Current methods for photodynamic therapy in the US: comparison of MAL/PDT and ALA/PDT.

There is some debate regarding the rate of progression of actinic keratosis (AK) into squamous cell carcinoma (SCC).1-4 However, it is clear that treatment for AK lesions is warranted. Results from numerous studies with aminolevulinic acid (ALA) and methyl aminolevulinate (MAL) photodynamic therapy (PDT) for the treatment of AKs, SCC, and Bowen's disease show high rates of clearance for these lesions.

Expression and degradation of the cystic fibrosis transmembrane conductance regulator in Saccharomyces cerevisiae.

Many cystic fibrosis disease-associated mutations cause a defect in the biosynthetic processing and trafficking of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Yeast mutants, defective at various steps of the secretory pathway, have been used to dissect the mechanisms of biosynthetic processing and intracellular transport of several proteins. To exploit these yeast mutants, we have employed an expression system in which the CFTR gene is driven by the promoter of a structurally related yeast ABC protein, Pdr5p.

Intragenic suppressors of an OmpF assembly mutant and assessment of the roles of various OmpF residues in assembly through informational suppressors.

We employed two separate genetic approaches to examine the roles of various OmpF residues in assembly. In one approach, intragenic suppressors of a temperature-sensitive OmpF assembly mutant carrying a W214E substitution were sought at 42 degrees C, or at 37 degrees C in a genetic background lacking the periplasmic folding factor SurA. In the majority of cases (58 out of 61 revertants), the suppressors mapped either at the original site (position 214) or two residues downstream from it.

Modulations in lipid A and phospholipid biosynthesis pathways influence outer membrane protein assembly in Escherichia coli K-12.

The assembly defect of a mutant outer membrane protein, OmpF315, can be corrected by suppressor mutations that lower lipopolysaccharide (LPS) levels and indirectly elevate phospholipid levels. One such assembly suppressor mutation, asmB1, is an allele of lpxC (envA) whose product catalyses the first rate-limiting step in the lipid A (LPS) biosynthesis pathway. Besides reducing LPS levels, asmB1 confers sensitivity to MacConkey medium.