China 
Africa 
Explore chapters and articles related to this topic
Phosphodiesterases
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2020
Moritz Helmstädter, Manfred Schubert-Zsilavecz
Enzymes of the family of cyclic nucleotide phosphodiesterases (PDE) are known to catalyze the breakdown of cyclic cAMP and cGMP. Since cyclic nucleotides (cN) play a such a crucial role as second messengers, phosphodiesterases have a key role in modulating signal transduction in various cell types by regulating the cellular levels of cNs by controlling their rates of degradation (Bender, 2006) (Fig. 2.1). Dysfunctions in PDE activities are associated with asthma, erectile dysfunction (ED), chronic obstructive pulmonary disease (COPD), pulmonary arterial hypertension, a plethora of autoimmune diseases, infertility, hypertension, intermittent claudication, heart failure, schizophrenia, dementia, stroke and depression (Francis et al., 2011a; Maurice et al., 2014).
Biomolecules
Published in Volodymyr Ivanov, Environmental Microbiology for Engineers, 2020
A cyclic nucleotide contains a single phosphate group connected by two –P–O–C– (phosphodiester) bonds with the sugar. A change of their concentration in a cell, especially the most important cyclic adenosine monophosphate (cAMP), results in the formation or hydrolysis of one –P–O–C– bond. Even a low concentration of cAMP and some other cyclic nucleotides affects the activities of many enzymes, so cyclic nucleotides control cell metabolism and cell development.
Macrocyclic Receptors for Biomolecules and Biochemical Sensing
Published in Satish Kumar, Priya Ranjan Sahoo, Violet Rajeshwari Macwan, Jaspreet Kaur, Mukesh, Rachana Sahney, Macrocyclic Receptors for Environmental and Biosensing Applications, 2022
Satish Kumar, Priya Ranjan Sahoo, Violet Rajeshwari Macwan, Jaspreet Kaur, Mukesh, Rachana Sahney
Cyclic nucleotides, adenosine-3′,5'-monophosphate (cAMP) and cyclic guanosine-3′,5'-monophosphate (cGMP) are important `second messengers’ involved as modulators of physiological processes, such as regulating neuronal, glandular, cardiovascular, immune mechanism, nervous system, cell growth and differentiation. The nucleotides relay signals received at receptors on the cell surface— such as the arrival of protein hormones, growth factors, etc., to target molecules in the cytosol and/or nucleus. But in addition to their job as relay molecules, second messengers serve to greatly amplify the strength of the signal. These small cyclic nucleotides as second messengers can bind to cyclic nucleotide-gated ion channels and target proteins like protein kinases (protein kinase A and G) (Lucas et al. 2000; Kaupp and Seifert 2002). Modulation of intracellular cAMP/cGMP concentrations occurs by activation or inhibition of adenylyl/guanylyl cyclases, the cAMP and cGMP synthesizing enzymes. To inhibit signaling, both second messengers are degraded by different phosphodiesterases (PDEs) with more or less specificity for either cAMP or cGMP (Beavo and Brunton 2002; Conti and Beavo 2007; Oeckl and Ferger 2012). Owing to the wide distribution of this second messenger system, an imbalance in its homeostatic regulation leads to a variety of pathological states, and the system is targeted for the treatment of several diseases such as cancer, cardiovascular, neurodegenerative and psychiatric disorders (Reffelmann and Kloner 2009; Reneerkens et al. 2009; Savai et al. 2010). Guanosine 3′,5'-bispyrophosphate (ppGpp) is another important nucleotide found in bacteria. It is usually produced during amino acid starvation which further slows down protein synthesis. Hence cAMP and cGMP measurement could serve as valuable biomarkers to indicate normal biological and pathogenic processes as well as pharmacological responses to a therapeutic intervention.
Numerical modeling of DNA nucleotides binding process mechanics considering oscillations
Published in Mechanics of Advanced Materials and Structures, 2022
The nucleotide is an important part of human aging research. A single nucleotide polymorphism (SNP, rs189037) in the promoter region of ATM gene was identified, and significant association between CT genotype and longevity was observed by Chen et al. [1]. Single-nucleotide polymorphisms in DNA repair genes relation to longevity were observed by Cho and Suh [2]. Jobson et al. [3] mentioned possible link between changes in amino acid composition shifts and adaptive evolution of mitochondrial proteomes, providing a longer lifespan. Noma [4] mentioned, that expression regulation of genetic information, and regulation of cell proliferation and apoptosis, are linked as an extension of nucleotide and nucleoside metabolism. Nucleotide dynamics studies are becoming increasingly important. Cyclic nucleotide dynamics in neurons were analyzed by Gorshkov and Zhang [5].
Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics
Published in Critical Reviews in Environmental Science and Technology, 2022
Tomer Malchi, Sara Eyal, Henryk Czosnek, Moshe Shenker, Benny Chefetz
There are numerous examples of analogies and homologies of receptors between animals and plants, and examples of such are transmembrane ion-channel receptors, transmembrane G-protein-coupled receptors and transmembrane receptors within cytosolic domains. Transmembrane ion-channel receptors such as voltage-gated ion channels regulate the ionic balance of the cell and cellular processes. Plant ion channel families exhibit homologies to animal proteins, and include hyperpolarization-and depolarization-activated Shaker-type potassium channels, chloride transporters/channels, cyclic nucleotide–gated channels, and ionotropic glutamate receptor homologs (Ward et al., 2009). Transmembrane G-protein-coupled receptors can activate a signal-transduction pathway that alters cellular processes through the activation of a second messenger system. Heterotrimeric G protein signaling regulates a wide range of growth and developmental processes in both animals and plants, but the two kingdoms are believed to have differences in protein structure, subunit composition and different G-protein-associated receptors (Stateczny et al., 2016; Trusov & Botella, 2016);
Strategies in improving plant salinity resistance and use of salinity resistant plants for economic sustainability
Published in Critical Reviews in Environmental Science and Technology, 2022
Neelma Munir, Maria Hasnain, Ute Roessner, Zainul Abideen
Salt exclusion is defined as the plant’s ability to exclude NaCl through filtration at the surface of the root. Membranes of roots protect salt accumulation in the cytoplasm by excluding most of the sodium and chloride in the soil solution or by salt accumulation at root and root/stem junctions (Godfrey et al., 2019). This in turn reduce the shoot Na+ and Cl- loading and protect plants from salt toxicity. The pericyclic and xylem parenchyma cells, root cortex and phloem cells are the key locations for salt exclusion in plants. Blocking Na+ influx into the root by salt exclusion is performed by several transporters activated by the SOS (salt overly sensitive) signaling pathway and nonselective cation channels (Tester, 2003). Two important members of the nonselective cation channels may be the cyclic nucleotide-gate channels (the CNGCs) and the glutamate-activated channels (the GLRs). In the Ca2+-insensitive pathway, nonselective cation channels (NSCCs) pathways like HKT1 (high-affinity potassium transporter), KUP (K+ uptake permeases), and HAK (high affinity K+ transporter) may be involved (Munns, 2005; Tester, 2003).