China
Africa
Explore chapters and articles related to this topic
Ritualistic and Medicinal Plants from Marajó-PA Island
Published in Mahendra Rai, Shandesh Bhattarai, Chistiane M. Feitosa, Ethnopharmacology of Wild Plants, 2021
Paulo Wender Portal Gomes, Luiza Helena da Silva Martins, Paulo Weslem Portal Gomes, Emilli Roberta Sousa Pereira, Abraão de Jesus Barbosa Muribeca, Andrea Komesu, Mahendra Rai
Terpenes are produced in the Pyruvate +3 molecules of phosphoglyceraldehyde and mevalonic acid (HMG-CoA reductase). According to Dewick (2009), these compounds form a diversified group, that is, a family of metabolites derived from C5 isoprene, which links at the two molecular ends. Some common structures have carbon skeleton derived from (C5)n and are classified as hemiterpenes (C5), monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), esteresterpenes (C25), triterpenes (C30) and tetraterpenes (C40). The precursor is isopentenyl pyrophosphate (IPP), which can be obtained by two different routes (Figure 14.3).
Secondary Metabolites from Clerodendrum Infortunatum L.: Their Bioactivities and Health Benefits
Published in Hafiz Ansar Rasul Suleria, Megh R. Goyal, Health Benefits of Secondary Phytocompounds from Plant and Marine Sources, 2021
R. L. Helen, K. Jayesh, S. Syama, M. S. Latha
Terpenes are a diverse group containing one or more five-carbon isoprene units. They are synthesized from common precursor isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) via two independent pathways: the cytosolic mevalonic acid (MVA) pathway and the plastid localized methylerythritol phosphate (MEP) pathway [89]. According to the isoprene units present, terpenoids are categorized into: hemiterpenes (C5), monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), triterpenes (C30), etc. Terpenoids function as plant and animal hormones, membrane lipids, insect attractants, antifeedants, mediators of the electron transport system, and play a major role in the plant-environment interaction [35].
Implication of Mitochondrial Coenzyme Q10 (Ubiquinone) in Alzheimer’s Disease *
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
Sayantan Maitra, Dibyendu Dutta
The precursor of the quinone ring is only 4-hydroxybenzoic acid (4-HB), which is derived from tyrosine. Mevalonate pathway is the main route to synthesize the isoprenoid tail, which is also common to cholesterol biosynthesis. The initial part of the mevalonate pathway involves the condensation of three acetyl-CoA to form 3-hydroxy-3-methylglutaryl-CoA by HMG-CoA reductase, which is the main regulatory enzyme in cholesterol biosynthesis. Mevalonate is subsequently phosphorylated in two steps by mevalonate kinase (MVK) and phosphomevalonate kinase (PMVK). Then, decarboxylation of mevalonate pyrophosphate yields isopentenyl pyrophosphate (IPP), which is the precursor of farnesyl pyrophosphate (FPP) and the building block for the biosynthesis of dolichol and the side chain of CoQ. Isomerization of IPP gives dimethylallyl pyrophosphate (DMAPP), and FPP synthase utilizes IPP and DMAPP to make FPP with the intermediary formation of geranyl pyrophosphate (GPP). FPP is further converted into cholesterol, dolichols, and CoQ [6]. Decalyprenyl diphosphate synthase (DPS) is a heterotetramer consisting of two different proteins, namely, PDSS1 and PDSS2. DPS catalyzes the condensation of IPP and FPP to produce ten units of prenyldiphosphate (decaprenyl diphosphate). 4-Hydroxybenzoic acid-decaprenyl diphosphate transferase (encoded by CoQ2 gene in humans) catalyzes the condensation of PHB with the isoprenoid tail to yield CoQ10 [7,8].
PD-1 checkpoint blockade enhances adoptive immunotherapy by human Vγ2Vδ2 T cells against human prostate cancer
Published in OncoImmunology, 2021
Mohanad H. Nada, Hong Wang, Auter J. Hussein, Yoshimasa Tanaka, Craig T. Morita
Stimulation of Vγ2Vδ2 T cells by this wide variety of microbial pathogens is through their TCRs. Unlike conventional CD8 and CD4 αβ T cells that respond to peptides presented by MHC class I and class II molecules, Vγ2Vδ2 TCRs are triggered by shared intracellular isoprenoid metabolites and other phosphorylated metabolites also commonly termed as phosphoantigens. Foreign phosphorylated metabolites, such (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate in the 2-C-methyl-D-erythritol 4-phosphate isoprenoid synthesis pathway, or overproduced endogenous isoprenoid metabolites, such as isopentenyl pyrophosphate (IPP) in the mevalonate pathway,4 are sensed by the intracellular B30.2 domain of BTN3A1.5,6 Binding is signaled to its extracellular domain through an unknown mechanism and, in conjunction with BTN2A1,7,8 leads to recognition by the Vγ2Vδ2 TCR and T cell activation. This sensor system allows Vγ2Vδ2 T cells to surveil the cytoplasm of cells and eliminate those with aberrant isoprenoid metabolism because of mutagenesis or infection.
Can Plasmodium’s tricks for enhancing its transmission be turned against the parasite? New hopes for vector control
Published in Pathogens and Global Health, 2019
S. Noushin Emami, Melika Hajkazemian, Raimondas Mozūraitis
Isoprenoids are widespread molecules and are necessary for all living organisms [58]. These molecules are involved in a vast spectrum of metabolic processes and serve as building blocks in the synthesis of various compounds such as cholesterol, steroid hormones and vitamins [59]. Animals, fungi and a few bacteria produce isoprenoids through a biosynthetic route called mevalonate pathway. By contrast, eubacteria, plastid-containing eukaryotes and most bacteria use an alternate metabolic route, the non-mevalonate or methylerythritol phosphate (MEP) pathway. Plants use both pathways, the chloroplast-localized MEP pathway that is used for biosynthesis of the terpene volatiles that contributs their characteristic flavors and fragrances [60]. MEP pathway is used by parasitic apicomplaxan protozoa, including Plasmodium (reviewed in [61]). The MEP pathway is one of the recognizable pathways in malaria parasite apicoplast and this pathway might have evolved due to its lower energy consumption (reviewed in [45]). Due to its non-host specificity, biochemical reactions of MEP pathway have been favored as a highlighted target for novel antiparasitic drugs in human host. For example, fosmidomycin and its derivative, FR-900098 have an antibiotic activity that targets DOXP reductoisomerase and inhibits the growth of asexual stage of malaria parasite [62]. Parasites lost their apicoplast after non-antifolate antibiotic treatments such as doxycycline. Interestingly, parasite growth (asexual stage) is rescued upon simultaneous supplementation with the central isoprenoid precursor, isopentenyl pyrophosphate (IPP) [63].
γδ cell-based immunotherapy for cancer
Published in Expert Opinion on Biological Therapy, 2019
Elena Lo Presti, Anna Maria Corsale, Francesco Dieli, Serena Meraviglia
Human γδ T lymphocytes are generally defined by the Vδ chain used. The most abundant (up to 70%) γδ T lymphocytes in human adult blood and secondary lymphoid organs express a TCR heterodimer composed of the Vγ9 and Vδ2 chains [1]. These cells, commonly identified as Vγ9Vδ2 T lymphocytes, specifically recognize a new class of pyrophosphate metabolites called phosphoantigens (PAgs), which derive either from the host mevalonate (MVA) pathway (isopentenyl pyrophosphate, IPP) [2] or the microbial non-mevalonate Rohmer pathway ((E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate, HMB-PP) [3]. PAg recognition by Vγ9Vδ2 T cells requires butyrophilin-3A1 (CD277) [4–6]. In accordance with the very limited antigenic repertoire, the Vγ9Vδ2 TCR repertoire is invariant or semi-invariant, consistent with an innate-like modality of PAg recognition [7,8]. However, recent data [9] suggest that in addition to PAg-reactive Vγ9Vδ2 T lymphocytes, the Vδ2 population includes a distinct subset of Vγ9− T lymphocytes with a very diverse repertoire established by birth and with adaptive characteristics.