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Modulators of hypothalamic-pituitary-gonadal axis for the control of spermatogenesis and sperm quality in vertebrates

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193585 Year: Pages: 159 DOI: 10.3389/978-2-88919-358-5 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General)
Added to DOAB on : 2016-03-10 08:14:32
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Spermatogenesis is a process highly conserved throughout vertebrate species and is mainly under hypothalamic-pituitary control. It occurs in the testis in a stepwise fashion so that committed spermatogonia develop into spermatocytes and enter meiosis to produce round spermatids. These undergo a morphological transformation (spermiogenesis) into mature spermatids (i.e.: spermatozoa), which are differentially released from Sertoli cells (spermiation) depending on the species. In mammals, further transformations are necessary to form mature spermatozoa, suitable for fertilization. Gonadotropins, mainly responsive to gonadotropin-releasing hormone, control spermatogenesis through specific receptors located at the gonadal level. However, besides the endocrine route, the chemical mediators may also act locally in the gonad. Indeed, it is documented that testis physiology, including steroidogenesis and spermatogenesis, does not fully account for traditional endocrine control but an intragonadal network of autocrine and/or paracrine regulators also exists, whose activity, via cell-to-cell communication, regulates germ cell progression and development of qualitatively mature spermatozoa. Of note, a number of testicular modulators, such as gonadotropin releasing hormone, Kiss-peptin, endocannabinoids, has been early isolated in the brain and latest in the gonads. To fully understand precise mechanisms underlying the functional interaction of this intricate network, needless to say, it is crucially required to have detailed information about modulators and target cells. Through synergy between the respective specializations of all the authors, this topic reviewed emerging knowledge about neuroendocrine and local mediators controlling germ cell progression and maturation.

The Evolving Telomeres

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198818 Year: Pages: 74 DOI: 10.3389/978-2-88919-881-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Genetics
Added to DOAB on : 2016-01-19 14:05:46
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What controls the different rates of evolution to give rise to conserved and divergent proteins and RNAs? How many trials until evolution can adapt to physiological changes? Every organism has arisen through multiple molecular changes, and the mechanisms that are employed (mutagenesis, recombination, transposition) have been an issue left to the elegant discipline of evolutionary biology. But behind the theory are realities that we have yet to ascertain: How does an evolving cell accommodate its requirements for both conserving its essential functions, while also providing a selective advantage? In this volume, we focus on the evolution of the eukaryotic telomere, the ribo-nuclear protein complex at the end of a linear chromosome. The telomere is an example of a single chromosomal element that must function to maintain genomic stability. The telomeres of all species must provide a means to avoid the attrition from semi-conservative DNA replication and a means of telomere elongation (the telomere replication problem). For example, telomerase is the most well-studied mechanism to circumvent telomere attrition by adding the short repeats that constitutes most telomeres. The telomere must also guard against the multiple activities that can act on an unprotected double strand break requiring a window (or checkpoint) to compensate for telomere sequence loss as well as protection against non-specific processes (the telomere protection problem). This volume describes a range of methodologies including mechanistic studies, phylogenetic comparisons and data-based theoretical approaches to study telomere evolution over a broad spectrum of organisms that includes plants, animals and fungi. In telomeres that are elongated by telomerases, different components have widely different rates of evolution. Telomerases evolved from roots in archaebacteria including splicing factors and LTR-transposition. At the conserved level, the telomere is a rebel among double strand breaks (DSBs) and has altered the function of the highly conserved proteins of the ATM pathway into an elegant means of protecting the chromosome end and maintaining telomere size homeostasis through a competition of positive and negative factors. This homeostasis, coupled with highly conserved capping proteins, is sufficient for protection. However, far more proteins are present at the telomere to provide additional species-specific functions. Do these proteins provide insight into how the cell allows for rapid change without self-destruction?

Bats in the Anthropocene: Conservation of Bats in a Changing World

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ISBN: 9783319252186 9783319252209 Year: Pages: 606 DOI: 10.1007/978-3-319-25220-9 Language: English
Publisher: Springer Nature
Subject: Environmental Sciences --- Ecology
Added to DOAB on : 2016-04-12 14:46:09
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This book focuses on central themes related to the conservation of bats. It details their response to land-use change and management practices, intensified urbanization and roost disturbance and loss. Increasing interactions between humans and bats as a result of hunting, disease relationships, occupation of human dwellings, and conflict over fruit crops are explored in depth. Finally, contributors highlight the roles that taxonomy, conservation networks and conservation psychology have to play in conserving this imperilled but vital taxon.With over 1300 species, bats are the second largest order of mammals, yet as the Anthropocene dawns, bat populations around the world are in decline. Greater understanding of the anthropogenic drivers of this decline and exploration of possible mitigation measures are urgently needed if we are to retain global bat diversity in the coming decades. This book brings together teams of international experts to provide a global review of current understanding and recommend directions for future research and mitigation.

Brain Asymmetry of Structure And/Or Function

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ISBN: 9783038425502 9783038425519 Year: Pages: VIII, 148 DOI: 10.3390/books978-3-03842-551-9 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology
Added to DOAB on : 2017-12-28 13:57:29
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This edited book brings together research reports on the asymmetry of brain function in various species, including humans, dogs, birds, lizards and bees. As shown in a wide range of species, and, as we now know, not solely in humans, the left and right sides of the brain process information in different ways and control different responses or patterns of behaviour. Since this discovery, many new methods have become available to reveal the processes involved in the development, function and evolution of this important attribute of the brain. Chapters consider the evidence for asymmetry of sensory receptors, left–right differences in information processing and asymmetrical control of behaviour. The latter includes lateralization of bird song and use of the magnetic compass in navigation. Other chapters report studies on handedness, hemispheric asymmetries in emotional processing and perception of symmetry in humans. The importance of the degree, or strength, of asymmetry is discussed and the conclusion is that asymmetry of the brain enhances its efficiency. Other chapters provide evidence that early experience influences the development of asymmetry. All of the contributors have strong backgrounds in research and they discuss up-to-date discoveries on lateralized brain and behaviour.

Reorienting Indian Agriculture: Challenges and Opportunities

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ISBN: 9781786395177; 9781786395184; 9781786395191 Year: Pages: 336 DOI: 10.1079/9781786395177.0000 Language: English
Publisher: CABI
Subject: Agriculture (General)
Added to DOAB on : 2020-10-16 16:20:14
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This book covers various aspects of Indian agriculture. It consists of 32 chapters that are presented in 12 parts with the following headings: agricultural scenario; revolutions in agriculture; reorienting agricultural research for innovation; improving productivity and production; harnessing agricultural biotechnology; managing plant genetic resources; the role and growth of the seed sector; integrated natural resource management; impact of climate change; innovation in extension; the role of women and youth; and policy reforms for accelerated growth.

Organic Food Systems: Meeting the Needs of Southern Africa

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ISBN: 9781786399601; 9781786399625; 9781786399618 Year: Pages: 365 DOI: 10.1079/9781786399601.0000 Language: English
Publisher: CABI
Subject: Agriculture (General) --- Plant Sciences
Added to DOAB on : 2020-10-16 15:57:49
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This book reports on long-term comparative organic farming systems' research trials carried out over the last 5 years in the Southern Cape of South Africa, as well as research into the successes and failures of the organic sector and the technical tools required for sustainable development in South Africa, Zambia, Uganda and Tanzania. It includes 24 chapters organized into 4 parts. Part 1 (Chapters 1-6) discusses the historical development of organic farming systems, examines the global issues which confront us, and develops some concepts showing a progression in small-scale farmer development and how this can be supported with appropriate training and policy. The difference between national food self-sufficiency and household food security is examined, and the organic sector is introduced. Part 2 (Chapters 7-14) deals with capacity building and climate change. Holistic systems, inclusive participatory approaches, institution building and experiential learning are examined. Organic food production, farmer training, value chains, impact of drought on food prices and food availability, and urban water and energy use efficiency are described. Part 3 (Chapters 15-22) presents evidence on how to support organic farmers. It starts with 2 case studies on the well-developed organic sector in Uganda and the developing one in Zambia. The following chapters discuss soil carbon determination, comparison of organic and conventional farming systems, pest and disease control (e.g., chemical, holistic and biological control), soil fumigation, soil microbiology in organic and conventional systems, soil fertility changes and crop yield. Part 4 (Chapters 23-24) makes strategic suggestions about how to upscale organic farming and organic food systems in Southern Africa. This book is a vital resource for all stakeholders in organic agriculture.

Marine Anti-inflammatory Agents

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ISBN: 9783039215720 9783039215737 Year: Pages: 248 DOI: 10.3390/books978-3-03921-573-7 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General)
Added to DOAB on : 2019-12-09 11:49:16
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Acute inflammation is a highly regulated process, and its dysregulation can lead to the development of a chronic inflammatory state which is believed to play a main role in the pathogenesis of many diseases, including cancer. In recent years, the need to find new anti-inflammatory molecules has raised the scientific community´s interest for marine natural products. In this regard, the marine environment represents a source for isolating a wealth of bioactive compounds. In this Special Issue, the reported products have been obtained from microalgae, sea cucumber, octopus, squid, red alga-derived fungus, cnidarians, hard-shelled mussel, and sponges.

Keywords

THP-1 macrophages --- anti-inflammatory --- TLR4 --- NF-?B --- MAPK --- SPR analysis --- glycolipids --- MGDG --- skin --- inflammation --- epidermal hyperplasia --- microalgae --- Isochrysis galbana --- Frondanol --- Cucumaria frondosa --- DSS colitis --- colon inflammation --- zoantharia --- Tropical Eastern Pacific --- Zoanthus pulchellus --- zoanthamine --- inflammation --- fucoxanthin --- inflammation --- epidermal hyperplasia --- UVB --- photoprotection --- 6-bromoindole --- Geodia barretti --- anti-inflammatory activity --- dendritic cells --- T cell differentiation --- poor blood circulation --- Ecklonia cava --- phlorotannins --- pyrogallol-phloroglucinol-6,6-bieckol --- functional ingredients --- endothelial cell death --- vascular smooth muscle cell proliferation and migration --- inflammation --- anti-inflammatory --- bioactive molecules --- microalgae --- polysaccharides --- carotenoids --- polyunsaturated fatty acids --- fucoxanthin --- ultraviolet B --- denervation --- seafood waste --- polyunsaturated fatty acid --- NO inhibition --- fish oil --- marine nutraceuticals --- fish oil --- omega-3 --- eicosapentaenoic acid --- docosahexaenoic acid --- inflammation --- eicosanoid --- cytokine --- surgery --- critical illness --- parenteral nutrition --- signal transducer and activator of transcription 3 (STAT3) --- matrix metalloproteinases-9 (MMP-9) --- interleukin (IL) --- lipopolysaccharide (LPS) --- acute sickness behavior --- acute lung injury (ALI) --- prostaglandins --- clavulones --- punaglandins --- thromboxane --- inflammation --- marine vertebrates --- marine invertebrates --- diatoms --- macroalgae --- fucoxanthin --- rosmarinic acid --- NRLP3 --- inflammasome --- anti-oxidative --- anti-inflammatory --- photo-protection --- UVB

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