scholarly journals Degradation of the low-calorie sugar substitute 5-ketofructose by different bacteria

2021 ◽  
Author(s):  
Jacqueline Schiessl ◽  
Konrad Kosciow ◽  
Laura S. Garschagen ◽  
Juliane J. Hoffmann ◽  
Julia Heymuth ◽  
...  
Keyword(s):  
Public Awareness ◽  
Intestinal Bacteria ◽  
Gluconobacter Oxydans ◽  
Stationary Growth Phase ◽  
Amino Acid Sequences ◽  
Promising Alternative ◽  
Low Calorie ◽  
Key Points ◽  
Environmental Bacteria ◽  
Dietary Sugars

Abstract There is an increasing public awareness about the danger of dietary sugars with respect to their caloric contribution to the diet and the rise of overweight throughout the world. Therefore, low-calorie sugar substitutes are of high interest to replace sugar in foods and beverages. A promising alternative to natural sugars and artificial sweeteners is the fructose derivative 5-keto-D-fructose (5-KF), which is produced by several Gluconobacter species. A prerequisite before 5-KF can be used as a sweetener is to test whether the compound is degradable by microorganisms and whether it is metabolized by the human microbiota. We identified different environmental bacteria (Tatumella morbirosei, Gluconobacter japonicus LMG 26773, Gluconobacter japonicus LMG 1281, and Clostridium pasteurianum) that were able to grow with 5-KF as a substrate. Furthermore, Gluconobacter oxydans 621H could use 5-KF as a carbon and energy source in the stationary growth phase. The enzymes involved in the utilization of 5-KF were heterologously overproduced in Escherichia coli, purified and characterized. The enzymes were referred to as 5-KF reductases and belong to three unrelated enzymatic classes with highly different amino acid sequences, activities, and structural properties. Furthermore, we could show that 15 members of the most common and abundant intestinal bacteria cannot degrade 5-KF, indicating that this sugar derivative is not a suitable growth substrate for prokaryotes in the human intestine. Key points • Some environmental bacteria are able to use 5-KF as an energy and carbon source. • Four 5-KF reductases were identified, belonging to three different protein families. • Many gut bacteria cannot degrade 5-KF.

Direct cloning of genes encoding novel xylanases from the human gut

2005 ◽  
Vol 51 (3) ◽  
pp. 251-259 ◽  
Author(s):  
Hidenori Hayashi ◽  
Takashi Abe ◽  
Mitsuo Sakamoto ◽  
Hiroki Ohara ◽  
Toshimichi Ikemura ◽  
...  
Keyword(s):  
Intestinal Bacteria ◽  
Fecal Microbiota ◽  
Coli Strain ◽  
Amino Acid Sequences ◽  
Self Organizing Map ◽  
Human Gut ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Ph Range ◽  
Self Organizing

The aim of this study was to identify a novel 1,4-β-xylanase gene from the mixed genome DNA of human fecal bacteria without bacterial cultivation. Total DNA was isolated from a population of bacteria extracted from fecal microbiota. Using PCR, the gene fragments encoding 5 different family 10 xylanases (xyn10A, xyn10B, xyn10C, xyn10D, and xyn10E) were found. Amino acid sequences deduced from these genes were highly homologous with those of xylanases from anaerobic intestinal bacteria such as Bacteroides spp. and Prevotella spp. Self-organizing map (SOM) analysis revealed that xynA10 was classified into Bacteroidetes. To confirm that one of these genes encodes an active enzyme, a full-length xyn10A gene was obtained using nested primers specific to the internal fragments and random primers. The xyn10A gene encoding the xylanase Xyn10A consists of 1146 bp and encodes a protein of 382 amino acids and a molecular weight of 43 552. Xyn10A was a single module novel xylanase. Xyn10A was purified from a recombinant Escherichia coli strain and characterized. This enzyme was optimally active at 40 °C and stable up to 50 °C at pH 6.5 and over the pH range 4.0–11.0 at 25 °C. In addition, 2 ORFs (ORF1 and ORF2) were identified upstream of xyn10A. These results suggested that many unidentified xylanolytic bacteria exist in the human gut and may contribute to the breakdown of xylan which contains dietary fiber.Key words: xylanase, human gut, fecal microbiota, phylogenetic analysis, self-organizing map.

scholarly journals Are Biobased Plastics Green Alternatives?—A Critical Review

2021 ◽  
Vol 18 (15) ◽  
pp. 7729
Author(s):  
Diogo A. Ferreira-Filipe ◽  
Ana Paço ◽  
Armando C. Duarte ◽  
Teresa Rocha-Santos ◽  
Ana L. Patrício Silva
Keyword(s):  
Environmental Sustainability ◽  
Critical Review ◽  
Public Awareness ◽  
Building Blocks ◽  
Environmental Safety ◽  
Added Value ◽  
Economic Sectors ◽  
Promising Alternative ◽  
Biobased Polymers ◽  
Green Materials

Environmental sustainability is driving an intense search for “green materials”. Biobased plastics have emerged as a promising alternative. Their building blocks can now be obtained from diverse biomass, by-products, and organic residues due to the advances in biorefineries and bioprocessing technologies, decreasing the demand for fossil fuel resources and carbon footprint. Novel biobased polymers with high added value and improved properties and functionalities have been developed to apply diverse economic sectors. However, the real opportunities and risks of such novel biobased plastic solutions have raised scientific and public awareness. This paper provides a critical review on the recent advances in biobased polymers chemistry and emerging (bio)technologies that underpin their production and discusses the potential for biodegradation, recycling, environmental safety, and toxicity of these biobased solutions.

scholarly journals Identification of the yqhE andyafB Genes Encoding Two 2,5-Diketo-d-Gluconate Reductases inEscherichia coli

1999 ◽  
Vol 65 (8) ◽  
pp. 3341-3346 ◽  
Author(s):  
Do-Young Yum ◽  
Bong-Yong Lee ◽  
Jae-Gu Pan
Keyword(s):  
Biochemical Analysis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gluconobacter Oxydans ◽  
Amino Acid Sequences ◽  
Homologous Proteins ◽  
E Coli ◽  
Protein Databases ◽  
Molecular Weights ◽  
Genes Encoding

ABSTRACT The identification of a gene (yiaE) encoding 2-ketoaldonate reductase (2KR) in our previous work led to the hypothesis that Escherichia coli has other ketogluconate reductases including 2,5-diketo-d-gluconate reductase (25DKGR) and to study of the related ketogluconate metabolism. By using the deduced amino acid sequences of 5-diketo-d-gluconate reductase (5KDGR) of Gluconobacter oxydans and 25DKGR ofCorynebacterium sp., protein databases were screened to detect homologous proteins. Among the proteins of E. coli, an oxidoreductase encoded by yjgU and having 56% similarity to 5KDGR of G. oxydans and two hypothetical oxidoreductases encoded by yqhE and yafB and having 49.8 and 42% similarity, respectively, to 25DKGR ofCorynebacterium sp. were detected. Recently, theyjgU gene was identified as encoding 5KDGR and renamedidnO (C. Bausch, N. Peekhaus, C. Utz, T. Blais, E. Murray, T. Lowary, and T. Conway, J. Bacteriol. 180:3704–3710, 1998). The pathways involved in the metabolism of ketogluconate by E. coli have been predicted by biochemical analysis of purified enzymes and chemical analysis of the pathway intermediates. The gene products of yqhE and yafB were identified as 25DKGR-A, and 25DKGR-B, respectively, catalyzing the reduction of 25KDG to 2-keto-l-gulonate (2KLG). The native 25DKGR-A, 25DKGR-B, and 5KDGR had apparent molecular weights of about 30,000, 30,000, and 54,000, respectively. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels, all three enzymes showed protein bands with a molecular weight of about 29,000, which indicated that 25DKGR-A, 25DKGR-B, and 5KDGR may exist as monomeric, monomeric, and dimeric proteins, respectively. The optimum pHs for reduction were 7.5, 7.0, and 8.0, respectively. The 5KDGR was active with NADH, whereas 25DKGR-A and 25DKGR-B were active with NADPH as a preferred electron donor. 25DKG can be converted to 5KDG by 2KR, which is then reduced tod-gluconate by 5KDGR. The pathways were compared with those of Erwinia sp. and Corynebacterium sp. A BLAST search of published and incomplete microbial genome sequences revealed that the ketogluconate reductases and their related metabolism may be widespread in many species.

scholarly journals Growth of Carbon Nanocoils by Porous α-Fe2O3/SnO2 Catalyst and Its Buckypaper for High Efficient Adsorption

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongpeng Zhao ◽  
Jianzhen Wang ◽  
Hui Huang ◽  
Tianze Cong ◽  
Shuaitao Yang ◽  
...  
Keyword(s):  
High Purity ◽  
Large Scale ◽  
Blue Dye ◽  
Adsorption Efficiency ◽  
Promising Alternative ◽  
Practical Applications ◽  
Key Points ◽  
High Efficient ◽  
Reported Data ◽  
Efficient Adsorbent

AbstractHigh-purity (99%) carbon nanocoils (CNCs) have been synthesized by using porous α-Fe2O3/SnO2 catalyst. The yield of CNCs reaches 9,098% after a 6 h growth. This value is much higher than the previously reported data, indicating that this method is promising to synthesize high-purity CNCs on a large scale. It is considered that an appropriate proportion of Fe and Sn, proper particle size distribution, and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs. Benefiting from the high-purity preparation, a CNC Buckypaper was successfully prepared and the electrical, mechanical, and electrochemical properties were investigated comprehensively. Furthermore, as one of the practical applications, the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%. This study provides a facile and economical route for preparing high-purity CNCs, which is suitable for large-quantity production. Furthermore, the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.

scholarly journals Investigating the Product Profiles and Structural Relationships of New Levansucrases with Conventional and Non-Conventional Substrates

2020 ◽  
Vol 21 (15) ◽  
pp. 5402
Author(s):  
Andrea Hill ◽  
Salwa Karboune ◽  
Tarun J. Narwani ◽  
Alexandre G. de Brevern
Keyword(s):  
Food Industry ◽  
Genome Mining ◽  
Gluconobacter Oxydans ◽  
Amino Acid Sequences ◽  
Structural Elements ◽  
Initial Screening ◽  
Donor Molecule ◽  
Structural Relationships ◽  
High Degree ◽  
Homology Models

The synthesis of complex oligosaccharides is desired for their potential as prebiotics, and their role in the pharmaceutical and food industry. Levansucrase (LS, EC 2.4.1.10), a fructosyl-transferase, can catalyze the synthesis of these compounds. LS acquires a fructosyl residue from a donor molecule and performs a non-Lenoir transfer to an acceptor molecule, via β-(2→6)-glycosidic linkages. Genome mining was used to uncover new LS enzymes with increased transfructosylating activity and wider acceptor promiscuity, with an initial screening revealing five LS enzymes. The product profiles and activities of these enzymes were examined after their incubation with sucrose. Alternate acceptor molecules were also incubated with the enzymes to study their consumption. LSs from Gluconobacter oxydans and Novosphingobium aromaticivorans synthesized fructooligosaccharides (FOSs) with up to 13 units in length. Alignment of their amino acid sequences and substrate docking with homology models identified structural elements causing differences in their product spectra. Raffinose, over sucrose, was the preferred donor molecule for the LS from Vibrio natriegens, N. aromaticivorans, and Paraburkolderia graminis. The LSs examined were found to have wide acceptor promiscuity, utilizing monosaccharides, disaccharides, and two alcohols to a high degree.

scholarly journals Investigation of Spa Pools Associated with Lung Disorders Caused by Mycobacterium avium Complex in Immunocompetent Adults

2004 ◽  
Vol 70 (8) ◽  
pp. 4906-4910 ◽  
Author(s):  
Richard Lumb ◽  
Richard Stapledon ◽  
Andrew Scroop ◽  
Peter Bond ◽  
David Cunliffe ◽  
...  
Keyword(s):  
Lung Disease ◽  
Mycobacterium Avium ◽  
Mycobacterium Avium Complex ◽  
Public Awareness ◽  
Health Departments ◽  
Fourth Case ◽  
Environmental Bacteria ◽  
Immunocompetent Adults ◽  
Culture Positive

ABSTRACT Three cases of Mycobacterium avium complex-related lung disorders were associated with two poorly maintained spa pools by genotypic investigations. Inadequate disinfection of the two spas had reduced the load of environmental bacteria to less than 1 CFU/ml but allowed levels of M. avium complex of 4.3 × 104 and 4.5 × 103 CFU/ml. Persistence of the disease-associated genotype was demonstrated in one spa pool for over 5 months until repeated treatments with greater than 10 mg of chlorine per liter for 1-h intervals eliminated M. avium complex from the spa pool. A fourth case of Mycobacterium avium complex-related lung disease was associated epidemiologically but not genotypically with another spa pool that had had no maintenance undertaken. This spa pool contained low numbers of mycobacteria by smear and was culture positive for M. avium complex, and the nonmycobacterial organism count was 5.2 × 106 CFU/ml. Public awareness about the proper maintenance of private (residential) spa pools must be promoted by health departments in partnership with spa pool retailers.

scholarly journals Development of next-generation sequencing-based sterility test

2020 ◽  
Author(s):  
Jianhui Yue ◽  
Chao Chen ◽  
Xiaohuan Jing ◽  
Qiwang Ma ◽  
Bo Li ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Multiple Displacement Amplification ◽  
High Sensitivity ◽  
Next Generation ◽  
Promising Alternative ◽  
Sterility Testing ◽  
Sterility Test ◽  
Microorganism Identification ◽  
Environmental Bacteria ◽  
Generation Sequencing

AbstractThe sterility testing methods described in pharmacopoeias require an incubation period of 14 days to obtain analysis results. An alternative method that can significantly shorten the detection time and improve the accuracy is in urgent need to meet the sterility testing requirements of regenerative medicine products with a short shelf life. In this study, we developed the next-generation sequencing-based sterility test (NGSST) based on sequencing and multiple displacement amplification. The NGSST can be finished within 48 hours with five steps including whole genome amplification, sequencing, alignment, sterility testing report, and microorganism identification. We use RPKM ratio to minorize the influence of environmental bacteria and determine its cutoff based AUC curve. The NGSST showed high sensitivity in reporting contaminates at 0.1 CFU in supernatant of biological product or 1 CFU in cell suspension. Furthermore, we identified microorganisms in 5 primary umbilical cord mesenchymal stem cell samples that were tested positive by BacT/ALERTR 3D. Overall, the NGSST can serve as a promising alternative for sterility testing of biological products.

scholarly journals Gluconobacter oxydans Knockout Collection Finds Improved Rare Earth Element Extraction

2021 ◽  
Author(s):  
Alexa M. Schmitz ◽  
Brooke Pian ◽  
Sean Medin ◽  
Matthew C. Reid ◽  
Mingming Wu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Acid Production ◽  
Glucose Dehydrogenase ◽  
Gluconobacter Oxydans ◽  
Extraction Methods ◽  
Promising Alternative ◽  
Energy Technologies ◽  
Thermochemical Processes ◽  
Membrane Bound ◽  
Critical Components

Rare earth elements (REE) are critical components of our technological society and essential for renewable energy technologies. Traditional thermochemical processes to extract REE from mineral ores or recycled materials are costly and environmentally harmful, and thus more sustainable extraction methods require exploration. Bioleaching offers a promising alternative to conventional REE extraction, and is already used to extract 5% of the world's gold, and approximately 15% of the world's copper supply. However, the performance of REE bioleaching lags far behind thermochemical processes. Despite this, to the best of our knowledge no genetic engineering strategies have yet been used to enhance REE bioleaching, and little is known of the genetics that confer this capability. Here we build a whole genome knockout collection for Gluconobacter oxydans B58, one of the most promising organisms for REE bioleaching, and use it to comprehensively characterize the genomics of REE bioleaching. In total, we find 304 genes that notably alter production of G. oxydans' acidic biolixiviant, including 165 that hold up under statistical comparison with wild-type. The two most impactful groups of genes involved in REE bioleaching have opposing influences on acid production and REE bioleaching. Disruption of genes underlying synthesis of the cofactor pyrroloquinoline quinone (PQQ) and the PQQ-dependent membrane-bound glucose dehydrogenase all but eliminates bioleaching. In contrast, disruption of the phosphate-specific transport system accelerates acid production and enhances bioleaching. We identified 6 disruption mutants, that increase bioleaching by at least 11%. Most significantly, disruption of pstC, encoding part of the phosphate -specific transporter, pstSCAB, enhances bioleaching by 18%. Taken together, these results give a comprehensive roadmap for engineering multiple sites in the genome of G. oxydans to further increase its bioleaching efficiency.

scholarly journals SURVEYING, MODELING AND 3D REPRESENTATION OF A WRECK FOR DIVING PURPOSES: CARGO SHIP “VERA”

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 399-403
Author(s):  
A. Ktistis ◽  
P. Tokmakidis ◽  
K. Papadimitriou
Keyword(s):  
3D Model ◽  
Low Cost ◽  
Public Awareness ◽  
Ex Situ ◽  
Key Points ◽  
Recreational Diving ◽  
3D Representation ◽  
3D Representations ◽  
Cultural Features

This paper presents the results from an underwater recording of the stern part of a contemporary cargo-ship wreck. The aim of this survey was to create 3D representations of this wreck mainly for recreational diving purposes. The key points of this paper are: a) the implementation of the underwater recording at a diving site; b) the reconstruction of a 3d model from data that have been captured by recreational divers; and c) the development of a set of products to be used by the general public for the ex situ presentation or for the <i>in situ</i> navigation. The idea behind this project is to define a simple and low cost procedure for the surveying, modeling and 3D representation of a diving site. The perspective of our team is to repeat the proposed methodology for the documentation and the promotion of other diving sites with cultural features, as well as to train recreational divers in underwater surveying procedures towards public awareness and community engagement in the maritime heritage.

Structure and Interaction of Protamine by Dark Field Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 160-161
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Amino Acid Sequences ◽  
Dimensional Structure ◽  
3 Dimensional ◽  
Field Electron ◽  
Proposed Model ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Positively Charged

It has been shown for some time that it is possible to obtain images of small unstained proteins, with a resolution of approximately 5Å using dark field electron microscopy (1,2). Applying this technique, we have observed a uniformity in size and shape of the 2-dimensional images of pure specimens of fish protamines (salmon, herring (clupeine, Y-l) and rainbow trout (Salmo irideus)). On the basis of these images, a model for the 3-dimensional structure of the fish protamines has been proposed (2).The known amino acid sequences of fish protamines show stretches of positively charged arginines, separated by regions of neutral amino acids (3). The proposed model for protamine structure (2) consists of an irregular, right-handed helix with the segments of adjacent arginines forming the loops of the coil.

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