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Enzymes from Extreme Environments

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198306 Year: Pages: 103 DOI: 10.3389/978-2-88919-830-6 Language: English
Publisher: Frontiers Media SA
Subject: Biotechnology --- General and Civil Engineering
Added to DOAB on : 2016-01-19 14:05:46
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Enzymes are nature’s biocatalysts empowered with high catalytic power and remarkable substrate specificity. Enzymes perform a wide range of functions throughout nature, and guide the biochemistry of life with great precision. The majority of enzymes perform under conditions considered normal for mesophilic, neutrophilic, terrestrial microorganisms. However, the Earth’s biosphere contains several regions that are extreme in comparison, such as hypersaline lakes and pools, hydrothermal vents, cold oceans, dry deserts and areas exposed to intensive radiation. These areas are inhabited by a large number of extremophilic microorganisms which produce enzymes capable of functioning in unusual conditions. There is an increasing biotechnological and industrial demand for enzymes stable and functioning in harsh conditions, and over the past decade screening for, isolation and production of enzymes with unique and extreme properties has become one of the foremost areas of biotechnology research. The development of advanced molecular biology tools has facilitated the quest for production of enzymes with optimized and extreme features. These tools include large-scale screening for potential genes using metagenomics, engineering of enzymes using computational techniques and site-directed mutagenesis and molecular evolution techniques. The goal of this Research Topic is to present reports on latest advances in enzymes from all types of extreme environments. Contributions dealing with isolation of enzymes from extremophilic microorganisms or directly from natural environments, screening for and expression of enzymes with extreme properties using metagenomic approaches are welcome. In addition, contributions dealing with all forms of biocatalyst production and improvement are welcome, such as fermentation technology, protein engineering, directed evolution, rational design, and immobilization techniques.

Vitamin C and Human Health

ISBN: 9783906980614 9783906980621 Year: Pages: 236 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Added to DOAB on : 2015-01-12 11:52:06
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Ascorbic acid is a small, simple, water soluble molecule, synthesised by most plants and animals, with the exception of humans and some animal species due to mutations in the gene encoding the terminal enzyme in the biosynthetic pathway. For humans, it is thus a vitamin (vitamin C) that must be obtained from the diet, with complete deficiency resulting in the fatal disease scurvy. Many functions have been attributed to this fascinating molecule and, despite nearly 90 years of research since its discovery, new roles are still being uncovered, including recent discoveries that it acts as a regulator of epigenetic marks and transcription factors (1). In this volume we begin with a review by Michels and Frei on specific factors that need to be taken into consideration when carrying out vitamin C research. Translational research normally comprises a progression from in vitro/cell culture studies to animal models and finally to clinical trials. At each of these stages, there are requirements specific to vitamin C research that need to be integrated into study designs and this review describes these in detail. [...]

Cerebral endothelial and glial cells are more than bricks in the Great Wall of the brain: Insights into the way the blood-brain barrier actually works (Celebrating the centenary of Goldman's experiments)

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195725 Year: Pages: 186 DOI: 10.3389/978-2-88919-572-5 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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When Ehrlich discovered the first evidence of the blood-brain barrier in 1885, he probably did not perceive the Great Wall that remained hidden from consciousness inside the central nervous system. Ehrlich had observed that acidic vital dyes did not stain the brain if they were injected into the blood stream. A century ago (1913), Goldman showed that the injection of trypan blue in the cerebrospinal fluid stained only the brain, but not the other organs. For almost a century it was thought that the blood-brain barrier (BBB) consisted in a physical barrier, resulting from the restricted permeability of the cerebral endothelial cell layer, as they are joined by tight junctions. However, as scientists are always looking for news in what is already discovered, in the end of the 20th century we had evidences that cerebral endothelial and glial cells express several drug metabolizing enzymes consisting in a second protection system: a metabolic barrier. Furthermore, the drugs and their metabolites must overcome the activity of several multidrug resistance proteins that function as ATP-dependent efflux pumps, consisting in the third line of defence: the active barrier. Therefore, the way the BBB actually works should be better explained. Several endogenous compounds, as well as xenobiotics, may be activated by enzymes of the metabolic barrier, generating reactive oxygen species that could damage neurons. Therefore, endothelial and glial cells possess endogenous protecting compounds and enzymes against oxidants, consisting in an antioxidant barrier. When all these systems fail, glial cells, mainly microglia, secrete cytokines in an attempt to crosstalk with defence cells asking for help, which consists in an immune barrier. In cerebral regions that are devoid of the physical barrier, such as circumventricular organs, the metabolic, active, antioxidant and immune barriers are reinforced. It is important to understand how cells involved in the BBB interact with one another and the dynamic mechanisms of their functions. This Research Topic published in this e-Book considers recent highlights in BBB structure, cell and molecular biology, biotransformation, physiology, pathology, pharmacology, immunology and how these basic knowledges can be applied in drug discovery and clinical researches, rewriting what is already written, and paving the way that goes to the Great Wall in the Frontiers of the Brain in this new century that is just beginning.

Plant cell wall in pathogenesis, parasitism and symbiosis

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194421 Year: Pages: 150 DOI: 10.3389/978-2-88919-442-1 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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The cell wall is a complex structure mainly composed of cellulose microfibrils embedded in a cohesive hemicellulose and pectin matrix. Cell wall structural proteins, enzymes and their inhibitors are also essential components of plant cell walls. They are involved in the cross-link of cell wall polysaccharides, wall structure, and the perception and signaling of defense-related elicitors at the cell surface. In the outer part of the epidermal cells, the polysaccharides are coated by the cuticle, consisting of hydrophobic cutin, suberin and wax layers. Lignin, a macromolecule composed of highly cross-linked phenolic molecules, is a major component of the secondary cell wall. The cell wall is the first cell structure on which interactions between plants and a wide range of other organisms, including insects, nematodes, pathogenic or symbiotic micro-organisms take place. It not only represents a barrier that limits access to the cellular contents that provide a rich nutrient source for pathogens but serves as a source of elicitors of plant defense responses released upon partial enzymatic degradation of wall polysaccharides during infection. Modification of the plant cell wall can also occur at the level of plasmodesmata during virus infection as well as during abiotic stresses. The fine structure and composition of the plant cell wall as well as the regulation of its biosynthesis can thus strongly influence resistance and susceptibility to pathogens. This Research Topic provides novel insights and detailed overviews on the dynamics of the plant cell wall in plant defence, parasitism and symbiosis and describes experimental approaches to study plant cell wall modifications occurring during interaction of plants with different organisms.

Marine Biomolecules

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196616 Year: Pages: 97 DOI: 10.3389/978-2-88919-661-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Chemistry (General) --- General and Civil Engineering --- Biotechnology
Added to DOAB on : 2016-08-16 10:34:25
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Oceans include the greatest extremes of pressure, temperature and light, and habitats can range from tropical waters to ocean trenches, several kilometers below sea level at high pressure. With its 70% of the surface of our planet marine ecosystem still remains largely unexplored, understudied and underexploited in comparison with terrestrial ecosystems, organisms and bioprocesses. The biological adaptation of marine organisms to a wide range of environmental conditions in the specific environment (temperature, salinity, tides, pressure, radiation, light, etc.) has made them an enormous reservoir of interesting biological material for both basic research and biotechnological improvements. As a consequence marine ecosystem is valued as a source of enzymes and other biomolecules exhibiting new functions and activities to fulfill human needs. Indeed, in recent years it has been recognised as an untapped source of novel enzymes and metabolites even though, with regard to the assignment of precise biological functions to genes, proteins and enzymes, it is still considered as the least developed. Using metagenomics to recover genetic material directly from environmental samples, this biogenetic diversification can be accessed but despite the contributions from metagenomic technologies the new field requires major improvements. A few words on the complexity of marine environments should be added here. This complexity ranges from symbiotic relationships to biology and chemistry of defence mechanisms and from chemoecology of marine invasions up to the strategies found in prokaryotes to adapt to extreme environments. The interdisciplinary study of this complexity will enable researchers to find an arsenal of enzymes and pathways greatly demanded in biotechnological applications. As far as marine enzymes are concerned they may carry novel chemical and stereochemical properties, thus biocatalytically oriented studies (testing of suitable substrates, appropriate checking of reaction conditions, study of stereochemical asset of catalysis) should be performed to appropriately reveal this “chemical biodiversity” which increases interest for these enzymes. Among other biomolecules, polysaccharides are the most abundant renewable biomaterial found on land and in oceans. Their molecular diversity is very interesting; except polysaccharides used traditionally in food and non-food industries, the structure and the functionality of most of them are unknown and unexplored. Brown seaweeds synthesize unique bioactive polysaccharides: laminarans, alginic acids and fucoidans. A wide range of biological activities (anticoagulant, antitumor, antiviral, anti-inflammation, etc.) have been attributed to fucoidans and their role with respect to structure-activity relationship is still under debate. In this Research Topic, we wish to centralize and review contributions, idea and comments related to the issues above. In particular results of enzymatic bioprospecting in gross marine environment will be acknowledged along with research for structural characterization and biological function of biomolecules such as marine polysaccharides and all kind of research related to the complexity of bioprocesses in marine environments. Inter- and multi-disciplinary approach to this field is favoured in this Research Topic and could greatly be facilitated by the web and open access nature as well.

Enzymes and Their Biotechnological Applications

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ISBN: 9783038421481 9783038421474 Year: Pages: 468 DOI: 10.3390/books978-3-03842-147-4 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Added to DOAB on : 2016-05-12 12:11:22
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Microbial Exopolysaccharides: From Genes to Applications

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198436 Year: Pages: 161 DOI: 10.3389/978-2-88919-843-6 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
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Microbial polysaccharides represent an attractive alternative to those from plants or macro algae. They can be produced from renewable sources including lignocellulosic waste streams. Their production does not depend on geographical constraints and/or seasonal limitations. Additionally the manipulation of biosynthetic pathways to enhance productivity or to influence the chemi-cal polysaccharide composition is comparatively easy in bacteria. Microbial exopolysaccharides represents a valuable resource of biogenic and biodegradable polymers, suitable to replace petro based polymers in various technical applications. Furthermore, biocompatible exopolysaccha-rides are very attractive in medical applications, such as drug delivery systems, use as vaccines or nanoparticles. This research topic will depict the status quo, as well as the future needs in the field of EPS and biofilm research. Starting from the unexplored diversity of microbial polysaccharide producers to production processes and possibilities for modifications, to enhance the already high number of functionalities based on the chemical structures. An overview of the recent and future applications will be given, and the necessity in unravelling the biosynthesis of microbial exopolysaccharide producers is depicted, highlighting the future trend of tailor made polymers. Constraints in structure analysis of these highly complex biogenic polymers are described and different approaches to solve the restrictions in imaging and NMR analysis will be given. Therefore; this research topic comprises the whole process from genes to applications.

Enological Repercussions of Non-Saccharomyces Species

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ISBN: 9783039215584 / 9783039215591 Year: Pages: 218 DOI: 10.3390/books978-3-03921-559-1 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-12-09 11:49:16
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From the beginning of this century, non-Saccharomyces yeasts have taken increased relevance in wine processing. Several biotechnological companies now produce non-Saccharomyces yeasts at an industrial level to improve aroma or flavor, stabilize wine, produce biological acidification, or conversely metabolize malic acid. Species like Torulaspora delbrueckii, Metschnikowia pulcherrima, Kloeckera apiculata, Lachancea thermotolerans, Schizosaccharomyces pombe, and several others are common due to the technological applications they have in sensory quality but also in wine ageing and stabilization. Moreover, spoilage non-Saccharomyces yeasts like Brettanomyces bruxellensis, Saccharomycodes ludwigii, and Zygosacharomyces bailii are becoming important because of the alterations they are able to produce in high-quality wines. New strategies to control these defective yeasts have been developed to control them without affecting sensory quality. The knowledge of the physiology, ecology, biochemistry, and metabolomics of these yeasts can help to better use them in controlling traditional problems such as low fermentative power, excessive volatile acidity, low implantation under enological conditions, and sensibility to antimicrobial compounds like sulfites traditionally used in wine processing. This Special Issue intends to compile current research and revised information on non-Saccharomyces yeasts with enological applications to facilitate the use and the understanding of this biotechnological tool. In 1 year this SI has globally more than 15kdownloads and produced more than 30 citations.

Keywords

Lachancea thermotolerans --- Kluyveromyces thermotolerans --- acidification --- wines --- sequential fermentations --- non-Saccharomyces --- non-Saccharomyces yeasts --- Wickerhamomyces anomalus --- Pichia anomala --- enzymes --- glycosidases --- acetate esters --- biocontrol --- mixed starters --- wine --- wine --- Zygosaccharomyces rouxii --- re-fermentation --- spoilage-control --- non-Saccharomyces --- high-ethanol --- Schizosaccharomyces pombe --- oenological uses --- maloalcoholic fermentation --- stable pigments --- wine safety --- non-Saccharomyces yeast --- Saccharomycodes ludwigii --- S. ludwigii --- spoilage yeasts’ control --- ageing-on-lees --- non-Saccharomyces --- yeast --- sparkling wine --- nitrogen --- aroma --- Candida stellata --- ecology --- taxonomy --- metabolism --- processing foods --- co-fermentation --- non-Saccharomyces --- genome --- aroma compounds --- anthocyanin --- mixed cultures fermentation --- flavor complexity --- Aureobasidium pullulans --- biotechnological applications --- viticulture --- enzymes --- non-Saccharomyces yeasts --- Torulaspora delbrueckii --- winemaking --- yeast inoculation --- yeast dominance --- wine quality --- genetic improvement --- antimicrobial peptides --- biocontrol --- Brettanomyces bruxellensis --- Candida intermedia --- wine --- off-flavors --- wine acidity --- volatile acidity --- malolactic bacteria --- Lactobacillus plantarum --- Lachancea thermotolerans --- Schizosaccharomyces pombe --- Candida stellate --- Torulaspora delbrueckii --- Zygotorulaspora florentina --- Pichia kudriavzevii --- Stermerella bacillaris --- Metschnikowia pulcherrima --- oenological uses --- enzymes --- stable pigments --- pulcherrimin --- n/a --- n/a

Marine Proteins and Peptides

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ISBN: 9783038426462 9783038426479 Year: Pages: 476 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General)
Added to DOAB on : 2018-02-08 13:06:14
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Marine proteins and peptides have great potential application in developing pharmaceuticals, nutraceuticals, and cosmeceuticals. Proteins and peptides from marine sources are considered to be safe and inexpensive. Protein- and peptide-based drugs have been increasing in recent days to cure various diseases by serving multiple roles, such as antioxidants, anticancer drugs, antimicrobials, and anticoagulants. There are different marine sources (macroalgae, fish, shellfish, and bivalves), which possibly contain specific protein and peptides.

Biogenic Amines on Food Safety

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ISBN: 9783039210541 / 9783039210558 Year: Pages: 202 DOI: 10.3390/books978-3-03921-055-8 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-08-28 11:21:27
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Biogenic amines have been known for some time. These compounds are found in varying concentrations in a wide range of foods (fish, cheese, meat, wine, beer, vegetables, etc.) and their formations are influenced by different factors associated to those foods (composition, additives, ingredients, storage, microorganism, packaging, handing, conservation, etc.). The intake of foods containing high concentrations of biogenic amines can present a health hazard. Additionally, they have been used to establish indexes in various foods in order to signal the degree of freshness and/or deterioration of food. Nowadays, there has been an increase in the number of food poisoning episodes in consumers associated with the presence of these biogenic amines, mainly associated with histamines. Food safety is one of the main concerns of the consumer and safety agencies of different countries (EFSA, FDA, FSCJ, etc.), which have, as one of their main objectives, to control these biogenic amines, principally histamine, to assure a high level of food safety.Therefore, it is necessary to deepen our understanding of the formation, monitoring and reduction of biogenic amines during the development, processing and storage of food, even the effect of biogenic amines in consumers after digestion of foods with different levels of these compounds.With this aim, we are preparing a Special Issue on the topic of ""Biogenic Amines in Food Safety"", and we invite researchers to contribute original and unpublished research articles and reviews articles that involve studies of biogenic amines in food, which can provide an update to our knowledge of these compounds and their impacts on food quality and food safety.

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