scholarly journals Cell-based and cell-free biocatalysis for the production of d-glucaric acid

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Lu-Zhou Chen ◽  
Si-Ling Huang ◽  
Jin Hou ◽  
Xue-Ping Guo ◽  
Feng-Shan Wang ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
De Novo ◽  
Value Added ◽  
Host Cells ◽  
Efficient Production ◽  
Glucaric Acid ◽  
A Value ◽  
Potential Applications ◽  
Increasing Demand

Abstractd-Glucaric acid (GA) is a value-added chemical produced from biomass, and has potential applications as a versatile platform chemical, food additive, metal sequestering agent, and therapeutic agent. Marketed GA is currently produced chemically, but increasing demand is driving the search for eco-friendlier and more efficient production approaches. Cell-based production of GA represents an alternative strategy for GA production. A series of synthetic pathways for GA have been ported into Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris, respectively, and these engineered cells show the ability to synthesize GA de novo. Optimization of the GA metabolic pathways in host cells has leapt forward, and the titer and yield have increased rapidly. Meanwhile, cell-free multi-enzyme catalysis, in which the desired pathway is constructed in vitro from enzymes and cofactors involved in GA biosynthesis, has also realized efficient GA bioconversion. This review presents an overview of studies of the development of cell-based GA production, followed by a brief discussion of potential applications of biosensors that respond to GA in these biosynthesis routes.

scholarly journals Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

2021 ◽  
pp. eabd6990
Author(s):  
Sang Il Kim ◽  
Jinsung Noh ◽  
Sujeong Kim ◽  
Younggeun Choi ◽  
Duck Kyun Yoo ◽  
...  
Keyword(s):  
B Cells ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Binding Domain ◽  
Host Cells ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

Cellular and immunological basis of the host-parasite relationship during infection withNeospora caninum

Parasitology ◽  
2006 ◽  
Vol 133 (3) ◽  
pp. 261-278 ◽  
Author(s):  
A. HEMPHILL ◽  
N. VONLAUFEN ◽  
A. NAGULESWARAN
Keyword(s):  
Host Cell ◽  
Cell Biology ◽  
Neospora Caninum ◽  
Host Cells ◽  
Term Survival ◽  
Prevention Of Infection ◽  
Parasite Relationship ◽  
Potential Applications

Neospora caninumis an apicomplexan parasite that is closely related toToxoplasma gondii, the causative agent of toxoplasmosis in humans and domestic animals. However, in contrast toT. gondii, N. caninumrepresents a major cause of abortion in cattle, pointing towards distinct differences in the biology of these two species. There are 3 distinct key features that represent potential targets for prevention of infection or intervention against disease caused byN. caninum. Firstly, tachyzoites are capable of infecting a large variety of host cellsin vitroandin vivo. Secondly, the parasite exploits its ability to respond to alterations in living conditions by converting into another stage (tachyzoite-to-bradyzoite orvice versa). Thirdly, by analogy withT. gondii, this parasite has evolved mechanisms that modulate its host cells according to its own requirements, and these must, especially in the case of the bradyzoite stage, involve mechanisms that ensure long-term survival of not only the parasite but also of the host cell. In order to elucidate the molecular and cellular bases of these important features ofN. caninum, cell culture-based approaches and laboratory animal models are being exploited. In this review, we will summarize the current achievements related to host cell and parasite cell biology, and will discuss potential applications for prevention of infection and/or disease by reviewing corresponding work performed in murine laboratory infection models and in cattle.

scholarly journals Francisella tularensis ΔpyrF Mutants Show that Replication in Nonmacrophages Is Sufficient for Pathogenesis In Vivo

2010 ◽  
Vol 78 (6) ◽  
pp. 2607-2619 ◽  
Author(s):  
Joseph Horzempa ◽  
Dawn M. O'Dee ◽  
Robert M. Q. Shanks ◽  
Gerard J. Nau
Keyword(s):  
Francisella Tularensis ◽  
De Novo ◽  
Human Fibroblasts ◽  
Host Cells ◽  
Hek 293 ◽  
293 Cells ◽  
Animal Infection ◽  
Schu S4

ABSTRACT The pathogenesis of Francisella tularensis has been associated with this bacterium's ability to replicate within macrophages. F. tularensis can also invade and replicate in a variety of nonphagocytic host cells, including lung and kidney epithelial cells and hepatocytes. As uracil biosynthesis is a central metabolic pathway usually necessary for pathogens, we characterized ΔpyrF mutants of both F. tularensis LVS and Schu S4 to investigate the role of these mutants in intracellular growth. As expected, these mutant strains were deficient in de novo pyrimidine biosynthesis and were resistant to 5-fluoroorotic acid, which is converted to a toxic product by functional PyrF. The F. tularensis ΔpyrF mutants could not replicate in primary human macrophages. The inability to replicate in macrophages suggested that the F. tularensis ΔpyrF strains would be attenuated in animal infection models. Surprisingly, these mutants retained virulence during infection of chicken embryos and in the murine model of pneumonic tularemia. We hypothesized that the F. tularensis ΔpyrF strains may replicate in cells other than macrophages to account for their virulence. In support of this, F. tularensis ΔpyrF mutants replicated in HEK-293 cells and normal human fibroblasts in vitro. Moreover, immunofluorescence microscopy showed abundant staining of wild-type and mutant bacteria in nonmacrophage cells in the lungs of infected mice. These findings indicate that replication in nonmacrophages contributes to the pathogenesis of F. tularensis.

Synthesis of Lignin-Based Polyurethanes: A Mini-Review

2019 ◽  
Vol 16 (4) ◽  
pp. 345-352 ◽  
Author(s):  
Júlia Rocha Gouveia ◽  
Cleber Lucius da Costa ◽  
Lara Basílio Tavares ◽  
Demetrio Jackson dos Santos
Keyword(s):  
Lignin Content ◽  
Thermoplastic Polyurethane ◽  
Value Added ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
A Value ◽  
Reactive Groups ◽  
Potential Applications ◽  
Renewable Raw Material ◽  
Direct Incorporation

Lignin is a natural polymer composed primarily of phenylpropanoid structures with an abundance of reactive groups: aliphatic and aromatic hydroxyls, phenols, and carbonyls. Considering the large quantity of hydroxyl groups, lignin has significant potential as a replacement for petroleum-based polyols in polyurethane (PU) synthesis and as a value-added, renewable raw material for this purpose. Several methods of lignin-based polyurethane synthesis are reviewed in this paper for reactive and thermoplastic systems: direct lignin incorporation, chemical lignin modification and depolymerization. Despite the unmodified lignin low reactivity towards diisocyanates, its direct incorporation as polyol generates highly brittle PUs, but with proper performance when applied as adhesive for wood. PU brittleness can be reduced employing polyols obtained from lignin/chain extender blends, in which glass transition temperature (Tg), mechanical properties and PU homogeneity are strongly affected by lignin content. The potential applications of lignin can be enhanced by lignin chemical modifications, including oxyalkylation and depolymerization, improving polyurethanes properties. Another PU category, lignin- based thermoplastic polyurethane (LTPU) synthesis, emerges as a sustainable alternative and is also presented in this work.

The Defence by Design framework: Conceptual foundations and potential applications

2021 ◽  
Vol 7 (2) ◽  
pp. 211-232 ◽  
Author(s):  
Cara Wrigley ◽  
Harjit Rana ◽  
Peta Hinton ◽  
Genevieve Mosely
Keyword(s):  
Design Thinking ◽  
Value Added ◽  
Design Framework ◽  
New Approach ◽  
A Value ◽  
Potential Applications ◽  
Defence Strategy ◽  
Military Objective ◽  
Conceptual Foundations

With rapid advancements in technology radically impacting and changing current ways of working globally, many industries and sectors, including the Defence force, are implementing new approaches to respond to and address these challenges. Design thinking is one approach to assist in this response, as it provides a novel process for solving complex problems. This article presents a specific design approach for addressing contextual Defence problems in the form of a design thinking framework based on a review of the existing literature concerning design and Defence. The article contends with the role of design as a value-added methodology in Defence strategy and development, and it reports on a unique set of design thinking capabilities for a Defence-specific context that are not only essential for the implementation of a design-led approach to innovation but are of great assistance in overcoming its associated challenges. The Defence by Design framework works with an identified military objective that, when applied, overcomes the natural bias that Defence personnel may exhibit during routine gaps and opportunities analysis. By detailing the different stages of the framework, and demonstrating their iterative nature, through the documentation of a working example – ‘Man Overboard’ – this article presents a new approach yet to be realized in Defence globally.

scholarly journals ISOLATION OF GLUCOSAMINE HCL FROM SCYLLA PARAMAMOSAIN AND DETERMINATION BY HPLC

2019 ◽  
Vol 81 (5) ◽  
Author(s):  
Astrid Kusuma Putri ◽  
Sugijanto Kartosentono ◽  
Noor Erma Nasution Sugijanto
Keyword(s):  
High Performance ◽  
Negative Impact ◽  
Economic Value ◽  
Value Added ◽  
Scylla Paramamosain ◽  
Glucosamine Hydrochloride ◽  
Treatment Groups ◽  
A Value ◽  
Potential Applications ◽  
Naoh Solution

Scylla paramamosain is one of crustaceans that has economic value in Indonesia. About 40-50% of the total weight of crustaceans goes as waste after being processed to be human food. The Crustacean waste needs to be reduced in order to minimize the negative impact on the environment. Whereas products derived from crustacean shell also has medical value (e.g. Chitosan, Glucosamine HCl). Glucosamine is an amino monosaccharide acting as a substrate for the production of aggrecan and proteoglycans and thus have therapeutic activity in osteoarthritis. The present study has been aimed to prepare glucosamine hydrochloride (Glu-HCl) from S. paramamosain waste by acid hydrolysis in four treatment groups and their quantitation by high-performance liquid chromatography (HPLC). The best condition from this experiment is shell deproteination with 3% NaOH solution (w/v 1:6), at 85ºC, for 30 minutes, demineralisation with 1N HCl (w/v 1:10), at 75ºC, for 1.5 hours, depigmentation with NaClO 0.38%, at room temperature, for 1 hour, and hydrolysis with conc. HCl (w/v 1:20), at 85ºC, for 18 minutes, resulted in the yield of 6.15 ± 0.62% and quantitation by HPLC analysis of obtained glucosamine hydrochloride was 98.48 ± 0.74%. Further, this study describes the recycling of S. paramamosain waste to a value-added product which is having potential applications in the field of food and medicine.

scholarly journals Novel In Vivo-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered Gluconacetobacter xylinus

2010 ◽  
Vol 76 (18) ◽  
pp. 6257-6265 ◽  
Author(s):  
Vikas Yadav ◽  
Bruce J. Paniliatis ◽  
Hai Shi ◽  
Kyongbum Lee ◽  
Peggy Cebe ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
De Novo ◽  
Biomass Conversion ◽  
Gluconacetobacter Xylinus ◽  
The Poor ◽  
Wide Range ◽  
Potential Applications ◽  
Rapid Hydrolysis

ABSTRACT Despite excellent biocompatibility and mechanical properties, the poor in vitro and in vivo degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce N-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during de novo synthesis from Gluconacetobacter xylinus. The cellulose produced from these engineered cells (modified bacterial cellulose [MBC]) was evaluated and compared with cellulose produced from normal cells (bacterial cellulose [BC]). High GlcNAc content and lower crystallinity in MBC compared to BC make this a multifunctional bioengineered polymer susceptible to lysozyme, an enzyme widespread in the human body, and to rapid hydrolysis by cellulase, an enzyme commonly used in biomass conversion. Degradability in vivo was demonstrated in subcutaneous implants in mice, where modified cellulose was completely degraded within 20 days. We provide a new route toward the production of a family of tailorable modified cellulosic biopolymers that overcome the longstanding limitation associated with the poor degradability of cellulose for a wide range of potential applications.

scholarly journals Carbonic Anhydrase Is Essential for Streptococcus pneumoniae Growth in Environmental Ambient Air

2010 ◽  
Vol 192 (15) ◽  
pp. 4054-4062 ◽  
Author(s):  
Peter Burghout ◽  
Lorelei E. Cron ◽  
Henrik Gradstedt ◽  
Beatriz Quintero ◽  
Elles Simonetti ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Carbonic Anhydrase ◽  
Unsaturated Fatty Acids ◽  
De Novo ◽  
Ambient Air ◽  
Host Cells ◽  
Ambient Conditions ◽  
Growth And Survival ◽  
Cellular Processes

ABSTRACT The respiratory tract pathogen Streptococcus pneumoniae needs to adapt to the different levels of carbon dioxide (CO2) it encounters during transmission, colonization, and infection. Since CO2 is important for various cellular processes, factors that allow optimal CO2 sequestering are likely to be important for pneumococcal growth and survival. In this study, we showed that the putative pneumococcal carbonic anhydrase (PCA) is essential for in vitro growth of S. pneumoniae under the CO2-poor conditions found in environmental ambient air. Enzymatic analysis showed that PCA catalyzes the reversible hydration of CO2 to bicarbonate (HCO3 −), an essential step to prevent the cellular release of CO2. The addition of unsaturated fatty acids (UFAs) reversed the CO2-dependent in vitro growth inhibition of S. pneumoniae strains lacking the pca gene (Δpca), indicating that PCA-mediated CO2 fixation is at least associated with HCO3 −-dependent de novo biosynthesis of UFAs. Besides being necessary for growth in environmental ambient conditions, PCA-mediated CO2 fixation pathways appear to be required for intracellular survival in host cells. This effect was especially pronounced during invasion of human brain microvascular endothelial cells (HBMEC) and uptake by murine J774 macrophage cells but not during interaction of S. pneumoniae with Detroit 562 pharyngeal epithelial cells. Finally, the highly conserved pca gene was found to be invariably present in both CO2-independent and naturally circulating CO2-dependent strains, suggesting a conserved essential role for PCA and PCA-mediated CO2 fixation pathways for pneumococcal growth and survival.

scholarly journals Identification of a bacteria-produced benzisoxazole with antibiotic activity against multi-drug resistant Acinetobacter baumannii

2021 ◽  
Author(s):  
Robert W. Deering ◽  
Kristen E. Whalen ◽  
Ivan Alvarez ◽  
Kathryn Daffinee ◽  
Maya Beganovic ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Metabolic Pathways ◽  
Pathogenic Bacteria ◽  
Antibacterial Agents ◽  
De Novo ◽  
Drug Resistant ◽  
Antibacterial Effects ◽  
Naturally Occurring ◽  
Molecular Modeling Studies

AbstractThe emergence of multi-drug resistant pathogenic bacteria represents a serious and growing threat to national healthcare systems. Most pressing is an immediate need for the development of novel antibacterial agents to treat Gram-negative multi-drug resistant infections, including the opportunistic, hospital-derived pathogen, Acinetobacter baumannii. Herein we report a naturally occurring 1,2-benzisoxazole with minimum inhibitory concentrations as low as 6.25 μg ml−1 against clinical strains of multi-drug resistant A. baumannii and investigate its possible mechanisms of action. This molecule represents a new chemotype for antibacterial agents against A. baumannii and is easily accessed in two steps via de novo synthesis. In vitro testing of structural analogs suggest that the natural compound may already be optimized for activity against this pathogen. Our results demonstrate that supplementation of 4-hydroxybenzoate in minimal media was able to reverse 1,2-benzisoxazole’s antibacterial effects in A. baumannii. A search of metabolic pathways involving 4-hydroxybenzoate coupled with molecular modeling studies implicates two enzymes, chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyltransferase, as promising leads for the target of 3,6-dihydroxy-1,2-benzisoxazole.

scholarly journals Utilization of Agricultural Waste for the Production of Xylooligosaccharides Using Response Surface Methodology and Their In Vitro Prebiotic Efficacy

2021 ◽  
Author(s):  
Nagamani Kathiresan ◽  
Lingesh Gopal ◽  
Vijay Karuppiah ◽  
Renuka Naveenethan ◽  
David Ravindran Abraham ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Enzymatic Hydrolysis ◽  
Response Surface ◽  
Sugarcane Bagasse ◽  
Agricultural Waste ◽  
Relative Yield ◽  
Value Added ◽  
A Value ◽  
Hydrolysis Of

Abstract Air pollution is a prominent problem recently faced in various parts of India due to the burning of stubbles (coconut husk, corn cob, paddy stubbles, sugarcane bagasse, etc.) which are rich in a lignocellulosic component that can be converted into a prebiotic known as Xylooliogsaccaride (XOS). They can be produced by autohydrolysis, acid hydrolysis and enzymatic hydrolysis of xylan. In the present study, Xylan was extracted from sugarcane bagasse using two alkalis (NaOH and KOH) and the yield was compared. Xylooligosaccharide produced by enzymatic hydrolysis and their factors influencing the yield were optimized using Response Surface Methodology. Xylan and Xylooligosaccharide was characterized by FTIR, NMR, XRD, TGA and ESI-MS. Xylooligosaccharides was investigated for their prebiotic potential by in vitro study. The maximum (Relative yield of 86%) yield of xylan was observed in 20% of NaOH. Xylan peaks at 3762cm− 1, 3347 cm− 1, 2917cm− 1 represents the OH and CH stretching of xylan. The main signals at 4.26 (H-1), 3.19 (H-2), 3.59 (H-3), 3.63 (H-4) and 3.98 (H-5) ppm determines the existence of xylan. The higher amount of XOS is pH 4.75, temperature 45°C, enzyme 4U/ml and for time of 16h. The spectrum of 5.0-5.40ppm and 4.30-4.60ppm represents the α anomeric and β anomeric protons in XOS. They are resistant digested and the reaching percentage to the intestine is 95% unhydrolyzed. The maximum prebiotic index was noted in L.plantarum (1.92) and L.fermentum (1.61). The highest prebiotic index and score was observed in L.plantarum (1.9) and L.fermentum (17). The maximum bacteriocin production of Enterococcus faecium against E.fecalis (13mm) and Streptococcus pyogenes (11mm). Therefore, utilization of agricultural residues for a value-added product not only shows a great impact on environmental issues but also could double the farmer’s income

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