Protein geranylgeranyltransferase-I of Trypanosoma cruzi.

Protein geranylgeranyltransferase type I (PGGT-I) and protein farnesyltransferase (PFT) occur in many eukaryotic cells. Both consist of two subunits, the common alpha subunit and a distinct beta subunit. In the gene database of protozoa Trypanosoma cruzi, the causative agent of Chagas' disease, a putative protein that consists of 401 amino acids with approximately 20% amino acid sequence identity to the PGGT-I beta of other species was identified, cloned, and characterized.

C-terminal proteolysis of prenylated proteins in trypanosomatids and RNA interference of enzymes required for the post-translational processing pathway of farnesylated proteins.

The C-terminal "CaaX"-motif-containing proteins usually undergo three sequential post-translational processing steps: (1) attachment of a prenyl group to the cysteine residue; (2) proteolytic removal of the last three amino acids "aaX"; (3) methyl esterification of the exposed alpha-carboxyl group of the prenyl-cysteine residue. The Trypanosoma brucei and Leishmania major Ras converting enzyme 1 (RCE1) orthologs of 302 and 285 amino acids-proteins, respectively, have only 13-20% sequence identity to those from other species but contain the critical residues for the activity found in other orthologs. The Trypanosoma brucei a-factor converting enzyme 1 (AFC1) ortholog consists of 427 amino acids with 29-33% sequence identity to those of other species and contains the consensus HExxH zinc-binding motif.

Upregulation of sterol C14-demethylase expression in Trypanosoma cruzi treated with sterol biosynthesis inhibitors.

Infection with the protozoan, Trypanosoma cruzi, is the cause of Chagas disease that occurs widely throughout Latin America. T. cruzi contains sterol biosynthesis enzymes, and produces sterol products similar to those found in fungi.

Ultrasonic spectrum-analysis and neural-network classification as a basis for ultrasonic imaging to target brachytherapy of prostate cancer.

Conventional B-mode ultrasound is the standard means of imaging the prostate for guiding prostate biopsies and planning brachytherapy of prostate cancer. Yet B-mode images do not allow adequate visualization of cancerous lesions of the prostate. Ultrasonic tissue-typing imaging based on spectrum analysis of radiofrequency echo signals has shown promise for overcoming the limitations of B-mode imaging for visualizing prostate tumors.