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The Roles of GnIH in Reproductive Function and Behavior

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454426 Year: Pages: 128 DOI: 10.3389/978-2-88945-442-6 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Internal medicine
Added to DOAB on : 2018-11-16 17:17:57
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Since the discovery of gonadotropin-releasing hormone (GnRH) at the beginning of 1970s, it has been believed that GnRH is the only hypothalamic neuropeptide that regulates gonadotropin release in vertebrates. In 2000, however, a novel hypothalamic neuropeptide that actively inhibits gonadotropin release was discovered in Japanese quail and termed gonadotropin-inhibitory hormone (GnIH). Following seventeen years of research has revealed that GnIH is highly conserved across vertebrates including humans, and GnIH is involved in a number of physiological and behavioral functions related to reproduction. The aim of this e-book is to celebrate the discovery of GnIH and the progress of GnIH research by collecting review and original articles from leading scientists in this new research field.

The Natriuretic Hormones

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197095 Year: Pages: 76 DOI: 10.3389/978-2-88919-709-5 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General)
Added to DOAB on : 2016-04-07 11:22:02
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The title follows from the original demonstration by Dr. Hugh de Wardener in 1961 that a humoral agent is produced after extracellular volume expansion which results in a vigorous diuresis and natriuresis. Thus the name of "natriuretic hormone" was coined. In the years that followed several investigators pursued the search for the hormone. What resulted, however, was the discovery of several hormones with different characteristics, all of which were natriuretic. Initially it was found that the hormone was similar in action to ouabain or digoxin, hence the appelation of ouabain-like or digoxin-like. The hormone was found to be an inhibitor of Na-K-ATPase, which would fit with it being a cardiotonic steroid. On the other hand, neither ouabain or digoxin migrated on Sephadex gel filtration in the same locus as the hormone. Other investigators claim to have identified the hormone-initially as a vanadium-diascorbate, later as bufadienolides such as marinobufagenin, yet later as a macrocylic derivative of inorganic carbon suboxide with a molecular weight of 408 Da. Some support for the latter finding was derived from an earlier report that a semi-purified Sephadex-derived compound was found to have a molecular weight of about 12,000 Da but the active compound, when split from its carrier protein, had a molecular weight of exactly 408 Da. This compound had not been further identified. As further development was the demonstration by Bricker and colleagues that a natriuretic substance could be purified from uremic urine. This turned out to be a xathurenic acid derivative. Meanwhile the focus began to turn to natriuretic peptides derived from heart (ANF and BNP). These peptides have a shorter duration of action than the cardiotonic steroid-like hormone and ANF has proved to be most useful as a measure of heart failure. It should also be stressed that marinobufagenin, like ANF, is elevated in congestive heart failure, whereas the steroid-like hormone is depressed or absent in this state. This review will attempt to describe and contrast the properties of each of the proposed natriuretic hormones, including their locus on Sephadex separation, potency, duration of action, chemical structure (if known), behavior in hypertension, renal failure, heart failure, and brain disease. As most recent work has focussed on marinobufagenin, this hormone will be brought up to date by investigators in the field.

Thyroid hormone in brain and brain cells

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197026 Year: Pages: 106 DOI: 10.3389/978-2-88919-702-6 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General)
Added to DOAB on : 2016-04-07 11:22:02
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Thyroid hormone signaling has been known for a long time to be required for proper neurodevelopment and the maintenance of cognitive functions in the adult brain. As thyroid hormone excess or deficiency is usually well handled by clinicians, research dedicated to the neural function of thyroid hormone, have not been a priority within the field. This is changing mainly for two reasons. First, new genetic diseases have been discovered, altering thyroid hormone signaling in brain (THRA, MCT8, SBP2), with neurodevelopmental consequences which are currently incurable. Second, there is a growing concern that exposition of the general population to environmental chemicals able to interfere with thyroid hormone signaling compromises children neurodevelopment or induces central disorders in adults. Finally thyroid hormone is acting directly on gene transcription, by binding nuclear receptors, and therefore is an interesting entry point to identify genetic programs controlling brain development and function. Reaching a broad understanding of the multiple processes involving thyroid hormone in brain is a tremendous task which will necessitate a multidisciplinary approach: animal genetics, molecular biology, brain imaging, developmental biology, genomics, etc... This topic will be the occasion to combine recent contributions in the field and to identify priorities for future investigations. Due to devastating consequences of congenital hypothyroidism, the neurodevelopmental consequences of altered thyroid hormone signaling have been extensively studied over the years. The discovery of new genetic diseases, the concern about the possible neurotoxicity of environmental thyroid hormone disruptors, recently renewed the interest for an important research field. This Ebook gathers reviews and original data from experts in various disciplines. It provides a broad view of ongoing research and outlines key issues for future investigation.

ROS Regulation during Plant Abiotic Stress Responses

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450541 Year: Pages: 306 DOI: 10.3389/978-2-88945-054-1 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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Plants are continuously exposed to a wide range of environmental conditions, including cold, drought, salt, heat, which have major impact on plant growth and development. To survive, plants have evolved complex physiological and biochemical adaptations to cope with a variety of adverse environmental stresses. Among them, reactive oxygen species (ROS) are key regulators and play pivotal roles during plant stress responses, which are thought to function as early signals during plant abiotic stress responses. ROS were long regarded as unwanted and toxic by-products of physiological metabolism. However, ROS are now recognized as central players in the complex signaling network of cells. Therefore, a fine-tuning control between ROS production and scavenging pathways is essential to maintain non-toxic levels in planta under stressful conditions through enzymatic and non-enzymatic antioxidant defense systems. We focus on the roles of ROS during plant abiotic stress responses in this Research Topic. Plant responses to multiple abiotic stresses and effects of hormones and chemicals on plant stress responses have been carefully studies. Although functions of several stress responsive genes have been characterized and possible interactions between hormones and ROS are discussed, future researches are needed to functionally characterize ROS regulatory and signaling transduction pathways.Plants are continuously exposed to a wide range of environmental conditions, including cold, drought, salt, heat, which have major impact on plant growth and development. To survive, plants have evolved complex physiological and biochemical adaptations to cope with a variety of adverse environmental stresses. Among them, reactive oxygen species (ROS) are key regulators and play pivotal roles during plant stress responses, which are thought to function as early signals during plant abiotic stress responses. ROS were long regarded as unwanted and toxic by-products of physiological metabolism. However, ROS are now recognized as central players in the complex signaling network of cells. Therefore, a fine-tuning control between ROS production and scavenging pathways is essential to maintain non-toxic levels in planta under stressful conditions through enzymatic and non-enzymatic antioxidant defense systems. We focus on the roles of ROS during plant abiotic stress responses in this Research Topic. Plant responses to multiple abiotic stresses and effects of hormones and chemicals on plant stress responses have been carefully studies. Although functions of several stress responsive genes have been characterized and possible interactions between hormones and ROS are discussed, future researches are needed to functionally characterize ROS regulatory and signaling transduction pathways.

"One rotten apple spoils the whole barrel": The plant hormone ethylene, the small molecule and its complexity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196234 Year: Pages: 132 DOI: 10.3389/978-2-88919-623-4 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-08-16 10:34:25
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The gaseous molecule ethylene (C2H4), which is small in size and simple in structure, is a plant hormone most often associated with fruit ripening yet has a diversity of effects throughout the plant life cycle. While its agricultural effects were known even in ancient Egypt, the complexity of its mode of action and the broad spectrum of its effects and potential uses in plant physiology remain important scientific challenges today. In the last few decades, the biochemical pathway of ethylene production has been uncovered, ethylene perception and signaling have been molecularly dissected, ethylene-responsive transcription factors have been identified and numerous effects of ethylene have been described, ranging from water stress, development, senescence, reproduction plant-pathogen interactions, and of course, ripening. Thus ethylene is involved in plant development, in biotic and abiotic stress, and in reproduction. There is no stage in plant life that is not affected by ethylene, modulated by a complex and fascinating molecular machinery.

Parasites in the Tropic - A New Paradigm Shift

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452088 Year: Pages: 84 DOI: 10.3389/978-2-88945-208-8 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General) --- Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2017-10-13 14:57:01
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The highlight of this eBook is to bring new insights into parasites in the tropic. To achieve that, much has been discussed about risk assessment, infection rates, disease burden, hormones and mechanism of immune response, genetic expression and susceptibility as well as, therapeutic modalities. Authors raised hypothesis, discuss concepts, and show open questions. The remaining important issues to resolve questions within parasites in the tropic – a new paradigm shift are briefly discussed below. T. gondii, feline as the definitive host, is regarded as one of the most important parasites in the tropic. Human, as an accidental host, is the only species who still drinks raw milk or milk products particularly from animal sources. Based on the first paper, the author simplifies on how safe to drink milk to prevent the transmission of T. gondii by the insistence on heat treated milk before consumption. It is interesting to explore how hormone plays its role in Toxoplasma infection. Based on the second paper, the authors elucidated from thirty studies from humans, animals and cell cultures. Of these, it was shown that Toxoplasma infection was controlled by the presence of hormones found in different animal models. However, it is still premature to conclude which hormone that has a significant relationship with Toxoplasma infection. It estimates that one-third of the world population infected with T. gondii but the majority are asymptomatic. Based on the third paper, it demonstrated that people having low prevalent of Toxoplasma infection by having close contact with animals. This study will enhance positive attitudes for more people to be committed towards helping animals. For more than three decades, T. gondii has since been identified as one of the most important opportunistic parasitic pathogens in immunocompromised. Seroprevalence of chronic toxoplasmosis was detected in at least one-third of HIV-infected individuals in the regional hospital of southern Thailand, as reported from the fourth paper. Thailand has successfully formulated anti-retroviral therapy for HIV/AIDS patients and as a result reported a rare incidence of AIDS-related cerebral toxoplasmosis (CT) in this setting. Based on the fifth paper, the authors demonstrated low IL-10 (Th2 response) and IFN-γ (Th1 response) as well as high TNF-α were produced in ocular and cerebral toxoplasmosis in AIDS patients. This might be due to South American strains and/or the genetic susceptibility of the host.Due to high genetic diversity of T. gondii in Brazil, the sixth paper demonstrated that Calomys callosus survived chronically infected by T. gondii clonal type II strain and reinfected by Brazilian strains. However, congenital toxoplasmosis occurred leading to damaging effects of the developing fetus. The seventh paper conducted a questionnaire-based study on knowledge and practice on Toxoplasma infection among pregnant women from Malaysia, Philippines and Thailand. It clearly demonstrated that health education, a core value, is the cheapest and the best option to envisage the preventive strategies of feto-maternal toxoplasmosis from this region. For treatment modality of congenital toxoplasmosis, a novel experimental therapeutic synergism of diclazuril plus atovaquone combination shows a promising outcome with no toxicity in treating this condition, as demonstrated in the eighth paper. However, it warrants for future trials to prove its properties against T. gondii in different clinical scenarios of human toxoplasmosis for more effective therapeutic regimens. In the ninth paper, the author discussed the pathogenesis of maternal and congenital toxoplasmosis, the current treatment in clinical practice, and the experimental treatment approaches for promising future trials. Overall, this protozoan represents the most extraordinary example of parasite in the tropic and beyond scientific imagination. Hence, there are still many challenges ahead and waiting for more explorations on T. gondii, the parasite that never dies. Based on the findings from the tenth paper, it is interesting to identify common gene targets between Glossina p. gambiensis and Glossina m. morsitans that might shed some lights as a suitable candidate for controlling both acute and chronic forms of sleeping sickness. This therefore requires further investigations using proteomic analysis to ascertain the corresponding genes and its proteins as well as functional role that may help the search for more novel therapeutic agents.

Plant immunity against viruses

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452699 Year: Pages: 163 DOI: 10.3389/978-2-88945-269-9 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology
Added to DOAB on : 2018-02-27 16:16:44
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Plant viruses impose a serious threat on agriculture, which motivates extensive breeding efforts for viral resistant crops and inspires lasting interests on basic research to understand the mechanisms underlying plant immunity against viruses. Viruses are obligate intracellular parasites. Their genomes are usually small and only encode a few products that are essential to hijack host machinery for their nucleotide and protein biosynthesis, and that are necessary to suppress host immunity. Plants evolved multilayers of defense mechanisms to defeat viral infection. In this research topic, we gathered 13 papers covering recent advances in different aspects of plant immunity against viruses, including reviews on RNA silencing and R gene based immunity and their application, translational initiation factor mediated recessive resistance, genome editing based viral immunity, role of chloroplast in plant-virus interaction, and research articles providing new mechanistic insights on plant-virus interactions. We hope that this Research Topic helps readers to have a better understanding of the progresses that have been made recently in plant immunity against viruses. A deeper understanding of plant antiviral immunity will facilitate the development of innovative approaches for crop protections and improvements.

Molecular Biology of Bamboo mosaic Virus - A Type Member of the Potexvirus Genus

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454396 Year: Pages: 109 DOI: 10.3389/978-2-88945-439-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology --- Botany
Added to DOAB on : 2018-11-16 17:17:57
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The flexible filamentous plant viruses are responsible for more than half of all agricultural loss worldwide. Potexvirus is one of the two most important flexible filamentous plant viruses. Bamboo mosaic virus (BaMV), a single-stranded positive-sense RNA virus, is a member of the Potexvirus genus of Alphaflexiviridae. It can infect at least 12 species of bamboo, causing a huge economic impact on the bamboo industry in Taiwan. The study of BaMV did not start extensively until the completion of the full-length sequencing of genomic RNA of BaMV and generation of the BaMV infectious cDNA clone in the early 1990s. Since then, BaMV has been extensively studied at the molecular, cellular and ecological level, covering both basic and applied researches, by a group of researchers in Taiwan. In this eBook, the content comprises 6 reviews and 4 articles. Seven of them are involved in the infection of BaMV covering viral RNA replication, viral RNA trafficking, and the host factors. Two of them are related to the vector transmission and the ecology of BaMV. The last one is the application of using BaMV as a viral vector to produce vaccines in plants.

Physiology and Pathophysiology of the Extracellular Calcium-Sensing Receptor

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455126 Year: Pages: 189 DOI: 10.3389/978-2-88945-512-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology
Added to DOAB on : 2019-01-23 14:53:42
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Calcium is vital for human physiology; it mediates multiple signaling cascades, critical for cell survival, differentiation, or death both as first and as second messenger. The role of calcium as first messenger is mediated by the G-protein coupled receptor, the extracellular calcium-sensing receptor (CaSR). The CaSR is a multifaceted molecule that senses changes in the concentration of a wide variety of environmental factors including di- and trivalent cations, amino acids, polyamines, and pH. In calcitropic tissues with obvious roles in calcium homeostasis such as parathyroid, kidney, and bone it regulates circulating calcium concentrations. The germline mutations of the CaSR cause parathyroid disorders demonstrating the importance of the CaSR for the maintenance of serum calcium homeostasis. The CaSR has an important role also in a range of non-calcitropic tissues, such as the intestine, lungs, central and peripheral nervous system, breast, skin and reproductive system, where it regulates molecular and cellular processes such as gene expression, proliferation, differentiation and apoptosis; as well as regulating hormone secretion and lactation.This Research Topic is an overview of the CaSR and its molecular signaling properties together with the various organ systems where it plays an important role. The articles highlight the current knowledge regarding many aspects of the calcitropic and non-calcitropic physiology and pathophysiology of the CaSR.

Chemical Biology of Sterols, Triterpenoids and Other Natural Products: A Themed Issue in Honor of Professor W. David Nes on the Occasion of His 65th Birthday

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ISBN: 9783038974161 / 9783038974178 Year: Pages: 256 DOI: 10.3390/books978-3-03897-417-8 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Biochemistry
Added to DOAB on : 2019-06-26 08:44:06
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Sterols and other isoprenoids are of great interest for their molecular structure and function in cell architecture and evolution, as well as for their importance in medicine and agriculture. Molecules’ 2019 Festschrift Special Issue in honor of the 65th birthday of Prof. W. David Nes, an internationally recognized chemical biologist and recipient of the George Schroepher medal for sterol research, focuses on recent developments in the chemistry, biosynthesis, and function of these polycyclic natural products. This volume of Molecules contains 16 leading-edge review articles and original research contributions from an international cast of scientists. This volume is grouped into three sections: (i) isoprenoid metabolome and diversity, (ii) clinical evaluation of sterol and triterpene structures and biosynthesis, and (iii) methods and synthesis of steroids and other compounds. The volume will be a valuable reference tool for those who study medicinal chemistry, protein chemistry, and biochemistry of isoprenoid lipids.

Keywords

Zingiber officinale --- gingerols --- cytotoxic activity --- oleanolic acid --- high-fat high-carbohydrate diet --- pre-diabetes --- glucose homeostasis --- insulin resistance --- atherosclerosis --- ROS --- HUVECs --- LOX-1 --- alkaloid --- granatane --- N-methylcadaverine --- N-methylpiperidine. reductive deamination --- Mucorales --- Rhizopus arrhizus --- sterol pattern --- antifungal effectivity --- gas chromatography-mass spectrometry (GC-MS) --- posaconazole --- sterol biosynthesis --- sterol 14?-demethylase --- sterol C24-methyltransferase --- mechanism-based inactivators --- antifungals --- azoles --- antiparasitic drugs --- human African trypanosomiasis --- Chagas disease --- synthesis --- squalene cyclase --- cycloartenol synthase --- triterpene --- fern --- Polystichum --- terpene --- isoprenoid --- divalent metal co-factor ligation --- antioxidant --- cholesterol --- degeneration --- oxysterol --- retina --- Smith-Lemli-Opitz syndrome --- algal sterols --- ergosterol biosynthesis --- infectious disease --- lipidomics --- oxyphytosterol --- pharmacognosy --- phytosterol --- sterolomics --- lupeol --- keratinocytes --- fibroblasts --- wound healing --- cell migration --- UV-radiation --- ZnO --- toxicity --- sterol content --- cholesterol --- leishmania --- solanaceae --- withanolides --- aurelianolides --- phytosterols --- mesocarp --- oilseed --- maturity --- pod-blast --- ?-tocopherol --- oil bodies --- campesterol --- stigmasterol --- ?-sitosterol --- sterol --- C4-demethylation complex (C4DMC) --- 4-methylsterol --- hormone --- steroid --- development --- genetic disease --- bile alcohol --- cholestanoic acid --- oxysterol --- sterolomics --- enzyme-assisted derivatization --- electrospray ionization-mass spectrometry --- Girard reagent --- n/a

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