Vitamin B1 de novo synthesis in the human malaria parasite Plasmodium falciparum depends on external provision of 4-amino-5-hydroxymethyl-2-methylpyrimidine.

Vitamin B1 (thiamine) is an essential cofactor for several key enzymes of carbohydrate metabolism. Mammals have to salvage this crucial nutrient from their diet to complement their deficiency of de novo synthesis. In contrast, bacteria, fungi, plants and, as reported here, Plasmodium falciparum, possess a vitamin B1 biosynthesis pathway.

Thi20, a remarkable enzyme from Saccharomyces cerevisiae with dual thiamin biosynthetic and degradation activities.

Saccharomyces cerevisiae Thi20 is a fusion protein with homology to Bacillus subtilis ThiD and TenA. The N-terminus of Thi20 has significant sequence homology to B. subtilis ThiD, while the C-terminus has homology to B.

Molecular characterization of a gene encoding a cystatin expressed in the stems of American chestnut (Castanea dentata).

A cDNA clone with similarity to genes encoding cystatin was recently isolated from a cDNA library created using mRNA extracted from stem tissues of Castanea dentata (Marsh.) Borkh. (CASde:Pic1).