Rosmarinus officinalis L. is widely distributed in Saudi Arabia. However, only a few studies have been reported regarding this species. In study, we investigated the phytochemical analysis of R. essential oil using GC-MS order to identify its major components; vitro antimicrobial activity was also evaluated disc diffusion assay against gram-positive (S. aureus) and gram-negative bacteria (E. co...

The antifolate combination of pyrimethamine (PM) and sulfadoxine (SD) is the last affordable drug combination available for wide-scale treatment of falciparum malaria in Africa. Wherever this combination has been used, drug-resistant parasites have been selected rapidly. A study of PM-SD effectiveness carried out between 1997 and 1999 at Kilifi on the Kenyan coast has shown the emergence of RI ...

Human-derived Pneumocystis carinii dihydrofolate reductase (DHFR) was expressed in a Saccharomyces cerevisiae strain whose growth depends on complementation by this enzyme. We utilized a quantitative assay to measure the sensitivity of this yeast strain to DHFR inhibitors. This assay should be useful for identifying new inhibitors of human-derived P. carinii DHFR.

Amplification of the dihydrofolate reductase gene (Dhfr) by methotrexate (Mtx) exposure is commonly used for recombinant protein expression in Chinese hamster ovary (CHO) cells. However, this method is both time- and labor-intensive, and the high-producing cells that are generated are frequently unstable in culture. Another gene amplification method is based on using a plasmid bearing a mammali...

It is shown by analysis of a cyclic enzymatic network that the presence zero net flux/current cycles impose strong thermodynamic constraints on values kinetic parameters. Thermodynamic carried out for four-node pyramidal reaction involving conversion 7,8-­dihydrofolate (H2F) and NADPH in H+ to 5,6,7,8-­tetrahydrofolate (H4F) NADP+ catalyzed universal enzyme dihydrofolate reductase (DHFR). The c...

We investigated Pneumocystis jirovecii dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) genes for mutations in 25 Chinese HIV-infected patients with P. jirovecii pneumonia. We identified DHPS mutations in 3 (12%) patients and DHFR mutations in 1 (4%) patient. The prevalence of DHPS and DHFR mutations in China remains low, as it does in other developing countries.

PURPOSE The aim of this study is to investigate the effect of genetic variations and the expression of the reduced folate carrier (RFC) and dihydrofolate reductase (DHFR) on the drug sensitivity to methotrexate (MTX) in different cancer cell lines. MATERIALS AND METHODS We examined the six human cancer cell lines (MCF-7, AGS, A549, NCI-H23, HCT-116 and Saos-2). The cytotoxicity of MTX was mea...

High-dose methotrexate is a major component of current protocols for the treatment of osteosarcoma, but some tumors seem to be resistant. Potential mechanisms of resistance include decreased transport through the reduced folate carrier (RFC) and increased expression of dihydrofolate reductase (DHFR). To investigate methotrexate resistance, tumors were obtained from 42 patients with high-grade o...

It is an urgent need to develop new drugs for Mycobacterium tuberculosis (Mtb), and the enzyme, dihydrofolate reductase (DHFR) is a recognised drug target. The crystal structures of methotrexate binding to mt- and h-DHFR separately indicate that the glycerol (GOL) binding site is likely to be critical for the function of mt-DHFR selective inhibitors. We have used in silico methods to screen NCI...

Increasing resistance of Plasmodium falciparum malaria parasites to chloroquine and the dihydrofolate reductase (DHFR) inhibitors pyrimethamine and cycloguanil have sparked renewed interest in the antimalarial drugs WR99210 and proguanil, the cycloguanil precursor. To investigate suggestions that WR99210 and proguanil act against a target other than the reductase moiety of the P. falciparum bif...