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Functional and Bioactive Properties of Food

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ISBN: 9783038973546 9783038973553 Pages: 174 DOI: 10.3390/books978-3-03897-355-3 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Nutrition and Food Sciences --- Biology
Added to DOAB on : 2018-11-23 11:11:39
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Diet and nutrition are key tools in promoting health and reducing the comorbidities of chronic diseases. There are thousands of biomolecules in fruits, vegetables, wild and medicinal plants, other land and marine organisms, which can exert functional and health-promoting effects through bioactivity beyond nutrition. From the enormous amount of knowledge generated from different natural bioactive ingredients present in foods, we are aiming to bring together experts working in different fields of food, nutrition, and health, in order to work on this Special Issue, with a comprehensive collection of papers to gain insight into the most promising bioactive compounds in different foods, to improve the preservation of bioactivity during the food processing chain, and to provide scientific evidence of the efficacy of key bioactives in foods in preventing disease and improving health and wellbeing.

Metabolic Adaptation to Cell Growth and Proliferation in Normal and Pathological Conditions

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454846 Year: Pages: 70 DOI: 10.3389/978-2-88945-484-6 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Internal medicine
Added to DOAB on : 2019-01-23 14:53:42
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Proliferating cells must adapt their metabolism to fulfill the increased requirements for energy demands and biosynthetic intermediates. This adaptation is particularly relevant in cancer, where sustained rapid proliferation combined with the harsh conditions of the tumor microenvironment represent a major metabolic challenge. Noteworthy, metabolic reprogramming is now considered one of the hallmarks of cancer. However, the one size fits all rarely applies to the metabolic rewiring occurring in cancer cells, which ultimately depends on the combination of several factors such as the tumor’s origin, the specific genetic alterations and the surrounding microenvironment. In the present Research Topic, we compile a series of articles that discuss different metabolic adaptations that proliferating cells undergo to sustain growth and division, as well as the potential therapeutic window to treat certain pathologies, with a special focus on cancer.

Metabolism and Immune Tolerance

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889457250 Year: Pages: 116 DOI: 10.3389/978-2-88945-725-0 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2019-01-23 14:53:43
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Historically the study of the immune system and metabolism have been two very separate fields. In recent years, a growing literature has emerged illustrating how the multiple processes of cellular metabolism are intricately linked to several aspects of immune function and development. This Research Topic covers recent progress in the field now known as “Immunometabolism” and the role of metabolism in immune tolerance. Immune tolerance is operationally defined as a state where a host’s immune system is balanced such that although self-reactive lymphocytes are present, they are kept in check by immune regulation. Perturbations to this homeostasis may result in self-reactive lymphocytes gaining the upper hand and mediating auto-immune disease. Maintenance of immune tolerance involves a large cast of different cell types including effector T cells, regulatory T cells, B cells, stromal cells, dendritic cells and macrophages.Intracellular pathways and individual enzymes of metabolism have been shown to be harnessed by cells of both the adaptive and innate immune system to allow particular immune functions to be achieved. Examples include metabolic enzymes serving ‘moonlighting’ functions in mRNA translation, gene splicing, and kinase activation. Other examples include the requirement for de novo fatty acid synthesis for differentiation into Th17 effectors and CD8 memory T cells or products of the TCA cycle promoting pro-inflammatory cytokine production. Likewise, the availability of extracellular metabolic substrates has a large impact on the maintenance of local immune tolerance. For example, there are different requirements for glucose, glutamine and fatty acids for effector versus regulatory T cell development. Also tolerogenic dendritic cells mediate lowering of extracellular essential amino acids by their enhanced catabolism, promoting the induction of regulatory T cells. The purpose of this Research Topic is to provide an update on the current understanding of the multiple roles for metabolism in regulating the immune system.

Synthetic Biology: Engineering complexity and refactoring cell capabilities

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196852 Year: Pages: 123 DOI: 10.3389/978-2-88919-685-2 Language: English
Publisher: Frontiers Media SA
Subject: Biotechnology --- General and Civil Engineering
Added to DOAB on : 2015-10-30 16:33:44
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One of the key features of biological systems is complexity, where the behavior of high level structures is more than the sum of the direct interactions between single components. Synthetic Biologists aim to use rational design to build new systems that do not already exist in nature and that exhibit useful biological functions with different levels of complexity. One such case is metabolic engineering, where, with the advent of genetic and protein engineering, by supplying cells with chemically synthesized non-natural amino acids and sugars as new building blocks, it is now becoming feasible to introduce novel physical and chemical functions and properties into biological entities. The rules of how complex behaviors arise, however, are not yet well understood. For instance, instead of considering cells as inert chassis in which synthetic devices could be easily operated to impart new functions, the presence of these systems may impact cell physiology with reported effects on transcription, translation, metabolic fitness and optimal resource allocation. The result of these changes in the chassis may be failure of the synthetic device, unexpected or reduced device behavior, or perhaps a more permissive environment in which the synthetic device is allowed to function. While new efforts have already been made to increase standardization and characterization of biological components in order to have well known parts as building blocks for the construction of more complex devices, also new strategies are emerging to better understand the biological dynamics underlying the phenomena we observe. For example, it has been shown that the features of single biological components [i.e. promoter strength, ribosome binding affinity, etc] change depending on the context where the sequences are allocated. Thus, new technical approaches have been adopted to preserve single components activity, as genomic insulation or the utilization of prediction algorithms able to take biological context into account. There have been noteworthy advances for synthetic biology in clinical technologies, biofuel production, and pharmaceuticals production; also, metabolic engineering combined with microbial selection/adaptation and fermentation processes allowed to make remarkable progress towards bio-products formation such as bioethanol, succinate, malate and, more interestingly, heterologous products or even non-natural metabolites. However, despite the many progresses, it is still clear that ad hoc trial and error predominates over purely bottom-up, rational design approaches in the synthetic biology community. In this scenario, modelling approaches are often used as a descriptive tool rather than for the prediction of complex behaviors. The initial confidence on a pure reductionist approach to the biological world has left space to a new and deeper investigation of the complexity of biological processes to gain new insights and broaden the categories of synthetic biology. In this Research Topic we host contributions that explore and address two areas of Synthetic Biology at the intersection between rational design and natural complexity: (1) the impact of synthetic devices on the host cell, or "chassis" and (2) the impact of context on the synthetic devices. Particular attention will be given to the application of these principles to the rewiring of cell metabolism in a bottom-up fashion to produce non-natural metabolites or chemicals that should eventually serve as a substitute for petrol-derived chemicals, and, on a long-term view, to provide economical, ecological and ethical solutions to today’s energetic and societal challenges.

Mitochondria: the cell powerhouse and nexus of stress

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192830 Year: Pages: 121 DOI: 10.3389/978-2-88919-283-0 Language: English
Publisher: Frontiers Media SA
Subject: Biology --- Physiology --- Science (General)
Added to DOAB on : 2015-12-10 11:59:06
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Mitochondrion, a sub-cellular organelle originated from primary endosymbiosis, plays a vital role in energy metabolism of eukaryotic cells. The transfer of electrons through the electron transport chain (ETC) to molecular oxygen accompanied by the extrusion of protons from the matrix generate an electrochemical gradient across the inner mitochondrial membrane (IMM) that is used for ATP synthesis by oxidative phosphorylation. Despite many aspects of ATP synthesis have been delineated, regulatory mechanisms responsible for energy synthesis and transfer still remain to be uncovered. In addition to energy function, mitochondria play a crucial role in cell metabolism under both physiological and pathological conditions through their participation in many intracellular signaling pathways. Studies over the last 30 years provide strong evidence that mitochondria are the nexus of various stresses which initiate cell death through apoptosis, oncosis, necrosis and autophagy depending on the severity of the stress and cellular energy status. The release of several pro-apoptotic proteins such as cytochrome c, Smac/DIABLO, AIF, endonuclease G from intermembrane space initiates both caspase-dependent and caspase-independent apoptosis. The formation of the mitochondrial permeability transition pore in the IMM promotes cell death mostly through necrosis whereas a mild stress activates autophagy. Due to their critical roles in both cell death and survival mitochondria have been widely considered as an important target for various pharmacological and conditional therapeutic approaches. Currently, a large number of mitochondria-targeted agents are suggested to prevent (in ischemia reperfusion injury, cardiovascular, neurodegenerative and other diseases) or stimulate (in various cancers) cell death. This Research Topic focuses on the role of mitochondria in the regulation of cell metabolism and signaling under physiological and pathological conditions. Studies performed on cultured cells and isolated organs/tissues using different animal and cellular models of various diseases are also included and discussed.

CD4+ T cell differentiation in infection: amendments to the Th1/Th2 axiom

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195657 Year: Pages: 111 DOI: 10.3389/978-2-88919-565-7 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-01-19 14:05:46
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CD4+ T lymphocytes play an essential role in host defense against bacterial, parasitic and viral infections. During infection, under the influence of intrinsic signals received through peptide-MHC/TCR interactions and extrinsic signals provided by pathogen-conditioned dendritic and other accessory cells, CD4+ T cells proliferate and differentiate into specialized T helper (Th) effectors, which produce distinct sets of cytokines tailored to combat a specific class of microbes. The concept of CD4+ T cell multi-functionality was developed after the seminal discovery of Th1 and Th2 cells nearly 30 years ago. Although the Th1/Th2 paradigm has successfully withstood the test of time, in the past decade additional Th subsets (Th17, Tfh, Th22, Th9) have been identified. Similarly, single cell analyses of cytokines and master transcriptional factors have revealed that, at the population level, CD4+ T cell responses are far more heterogeneous than initially anticipated. While some of the checkpoints in Th cell specification have been identified, recent studies of transcriptional and epigenetic regulation have uncovered a significant flexibility during the course CD4+ T lymphocyte polarization. In addition, Th cells expressing cytokines with counteracting functions, as a measure of self-regulation, display yet another level of diversity. Understanding the mechanisms that control the balance between stability vs. plasticity of Th effectors both at the time of initiation of immune response and during development of CD4 T cell memory is critical for the rational design of better vaccines and new immunotherapeutic strategies. This research topic will cover current views on Th cell development, with a focus on the mechanisms that govern differentiation, function and regulation of effector Th cells in the context of microbial infections.

Molecular Regulation and Therapeutic Potential of Thermogenic Fat Cells

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198696 Year: Pages: 127 DOI: 10.3389/978-2-88919-869-6 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General)
Added to DOAB on : 2016-01-19 14:05:46
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Obesity has emerged as a major threat to public health in both the western and developing world. Essentially a disorder of energy balance, obesity occurs when energy intake and storage exceeds expenditure. Much of energy homeostasis depends on the activity and function of adipose tissue. Adipocytes in mammals fall into two categories classified by their primary functions: white fat cells that mediate energy storage and thermogenic fat cells that counteract hypothermia and obesity through adaptive thermogenesis. Whereas white fat and its function as an energy reservoir and endocrine organ have been studied for decades and are relatively well understood, until recently many aspects of the thermogenic fat biology have remained elusive. Accumulating evidence supports the hypothesis that thermogenic fat cells arise from at least two different developmental origins: the ones of a skeletal muscle-like lineage are now called “classical” brown fat cells, and the rest of the thermogenic fat cells are normally referred to as the beige fat cells. The last decade has witnessed an explosion of interest and studies focusing on the regulation of thermogenic fat cells and potential therapeutics targeting these adipocytes. Here we summarize the recent advancements in our understanding of these metabolically active fat cells.

Proceedings of the 3rd International Conference on Genetics of Aging and Longevity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199266 Year: Pages: 88 DOI: 10.3389/978-2-88919-926-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Genetics
Added to DOAB on : 2016-01-19 14:05:46
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In this book, we present a collection of articles covering a wide range of current aging research and highlighting its prospects and future directions. These articles are based on or related to the topics of the 3rd International Conference «Genetics of aging and longevity». The Conference took place 6-10 April, 2014 in Sochi, the city located on the Black Sea coast near the Caucasian mountains, in Russia. Top gerontologists and geneticists from 31 countries around the world came together to discuss current problems in many areas related to the genetics of longevity and mechanisms of aging. We would like to thank those of them who contributed to this e-Book by sharing latest achievements, ideas and hypotheses. We hope that this e-Book will come to notice of scientists interested in the development of genetics of aging and longevity and in the search for life-beneficial environments and life-prolonging interventions.

The Coming of Age of Insulin-Signalling in Insects

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193141 Year: Pages: 138 DOI: 10.3389/978-2-88919-314-1 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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The new millennium has seen a major paradigm shift in insect endocrinology. Great advancements are being made which establish that nutrition and growth play a central role in diverse cellular and physiological phenomena during insect development and reproduction. Nutrition affects rates of growth and is mainly regulated by the function of the pathway of insulin/insulin-like growth factor signalling. This pathway is highly conserved across species and ultimately regulates rates of cell growth and proliferation in growing organs. Insulin and insulin-like peptides (ILPs) are some of the best studied hormones in the animal kingdom and all share a common structural motif and initiate a wide range of closely similar physiological processes in higher organisms. In insects, nutrition, via circulating sugar, promotes release of ILPs from brain neurosecretory cells into the haemolymph, which act on peripheral tissues and stimulate protein synthesis and cell growth. Therefore, insect ILPs are common mediators between nutrition and growth in insects and are functionally analogous to mammalian insulin. The 1980s and 1990s witnessed great progress in elucidation of the physiological and molecular mechanism of action of numerous insect hormones involved in regulation of growth, development, reproduction and metabolism. But the signals for the initiation or termination of controlled events remained largely unknown. ILPs were first identified from the silkmoth Bombyx mori and were named bombyxins, but related peptides were soon found in numerous species and their functions elucidated. The insulin signalling pathway is now recognized as a central factor in the timing of cell proliferation, growth, longevity, reproduction, and reproductive diapause, as well as social behaviour. Recent work has revealed that the insulin signalling pathway is closely integrated with that of various other hormones, including ecdysteroids, the juvenile hormones and neuropeptide(s) such a prothoracicotropic hormone. In addition, the pathway is also linked with both circadian (daily) and photoperiodic (seasonal) clocks potentially providing a basis for its timing function. This Research Topic aims to provide the only current collection of recent advances on insect ILPs. We encouraged submissions on all areas related to identification, characterization, regulation and physiological functions of insect ILPs. We welcomed both full and short reviews and original research articles.

Glycolysis at 75: Is it time to tweak the first elucidated metabolic pathway in history?

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195862 Year: Pages: 126 DOI: 10.3389/978-2-88919-586-2 Language: English
Publisher: Frontiers Media SA
Subject: Nutrition and Food Sciences --- Medicine (General) --- Neurology --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
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Glycolysis, the pathway of enzymatic reactions responsible for the breakdown of glucose into two trioses and further into pyruvate or lactate, was elucidated in 1940. For more than seven decades, it has been taught precisely the way its sequence was proposed by Embden, Meyerhof and Parnas. Accordingly, two outcomes of this pathway were proposed, an aerobic glycolysis, with pyruvate as its final product, and an anaerobic glycolysis, identical to the aerobic one, except for an additional reaction, where pyruvate is reduced to lactate. Several studies in the 1980s have shown that both muscle and brain tissues can oxidize and utilize lactate as an energy substrate, challenging this monocarboxylate’s reputation as a useless end-product of anaerobic glycolysis. These findings were met with great skepticism about the idea that lactate could be playing a role in bioenergetics. In the past quarter of a century monocarboxylate transporters (MCTs) were identified and localized in both cellular and mitochondrial membranes. A lactate receptor has been identified. Direct and indirect evidence now indicate that the enzyme lactate dehydrogenase (LDH) resides not only in the cytosol, as part of the glycolytic pathway machinery, but also in the mitochondrial outer membrane. The mitochondrial form of the enzyme oxidizes lactate to pyruvate and concomitantly produces the reducing agent NADH. These findings have shed light on a major drawback of the originally proposed aerobic version of the glycolytic pathway i.e., its inability to regenerate NAD+, as opposed to anaerobic glycolysis that features the cyclical ability of regenerating NAD+ upon pyruvate reduction to lactate by the cytosolic form of LDH. The malate-aspartate shuttle (MAS), a major redox shuttle in the brain, was proposed as an alternative pathway for NAD+ generation for aerobic glycolysis. Nonetheless, would MAS really be necessary for that function if glycolysis always proceeds to the end-products, lactate and NAD+? An additional dilemma the originally proposed aerobic glycolysis presents has to do with the glycolytic pathway of erythrocytes, which despite its highly aerobic environment, always produces lactate as its end-product. It is time to reexamine the original, dogmatic separation of glycolysis into two distinct pathways and put to test the hypothesis of a unified, singular pathway, the end-product of which is lactate, the real substrate of the mitochondrial TCA cycle.

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