The dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes of Plasmodium vivax, as antifolate resistance-associated genes were used for drug resistance surveillance. A total of 375 P. vivax isolates collected from different geographical locations in China in 2009-2019 were used to sequence Pvdhfr and Pvdhps. The majority of the isolates harbored a mutant type allele for Pvdhfr (94.5%) and Pvdhps (68.2%). The most predominant point mutations were S117T/N (77.7%) in Pvdhfr and A383G (66.8%) in Pvdhps. Amino acid changes were identified at nine residues in Pvdhfr. A quadruple-mutant haplotype at 57, 58, 61, and 117 was the most frequent (57.4%) among 16 distinct Pvdhfr haplotypes. Mutations in Pvdhps were detected at six codons, and the double-mutant A383G/A553G was the most prevalent (39.3%). Pvdhfr exhibited a higher mutation prevalence and greater diversity than Pvdhps in China. Most isolates from Yunnan carried multiple mutant haplotypes, while the majority of samples from temperate regions and Hainan Island harbored the wild type or single mutant type. This study indicated that the antifolate resistance levels of P. vivax parasites were different across China and molecular markers could be used to rapidly monitor drug resistance. Results provided evidence for updating national drug policy and treatment guidelines.
Antimalarials/pharmacology* ; China/epidemiology* ; Drug Combinations ; Drug Resistance/genetics* ; Folic Acid Antagonists/pharmacology* ; Humans ; Mutation ; Plasmodium vivax/genetics* ; Prevalence

Methionine synthase (MS, EC2.1.1.13), a key enzyme in the folate metabolism area catalyzing methyl transfer from N5-methyltetrahydrofolate to homocysteine to give tetrahydrofolate and methionine, takes a core position in folate cycle, one-carbon-unit transfer and sculpture amino acid pathways. Cobalamin-dependent methionine synthase was purified from rat liver. The enzyme was purified 609-fold to near homogeneity by batch chromatography on DE-52, anion-exchange chromatography on Q Sepharose Fast Flow and CHT-I hydroxyapatite column and was identified by SDS-PAGE and Western blotting. The enzyme activity was determined by spectrophotometric assay. In addition, the influencing factor and optimal reaction condition were performed. The steady state kinetic of rat liver methionine synthase was similar to that of other mammalian cobalamin-dependent methionine synthase which employed a Ping-Pong mechanism. The result indicated that cobalamin-dependent methionine synthase purified from rat liver is suitable for screening and studying methionine synthase specific inhibitors.
5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase ; isolation & purification ; metabolism ; Animals ; Electrophoresis, Polyacrylamide Gel ; Folic Acid Antagonists ; pharmacology ; Liver ; chemistry ; Male ; Methotrexate ; pharmacology ; Quinazolines ; pharmacology ; Rats ; Rats, Wistar ; Tetrahydrofolates ; metabolism ; Thiophenes ; pharmacology

Pyrimidine derivatives have been the subject of much attention in pesticide and medicine fields owing to their unique biological properties. Particularly, a large number of these compounds have recently been reported to show substantial antitumor activities, and some of them have been investigated in clinical trials. Although these structurally novel compounds have a common chemical moiety of a pyrimidine ring, there are a variety of mechanisms of their antitumor action, such as, inhibition of cyclin-dependent-kinases, inhibition of protein tyrosine kinase, inhibition of carbonic anhydrases, inhibition of dihydrofolate reductase and disruption of microtubule assembly. In this paper, we described the latest advances in the research of such pyrimidine derivatives as antitumor drug according to their action on targets.
Animals ; Antineoplastic Agents ; chemistry ; pharmacology ; therapeutic use ; Carbonic Anhydrase Inhibitors ; pharmacology ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinases ; antagonists & inhibitors ; Folic Acid Antagonists ; pharmacology ; Humans ; Neoplasms ; drug therapy ; pathology ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Pyrimidines ; chemistry ; pharmacology ; therapeutic use ; Tetrahydrofolate Dehydrogenase ; pharmacology ; Tubulin Modulators ; pharmacology ; therapeutic use

OBJECTIVETo evaluate whether or not administration of folic acid and resveratrol have preventive effects on cleft palate formation as well as the comparison of the two drugs' s effects.

METHODSPregnant mice were randomly divided into 9 groups, with 8 mice in each group. The TCDD group mice were dosed with TCDD 28 microg/kg body weight on gestation day 10 (GD 10) animals in folic acid group were respectively dosed with folic acid 15, 10, 5 mg/kg and TCDD 28 microg/kg; resveratrol treated mice were divided into 3 groups: resveratrol 50 mg/kg were orally administered for 6 consecutive days, from gestational day GD 8 to GD13 in resveratrol (GD8-13 ) group; resveratrol 50 mg/kg were orally administered for 6 consecutive days, from gestational day GD 8 to GD13, followed hy an oral administered with TCDD on GD10 in resveratrol (GD8-13) + TCDD group; resveratrol 50mg/kg and TCDD 28 microg/kg were used by gavage administration at GD10 in resveratrol (GD10) + TCDD group. Control mice were treated with the same volume of water for 6 consecutive days from GD8 to GD13 and were given a single dose of corn oil on GD10. The pregnant mice weight and embryos, the number of live, cleft palate, dead and resorption fetal mice were recorded on GD 17.5. The coronal sections of the fetal mice heads were prepared at GD 17.5 and observed by microscopy.

RESULTSTotal frequency of clefts was 92.86% in TCDD group, 84.00% (15 mg), 73.08% (10 mg), 84.00% (5 mg) in folic acid + TCDD groups, 0% in resveratrol (GD10) group, 74.51% (GD10), 57.78% (GD8-13) in resveratrol + TCDD groups. The frequency of cleft was 0% in the control group. Compared with the control and the TCDD groups, there were significant differences in the number of live, dead and resorption fetal mice in TCCD + resveratrol (GD8-13) group (P < 0.05). No significant differences in embryonic weight, live fetuses weight, the number of live, dead and resorption fetal mice were found in the other groups (P > 0.05).

CONCLUSIONTest dose of folic acid and resveratrol both had certain antagonistic effect on cleft palate in mice induced by TCDD, with folic acid 10 mg/kg, resveratrol 50 mg/kg GD8-13 doses having stronger antagonistic action. Effects of both the two drugs have no significant difference, but resveratrol (50 mg/kg, GD8-13) significantly affects the fetal mice's growth and development under TCDD exposure in utero.

Abnormalities, Drug-Induced ; prevention & control ; Animals ; Cleft Palate ; chemically induced ; prevention & control ; Female ; Fetus ; Folic Acid ; administration & dosage ; pharmacology ; Humans ; Mice ; Mice, Inbred C57BL ; Polychlorinated Dibenzodioxins ; antagonists & inhibitors ; Pregnancy ; Random Allocation ; Stilbenes ; administration & dosage ; pharmacology ; Teratogens

Resistance of Plasmodium spp. to anti-malarial drugs is the primary obstacle in the fight against malaria, and molecular markers for the drug resistance have been applied as an adjunct in the surveillance of the resistance. In this study, we investigated the prevalence of mutations in pvmdr1, pvcrt-o, pvdhfr, and pvdhps genes in temperate-zone P. vivax parasites from central China. A total of 26 isolates were selected, including 8 which were previously shown to have a lower susceptibility to chloroquine in vitro. For pvmdr1, pvcrt-o, and pvdhps genes, no resistance-conferring mutations were discovered. However, a highly prevalent (69.2%), single-point mutation (S117N) was found in pvdhfr gene. In addition, tandem repeat polymorphisms existed in pvdhfr and pvdhps genes, which warranted further studies in relation to the parasite resistance to antifolate drugs. The study further suggests that P. vivax populations in central China may still be relatively susceptible to chloroquine and sulfadoxine-pyrimethamine.
Antimalarials/*pharmacology ; China ; Chloroquine/pharmacology ; DNA, Protozoan/chemistry/genetics ; Drug Resistance/*genetics ; Folic Acid Antagonists/pharmacology ; Genotype ; Humans ; Malaria, Vivax/epidemiology/*parasitology ; Plasmodium vivax/drug effects/*genetics/isolation & purification ; Point Mutation ; Polymorphism, Single Nucleotide/*genetics ; Prevalence ; Protozoan Proteins/genetics ; Sequence Analysis, DNA ; Tandem Repeat Sequences/*genetics