugars to less than 10% of daily caloric consumption. High intensity sweeteners are regulated as food additives and include aspartame, acesulfame-k, neotame, saccharin, sucralose, cyclamate and alitame. Steviol glycosides and Luo Han Guo fruit extracts are high intensity sweeteners that are designated as generally recognized as safe (GRAS)...
April 2017: Clinical Nutrition ESPEN
Zhengliang Qi, Zhangliang Zhu, Jian-Wen Wang, Songtao Li, Qianqian Guo, Panpan Xu, Fuping Lu, Hui-Min Qin
BACKGROUND: D-Tagatose 3-epimerase epimerizes D-fructose to yield D-psicose, which is a rare sugar that exists in small quantities in nature and is difficult to synthesize chemically. We aim to explore potential industrial biocatalysts for commercial-scale manufacture of this rare sugar. A D-tagatose 3-epimerase from Rhodobacter sphaeroides (RsDTE) has recently been identified as a D-tagatose 3-epimerase that can epimerize D-fructose to yield D-psicose with a high conversion rate. RESULTS: The purified RsDTE by Ni-affinity chromatography, ionic exchange chromatography and gel filtration forms a tetramer in solution...
November 9, 2017: Microbial Cell Factories
Khaleque Hasibul, Haruyuki Nakayama-Imaohji, Masahito Hashimoto, Hisashi Yamasaki, Takaaki Ogawa, Junpei Waki, Ayano Tada, Saori Yoneda, Masaaki Tokuda, Minoru Miyake, Tomomi Kuwahara
Dental caries is an important global health concern and Streptococcus mutans has been established as a major cariogenic bacterial species. Reports indicate that a rare sugar, D‑tagatose, is not easily catabolized by pathogenic bacteria. In the present study, the inhibitory effects of D‑tagatose on the growth and biofilm formation of S. mutans GS‑5 were examined. Monitoring S. mutans growth over a 24 h period revealed that D‑tagatose prolonged the lag phase without interfering with the final cell yield...
January 2018: Molecular Medicine Reports
Jun-Yeong Lee, Geon Goo Han, Ho-Bin Lee, Sang-Mok Lee, Sang-Kee Kang, Gwi-Deuk Jin, Jongbin Park, Byung Jo Chae, Yo Han Choi, Eun Bae Kim, Yun-Jaie Choi
After the introduction of a ban on the use of antibiotic growth promoters (AGPs) for livestock, the feeding environment, including the composition of animal intestinal microbiota, has changed rapidly. We hypothesized that the microbial genomes have also been affected by this legal prohibition, and investigated an important member of the swine gut microbiota, Lactobacillus salivarius, with a pan-genomic approach. Here, we isolated 21 L. salivarius strains composed of 6 strains isolated before the AGP prohibition (SBPs) and 15 strains isolated after the AGP prohibition (SAPs) at an interval of a decade, and the draft genomes were generated de novo...
2017: PloS One
Paul W Heron, Jurgen Sygusch
Fructose-1,6-bisphosphate (FBP) aldolase, a glycolytic enzyme, catalyzes the reversible and stereospecific aldol addition of dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde 3-phosphate (d-G3P) by an unresolved mechanism. To afford insight into the molecular determinants of FBP aldolase stereospecificity during aldol addition, a key ternary complex formed by DHAP and d-G3P, comprising 2% of the equilibrium population at physiological pH, was cryotrapped in the active site of Toxoplasma gondii aldolase crystals to high resolution...
December 1, 2017: Journal of Biological Chemistry
Yasuo Nagata, Narumi Mizuta, Akane Kanasaki, Kazunari Tanaka
BACKGROUND: Rare sugars including d-allulose, d-tagatose, and d-sorbose are present in limited quantities in nature; some of these rare sugars are now commercially produced using microbial enzymes. Apart from the anti-obesity and anti-hyperglycaemic activities of d-allulose, effects of these sugars on lipid metabolism have not been investigated. Therefore, we aimed to determine if and how d-tagatose and d-sorbose modulate lipid metabolism in rats. After feeding these rare sugars to rats, parameters on lipid metabolism were determined...
March 2018: Journal of the Science of Food and Agriculture
Ho Myeong Kim, Younho Song, Seung Gon Wi, Hyeun-Jong Bae
The rapid increase of agricultural waste is becoming a burgeoning problem and considerable efforts are being made by numerous researchers to convert it into a high-value resource material. Onion waste is one of the biggest issues in a world of dwindling resource. In this study, the potential of onion juice residue (OJR) for producing valuable rare sugar or bioethanol was evaluated. Purified Paenibacillus polymyxaL-arabinose isomerase (PPAI) has a molecular weight of approximately 53kDa, and exhibits maximal activity at 30°C and pH 7...
October 20, 2017: Journal of Biotechnology
Sofie Lagast, Hans De Steur, Joachim J Schouteten, Xavier Gellynck
Reducing sugar consumption is an important aspect in the prevention of and fight against obesity. A broader understanding of consumers' perceptions of low-calorie sweeteners is needed. This study examined two low-calorie sweeteners, tagatose and stevia, in comparison to sugar in dark chocolate. A total of 219 consumers participated in this study and rated overall liking and sensory attributes. Participants also listed their emotional conceptualisations upon consumption and were assessed on emotional eating behaviour and health and taste attitudes...
August 14, 2017: International Journal of Food Sciences and Nutrition
Mingxia Li, Rui Guo, Yang Jiao, Xiaofei Jin, Haiyan Zhang, Lianxuan Shi
Soybean is an important economic crop that is continually threatened by abiotic stresses, especially salt stress. Wild soybean is an important germplasm resource for the breeding of cultivated soybean. The root system plays a very important role in plant salt tolerance. To explore the salt tolerance-related mechanisms among Soja, we have demonstrated the seedling roots' growth and metabolomics in wild soybean, semi-wild soybean, and cultivated soybean under two types of salt stress by using gas chromatography-mass spectrometry...
2017: Frontiers in Plant Science
Muhammad Bilal, Hafiz M N Iqbal, Hongbo Hu, Wei Wang, Xuehong Zhang
Biomolecules like rare sugars and their derivatives are referred to as monosaccharides particularly uncommon in nature. Remarkably, many of them have various known physiological functions and biotechnological applications in cosmetics, nutrition, and pharmaceutical industries. Also, they can be exploited as starting materials for synthesizing fascinating natural bioproducts with significant biological activities. Regrettably, most of the rare sugars are quite expensive, and their synthetic chemical routes are both limited and economically unfeasible due to expensive raw materials...
June 29, 2017: Critical Reviews in Food Science and Nutrition
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