scholarly journals De Novo Biosynthesis of Deoxyribonucleic Acid Polymerase during Wheat Embryo Germination

1975 ◽  
Vol 55 (3) ◽  
pp. 437-442 ◽  
Author(s):  
Yves Y. Mory ◽  
David Chen ◽  
Sara Sarid
1966 ◽  
Vol 44 (11) ◽  
pp. 1435-1446 ◽  
Author(s):  
H. L. A. Tars ◽  
Joan Roy

Slices of immature salmon testes incorporated radioactive purine and pyrimidine bases and related nucleosides, deoxynucleosides, nucleotides, and deoxynucleotides into deoxyribonucleic acid (DNA). When DNA was extracted from the tissues and hydrolyzed, the purine and pyrimidine bases obtained were labeled in a manner which suggested that the radioactive substrates had been incorporated into DNA by recognized biosynthetic pathways involving "preformed" purines and pyrimidines and their derivatives. Since radioactive carbonate, glycine, and formate were not incorporated into the purines obtained from DNA, and radioactive formate only caused labeling of the thymine, it would appear unlikely that the de novo biosynthesis of purine and pyrimidine rings occurs in milts. C-1, C-6, and generally labeled glucose-14C caused labeling of the 2-deoxyribose, but not of the purines or pyrimidines, of DNA. Radioactive adenylic acid, deoxyuridylic acid, ribose 5-phosphate, and 5-phospho-α-D-ribofuranosyl-1-pyrophosphate also caused labeling of the 2-deoxyribose of DNA.


1979 ◽  
Vol 181 (1) ◽  
pp. 193-199 ◽  
Author(s):  
M Castroviejo ◽  
D Tharaud ◽  
B Mocquot ◽  
S Litvak

DNA synthesis starts about 12 h after water imbibition in wheat embryos. We have determined that noticeable amounts of labelled thymidine are found inside the embryo only after 6 hr of germination. DNA polymerase C from ungerminated wheat embryos decreased markedly in activity during the first hours of germination, whereas the activities of DNA polymerases A and B increased, having a maximum at about 15 h or germination. Serological evidence has suggested a clear antigenic relationship between DNA polymerases A and C. Although the pool of ATP increases rapidly after water imbibition, the increase in the pool of dNTP species was much slower.


2021 ◽  
Vol 22 (13) ◽  
pp. 7236
Author(s):  
Endah Dwi Hartuti ◽  
Takaya Sakura ◽  
Mohammed S. O. Tagod ◽  
Eri Yoshida ◽  
Xinying Wang ◽  
...  

Plasmodium falciparum’s resistance to available antimalarial drugs highlights the need for the development of novel drugs. Pyrimidine de novo biosynthesis is a validated drug target for the prevention and treatment of malaria infection. P. falciparum dihydroorotate dehydrogenase (PfDHODH) catalyzes the oxidation of dihydroorotate to orotate and utilize ubiquinone as an electron acceptor in the fourth step of pyrimidine de novo biosynthesis. PfDHODH is targeted by the inhibitor DSM265, which binds to a hydrophobic pocket located at the N-terminus where ubiquinone binds, which is known to be structurally divergent from the mammalian orthologue. In this study, we screened 40,400 compounds from the Kyoto University chemical library against recombinant PfDHODH. These studies led to the identification of 3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine and its derivatives as a new class of PfDHODH inhibitor. Moreover, the hit compounds identified in this study are selective for PfDHODH without inhibition of the human enzymes. Finally, this new scaffold of PfDHODH inhibitors showed growth inhibition activity against P. falciparum 3D7 with low toxicity to three human cell lines, providing a new starting point for antimalarial drug development.


2021 ◽  
Vol 22 (6) ◽  
pp. 3115
Author(s):  
Lorenzo Germelli ◽  
Eleonora Da Pozzo ◽  
Chiara Giacomelli ◽  
Chiara Tremolanti ◽  
Laura Marchetti ◽  
...  

Neuroactive steroids are potent modulators of microglial functions and are capable of counteracting their excessive reactivity. This action has mainly been ascribed to neuroactive steroids released from other sources, as microglia have been defined unable to produce neurosteroids de novo. Unexpectedly, immortalized murine microglia recently exhibited this de novo biosynthesis; herein, de novo neurosteroidogenesis was characterized in immortalized human microglia. The results demonstrated that C20 and HMC3 microglial cells constitutively express members of the neurosteroidogenesis multiprotein machinery—in particular, the transduceosome members StAR and TSPO, and the enzyme CYP11A1. Moreover, both cell lines produce pregnenolone and transcriptionally express the enzymes involved in neurosteroidogenesis. The high TSPO expression levels observed in microglia prompted us to assess its role in de novo neurosteroidogenesis. TSPO siRNA and TSPO synthetic ligand treatments were used to reduce and prompt TSPO function, respectively. The TSPO expression downregulation compromised the de novo neurosteroidogenesis and led to an increase in StAR expression, probably as a compensatory mechanism. The pharmacological TSPO stimulation the de novo neurosteroidogenesis improved in turn the neurosteroid-mediated release of Brain-Derived Neurotrophic Factor. In conclusion, these results demonstrated that de novo neurosteroidogenesis occurs in human microglia, unravelling a new mechanism potentially useful for future therapeutic purposes.


Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1469
Author(s):  
Patricia M. Rusu ◽  
Andrea Y. Chan ◽  
Mathias Heikenwalder ◽  
Oliver J. Müller ◽  
Adam J. Rose

Prior studies have reported that dietary protein dilution (DPD) or amino acid dilution promotes heightened water intake (i.e., hyperdipsia) however, the exact dietary requirements and the mechanism responsible for this effect are still unknown. Here, we show that dietary amino acid (AA) restriction is sufficient and required to drive hyperdipsia during DPD. Our studies demonstrate that particularly dietary essential AA (EAA) restriction, but not non-EAA, is responsible for the hyperdipsic effect of total dietary AA restriction (DAR). Additionally, by using diets with varying amounts of individual EAA under constant total AA supply, we demonstrate that restriction of threonine (Thr) or tryptophan (Trp) is mandatory and sufficient for the effects of DAR on hyperdipsia and that liver-derived fibroblast growth factor 21 (FGF21) is required for this hyperdipsic effect. Strikingly, artificially introducing Thr de novo biosynthesis in hepatocytes reversed hyperdipsia during DAR. In summary, our results show that the DPD effects on hyperdipsia are induced by the deprivation of Thr and Trp, and in turn, via liver/hepatocyte-derived FGF21.


Author(s):  
Bastian Broschwitz ◽  
Lorena Prager ◽  
Tamara Pokorny ◽  
Joachim Ruther

Author(s):  
Weixian Li ◽  
Xiaohui Ma ◽  
Guodong Li ◽  
Aili Zhang ◽  
Dong Wang ◽  
...  
Keyword(s):  
De Novo ◽  

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