The enzymatic synthesis of dihydropteroate or dihydrofolate from 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine and p-aminobenaoate or p-aminobenzoylglutamate by bacterial extracts has been shown to require adenosine triphosphate (I-3). It has been postulated that a phosphorylated pteridine intermediate is involved before synthesis of folate-like compounds. Jaenicke and Chan (4) reported tha...

The structural gene for human argininosuccinate synthetase [L-citrulline:L-aspartate ligase (AMP-forming), EC 6.3.4.5] was transferred to argininosuccinate synthetase-deficient Chinese hamster cells via metaphase chromosomes isolated from human lymphoblast line MGL8D1, a constitutive overproducer of argininosuccinate synthetase, and from its repressible parent, MGL8B2. Argininosuccinate synthet...

Sulfadoxine is predominantly used in combination with pyrimethamine, commonly known as Fansidar, for the treatment of Plasmodium falciparum. This combination is usually less effective against Plasmodium vivax, probably due to the innate refractoriness of parasites to the sulfadoxine component. To investigate this mechanism of resistance by P. vivax to sulfadoxine, we cloned and sequenced the P....

The plant enzyme 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase/7,8-dihydropteroate synthase (HPPK/DHPS) is a mitochondrial bifunctional protein involved in tetrahydrofolate synthesis. The first domain (HPPK) catalyses the pyrophosphorylation of 6-hydroxymethyl-7,8-dihydropterin (dihydropterin) by ATP, leading to 6-hydroxymethyl-7,8-dihydropterin pyrophosphate (dihydropterinPP(i)) and AMP....

BACKGROUND & OBJECTIVES Antimalarial resistance in P. falciparum malaria parasite creates a serious obstacle in malaria control programme. Keeping this in mind, in the present study antifolate resistance associated point mutations in P. falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase (Pfdhps) genes among the field samples in Arunachal Pradesh were determined. METHOD...

There are few published reports of mutations in dihydropteroate synthetase (dhps) and dihydrofolate reductase (dhfr) genes in P. falciparum populations in Nigeria, but one previous study has recorded a novel dhps mutation at codon 431 among infections imported to the United Kingdom from Nigeria. To assess how widespread this mutation is among parasites in different parts of the country and cons...

The combination of sulfadoxine-pyrimethamine (SP) is used as a second line of therapy for the treatment of uncomplicated chloroquine-resistant Plasmodium falciparum malaria. Resistance to SP arises due to certain point mutations in the genes for the dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) enzymes of the parasite. We have analyzed these mutations in 312 field isolate...

Described in 2005 by Bonnefond, L. et al, IARS2 (OMIM 612801) is a mitochondrial isoleucyl-tRNA synthetase encoded the nucleus. Phenotypically, mutation expressed broad clinical spectrum, which includes Leigh Syndrome (LS) as well extra-neurological effects. We described 7-year-old boy who presented global developmental delay, hypotonia and epilepsy, evolving with epileptic encephalopathy. An M...

The dihydropteroate synthase (dhps) genes of 44 P. malariae strains from four Asian countries were isolated. Only a limited number of polymorphisms were observed. Comparison with homologous mutations in other Plasmodium species showed that these polymorphisms are unlikely to be associated with sulfadoxine resistance.

Sulfonamides and trimethoprim have been used for many decades as efficient and inexpensive antibacterial agents for animals and man. Resistance to both has, however, spread extensively and rapidly. This is mainly due to the horizontal spread of resistance genes, expressing drug-insensitive variants of the target enzymes dihydropteroate synthase and dihydrofolate reductase, for sulfonamide and t...