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Plant responses to flooding

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193042 Year: Pages: 142 DOI: 10.3389/978-2-88919-304-2 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Physiology --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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Global warming has dramatically increased the frequency and severity of flooding events worldwide. As a result, many man-made and natural ecosystems have become flood-prone. For plants, the main consequence of flooding is the drastic reduction of oxygen availability that restricts respiratory energy production and finally affects survival. Flooding can negatively influence crop production and wild plant distributions, since most plants are sensitive to excessively wet conditions. However, plants have evolved a broad spectrum of adaptive responses to oxygen deficiency that eventually leads to tolerance. Many of these morphological and physiological adaptations have been described in some crops and wild plant species and considerable progress has been made in understanding the molecular aspects governing tolerance traits. Moreover, the molecular mechanism of plant oxygen sensing has been recently elucidated. However, many other aspects concerning plant acclimation responses to flooding remain unanswered. With this research topic we seek to build an online collection of articles addressing various aspects relating to “plant responses to flooding’’ which will reflect the exciting new developments and current state of the art in this vibrant and dynamic research field. All kinds of articles, including original research articles, short reviews, methods and opinions are welcome, in the attempt to broadly and freely disseminate research information, tools and protocols.

Keywords

Anoxia --- flooding --- hypoxia --- low oxygen --- submergence --- waterlogging

Targeting Tumor Perfusion and Oxygenation Modulates Hypoxia and Cancer Sensitivity to Radiotherapy and Systemic Therapies (Book chapter)

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ISBN: 9789533077031 Year: DOI: 10.5772/23332 Language: English
Publisher: IntechOpen Grant: FP7 Ideas: European Research Council - 243188
Subject: Science (General)
Added to DOAB on : 2019-01-17 11:47:59
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Hypoxia, a partial pressure of oxygen (pO2) below physiological needs, is a limiting factor affecting the efficiency of radiotherapy. Indeed, the reaction of reactive oxygen species&#xD;&#xD;(ROS, produced by water radiolysis) with DNA is readily reversible unless oxygen stabilizes&#xD;&#xD;the DNA lesion. While normal tissue oxygenation is around 40 mm Hg, both rodent and&#xD;&#xD;human tumors possess regions of tissue oxygenation below 10 mm Hg, at which tumor cells&#xD;&#xD;become increasingly resistant to radiation damage (radiobiological hypoxia) (Gray, 1953).&#xD;&#xD;Because of this so-called “oxygen enhancement effect”, the radiation dose required to&#xD;&#xD;achieve the same biologic effect is about three times higher in the absence of oxygen than in&#xD;&#xD;the presence of normal levels of oxygen (Gray et al., 1953; Horsman & van der Kogel, 2009).&#xD;&#xD;Hypoxic tumor cells, which are therefore more resistant to radiotherapy than well&#xD;&#xD;oxygenated ones, remain clonogenic and contribute to the therapeutic outcome of&#xD;&#xD;fractionated radiotherapy (Rojas et al., 1992).

High-Intensity Exercise in Hypoxia - Beneficial Aspects and Potential Drawbacks

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454068 Year: Pages: 169 DOI: 10.3389/978-2-88945-406-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology
Added to DOAB on : 2018-11-16 17:17:57
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In the past, ‘traditional’ moderate-intensity continuous training (60-75% peak heart rate) was the type of physical activity most frequently recommended for both athletes and clinical populations (cf. American College of Sports Medicine guidelines). However, growing evidence indicates that high-intensity interval training (80-100% peak heart rate) could actually be associated with larger cardiorespiratory fitness and metabolic function benefits and, thereby, physical performance gains for athletes. Similarly, recent data in obese and hypertensive individuals indicate that various mechanisms – further improvement in endothelial function, reductions in sympathetic neural activity, or in arterial stiffness – might be involved in the larger cardiovascular protective effects associated with training at high exercise intensities. Concerning hypoxic training, similar trends have been observed from ‘traditional’ prolonged altitude sojourns (‘Live High Train High’ or ‘Live High Train Low’), which result in increased hemoglobin mass and blood carrying capacity. Recent innovative ‘Live Low Train High’ methods (‘Resistance Training in Hypoxia’ or ‘Repeated Sprint Training in Hypoxia’) have resulted in peripheral adaptations, such as hypertrophy or delay in muscle fatigue. Other interventions inducing peripheral hypoxia, such as vascular occlusion during endurance/resistance training or remote ischemic preconditioning (i.e. succession of ischemia/reperfusion episodes), have been proposed as methods for improving subsequent exercise performance or altitude tolerance (e.g. reduced severity of acute-mountain sickness symptoms). Postulated mechanisms behind these metabolic, neuro-humoral, hemodynamics, and systemic adaptations include stimulation of nitric oxide synthase, increase in anti-oxidant enzymes, and down-regulation of pro-inflammatory cytokines, although the amount of evidence is not yet significant enough. Improved O2 delivery/utilization conferred by hypoxic training interventions might also be effective in preventing and treating cardiovascular diseases, as well as contributing to improve exercise tolerance and health status of patients. For example, in obese subjects, combining exercise with hypoxic exposure enhances the negative energy balance, which further reduces weight and improves cardio-metabolic health. In hypertensive patients, the larger lowering of blood pressure through the endothelial nitric oxide synthase pathway and the associated compensatory vasodilation is taken to reflect the superiority of exercising in hypoxia compared to normoxia. A hypoxic stimulus, in addition to exercise at high vs. moderate intensity, has the potential to further ameliorate various aspects of the vascular function, as observed in healthy populations. This may have clinical implications for the reduction of cardiovascular risks. Key open questions are therefore of interest for patients suffering from chronic vascular or cellular hypoxia (e.g. work-rest or ischemia/reperfusion intermittent pattern; exercise intensity; hypoxic severity and exposure duration; type of hypoxia (normobaric vs. hypobaric); health risks; magnitude and maintenance of the benefits). Outside any potential beneficial effects of exercising in O2-deprived environments, there may also be long-term adverse consequences of chronic intermittent severe hypoxia. Sleep apnea syndrome, for instance, leads to oxidative stress and the production of reactive oxygen species, and ultimately systemic inflammation. Postulated pathophysiological changes associated with intermittent hypoxic exposure include alteration in baroreflex activity, increase in pulmonary arterial pressure and hematocrit, changes in heart structure and function, and an alteration in endothelial-dependent vasodilation in cerebral and muscular arteries. There is a need to explore the combination of exercising in hypoxia and association of hypertension, developmental defects, neuro-pathological and neuro-cognitive deficits, enhanced susceptibility to oxidative injury, and possibly increased myocardial and cerebral infarction in individuals sensitive to hypoxic stress. The aim of this Research Topic is to shed more light on the transcriptional, vascular, hemodynamics, neuro-humoral, and systemic consequences of training at high intensities under various hypoxic conditions.

The regulation of angiogenesis by tissue cell-macrophage interactions

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193172 Year: Pages: 113 DOI: 10.3389/978-2-88919-317-2 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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Angiogenesis is the physiological process where new blood vessels grow from existing ones, in order to replenish tissues suffering from inadequate blood supply. Perhaps the most studied angiogenic process occurs in solid tumors whose growing mass and expanding cells create a constant demand for additional supply of oxygen and nutrients for survival. However, other physiological and clinical conditions, such as wound healing, ischemic events, autoimmune and age-related diseases also involve angiogenesis. Angiogenesis is a well-structured process that begins when oxygen and nutrients are depleted, leading to the release of chemokines and growth factors that attract immune cells, particularly macrophages and endothelial cells to the site. Macrophages that are recruited to the site, as well as tissue cells and endothelial cells, secrete pro-angiogenic mediators that affect endothelial cells and promote angiogenesis. These mediators include growth factors such as vascular endothelial cell growth factor (VEGF), matrix metalloproteinases (MMPs), as well as low levels of mediators that are usually seen as pro-inflammatory but are pro-angiogenic when secreted in low levels (e.g. nitric oxide (NO) and TNFa). Thus, macrophages play a major role in angiogenesis. Macrophages exhibit high plasticity and are capable of shifting between different activation modes and functions according to their changing microenvironment. Small differences in the composition of activating factors (e.g. TLR ligands such as LPS, anti-inflammatory cytokines, ECM molecules) in the microenvironment may differently activate macrophages to yield classically activated macrophages (or M1 macrophages) that can kill pathogen and tumor cells, alternatively activated macrophages (or M2 macrophages) that secrete antiinflammatory cytokines, resolution macrophages (rM?) that are involved in the resolution of inflammation, or regulatory macrophages (e.g. Myeloid-Derived Suppressor Cells - MDSCs) that control the function of other immune cells. In fact, macrophages may be activated in a spectrum of subsets that may differently contribute to angiogenesis, and in particular non-classically activated macrophages such as tumor-associated macrophages (TAMs) and Tie2-expressing monocytes (TEMs) can secrete high amounts of pro-angiogenic factors (e.g. VEGF, MMPs) or low levels of pro-inflammatory mediators (e.g. NO or TNFa) resulting in pro-angiogenic effects. Although the importance of macrophages as major contributors and regulators of the angiogenic process is well documented, less is known about the interactions between macrophages and other cell types (e.g. tumor cells, normal epithelial cells, endothelial cells) that regulate angiogenesis. We still have only limited understanding which proteins or complexes mediate these interactions and whether they require cell-cell contact (e.g. through integrins) or soluble factors (e.g. the EGF-CSF-1 loop), which signaling pathways are triggered in each of the two corresponding cell types, and how this leads to secretion of pro- or antiangiogenic factors in the microenvironment. The regulation of such interactions and through them of angiogenesis, whether through post-translational modifications of proteins or via the involvement of microRNA, is still unclear. The goal of this Research Topic is to highlight these interactions and their regulation in the context of both physiological and pathological conditions.

Tumor Hypoxia: Impact in Tumorigenesis, Diagnosis, Prognosis and Therapeutics

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450640 Year: Pages: 113 DOI: 10.3389/978-2-88945-064-0 Language: English
Publisher: Frontiers Media SA
Subject: Biology --- Science (General) --- Oncology --- Medicine (General)
Added to DOAB on : 2017-07-06 13:27:36
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Hypoxic regions have been identified within tumors and its presence has been linked to malignant progression, metastasis, resistance to therapy, and poor clinical outcomes following treatment. Acute and chronic hypoxia are integral components of tumor microenvironment and conduce to metabolic adaptations of tumor cells leading to genetic instability, intratumor heterogeneity and malignant progression. On the success of our fight against cancer, the continued adaptability of tumors to their microenvironmental stresses, such as hypoxia, must be considered. Tumor cells are endowed with a very high plasticity and capacity to adapt. It is our challenge to find populations and conditions of the tumor microenvironment germane for target success. Interdisciplinary work will be the key for achievement of these goals. This e-book is a compendium of original reports and review articles contributed by world-class experts in the field of tumor hypoxia. This material will be useful to foster discussion and increase understanding of the involvement of hypoxia in tumorigenesis, biomarker development, and therapeutics.Hypoxic regions have been identified within tumors and its presence has been linked to malignant progression, metastasis, resistance to therapy, and poor clinical outcomes following treatment. Acute and chronic hypoxia are integral components of tumor microenvironment and conduce to metabolic adaptations of tumor cells leading to genetic instability, intratumor heterogeneity and malignant progression. On the success of our fight against cancer, the continued adaptability of tumors to their microenvironmental stresses, such as hypoxia, must be considered. Tumor cells are endowed with a very high plasticity and capacity to adapt. It is our challenge to find populations and conditions of the tumor microenvironment germane for target success. Interdisciplinary work will be the key for achievement of these goals. This e-book is a compendium of original reports and review articles contributed by world-class experts in the field of tumor hypoxia. This material will be useful to foster discussion and increase understanding of the involvement of hypoxia in tumorigenesis, biomarker development, and therapeutics.

Keywords

hypoxia --- tumor --- microenvironment --- HIF --- pH --- stress --- Stem Cells --- Leukemia --- biomarkers --- therapy

Self-Eating on Demand: Autophagy in Cancer and Cancer Therapy

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454228 Year: Pages: 111 DOI: 10.3389/978-2-88945-422-8 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Oncology
Added to DOAB on : 2018-11-16 17:17:57
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Macroautophagy, the major lysosomal pathway for recycling intracellular components including whole organelles, has emerged as a key process modulating tumorigenesis, tumor–stroma interactions, and cancer therapy. An impressive number of studies over the past decade have unraveled the plastic role of autophagy during tumor development and dissemination. The discoveries that autophagy may either support or repress neoplastic growth and contextually favor or weaken resistance and impact antitumor immunity have spurred efforts from many laboratories trying to conceptualize the complex role of autophagy in cancer using cellular and preclinical models. This complexity is further accentuated by recent findings highlighting that various autophagy-related genes have roles beyond this catabolic mechanism and interface with oncogenic pathways, other trafficking and degradation mechanisms and the cell death machinery. From a therapeutic perspective, knowledge of how autophagy modulates the tumor microenvironment is crucial to devise autophagy-targeting strategies using smart combination of drugs or anticancer modalities. This eBook contains a collection of reviews by autophagy researchers and provides a background to the state-of-the-art in the field of autophagy in cancer, focusing on various aspects of autophagy regulation ranging from its molecular components to its cell autonomous role, e.g. in cell division and oncogenesis, miRNAs regulation, cross-talk with cell death pathways as well as cell non-autonomous role, e.g. in secretion, interface with tumor stroma and clinical prospects of autophagy-based biomarkers and autophagy modulators in anticancer therapy. This eBook is part of the TransAutophagy initiative to better understand the clinical implications of autophagy in cancer.

Redox and Metabolic Circuits in Cancer

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456352 Year: Pages: 183 DOI: 10.3389/978-2-88945-635-2 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Oncology
Added to DOAB on : 2019-01-23 14:53:43
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Living cells require a constant supply of energy for the orchestration of a variety of biological processes in fluctuating environmental conditions. In heterotrophic organisms, energy mainly derives from the oxidation of carbohydrates and lipids, whose chemical bonds breakdown allows electrons to generate ATP and to provide reducing equivalents needed to restore the antioxidant systems and prevent from damage induced by reactive oxygen and nitric oxide (NO)-derived species (ROS and RNS). Studies of the last two decades have highlighted that cancer cells reprogram the metabolic circuitries in order to sustain their high growth rate, invade other tissues, and escape death. Therefore, this broad metabolic reorganization is mandatory for neoplastic growth, allowing the generation of adequate amounts of ATP and metabolites, as well as the optimization of redox homeostasis in the changeable environmental conditions of the tumor mass. Among these, ROS, as well as NO and RNS, which are produced at high extent in the tumor microenvironment or intracellularly, have been demonstrated acting as positive modulators of cell growth and frequently associated with malignant phenotype. Metabolic changes are also emerging as primary drivers of neoplastic onset and growth, and alterations of mitochondrial metabolism and homeostasis are emerging as pivotal in driving tumorigenesis.Targeting the metabolic rewiring, as well as affecting the balance between production and scavenging of ROS and NO-derived species, which underpin cancer growth, opens the possibility of finding selective and effective anti-neoplastic approaches, and new compounds affecting metabolic and/or redox adaptation of cancer cells are emerging as promising chemotherapeutic tools.In this Research Topic we have elaborated on all these aspects and provided our contribution to this increasingly growing field of research with new results, opinions and general overviews about the extraordinary plasticity of cancer cells to change metabolism and redox homeostasis in order to overcome the adverse conditions and sustain their “individualistic” behavior under a teleonomic viewpoint.

Hypoxia in Kidney Disease

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456178 Year: Pages: 143 DOI: 10.3389/978-2-88945-617-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology
Added to DOAB on : 2019-01-23 14:53:43
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Kidney disease is a complex health problem, often coinciding with cardiovascular pathology (e.g. hypertension) and metabolic disturbances (e.g. obesity and diabetes). It is also a disturbingly fast growing global public health problem, e.g. chronic kidney disease affects an estimated ~9-16% of the population. Besides the public health issues this results in a large economic burden as kidney diseases contributes disproportionally to about a quarter of total health care costs. Experimental and clinical data solidly support the view that kidney tissue hypoxia plays a critical and intricate role during the genesis and progression of both chronic and acute kidney diseases. This research field is currently at the very beginning of integrating pre-clinical with clinical research in which hypoxia related mechanism are quantified by non-invasive imaging. In combination with the fact that some key questions remain unanswered, this offers exciting new research perspectives that are waiting to be explored. With this Research Topic we aim to discuss and find answers to the following research question: 1) What are the temporal relationships between hypoxia and kidney disease? 2) Can we demonstration causation between hypoxia and kidney disease? 3) Can renal hypoxia be considered as a treatment target in kidney disease? 4) Can hypoxia (e.g. in the urine) be considered a biomarker of kidney disease? 5) Does hypoxia ramp-up sympathetic activity? 6) Does hypoxia trigger inflammation? 7) Is hypoxia caused by changes in sodium reabsorption and/or mitochondrial function? 8) Which molecular mechanisms are involved in hypoxia in kidney disease? 9) Which gene expressions change due to hypoxia in kidney disease? 10) Can we generate new and translational insights using non-invasive imaging technologies? Our overall aim is identify the mediators/controllers of hypoxia in kidney disease. If we understand more about the sequence of events leading to hypoxia, its regulation and consequences in renal disease, we might be able to have a major impact in clinical practice. I.e. more accurate and earlier diagnosis, novel treatment targets, and novel therapies.

Cell Stress, Metabolic Reprogramming, and Cancer

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455652 Year: Pages: 68 DOI: 10.3389/978-2-88945-565-2 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Oncology
Added to DOAB on : 2019-01-23 14:53:43
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The present eBook presents one review, five mini-reviews, and an opinion article on the achievements and perspectives of studies on important aspects of cancer cell metabolic reprogramming whose mechanisms and regulation are still largely elusive. It also sheds light on certain novel functional components, which rewires cell metabolism in tumor transformation.

Pleiotropic Action of Selenium in the Prevention and Treatment of Cancer, and Related Diseases

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ISBN: 9783038976929 Year: Pages: 166 DOI: 10.3390/books978-3-03897-693-6 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology --- Science (General)
Added to DOAB on : 2019-04-05 11:07:22
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This book will cover topics related to the preparation and use of heterogeneous catalytic systems for the transformation of renewable sources, as well as of materials deriving from agro-industrial wastes and by-products. At the same time, the ever-increasing importance of bioproducts, due to the acceptance and request of consumers, makes the upgrade of biomass into chemicals and materials not only an environmental issue, but also an economical advantage.

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