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A fluorescent method for monitoring the activity of the secreted Candida carboxyl (aspartic) proteinase (EC 3.4.23.6) was developed using a fluorogenic substrate based on resonance energy transfer. The fluorescent assay was used to monitor proteinase production, purification, and inhibition. The Km for the fluorogenic substrate,(More)
Formation of branched glucan, glucan-glucan cross links, and glucan-chitin cross links most likely involves the action of fungal wall glucanases and transglycosylases. We developed an HPLC assay using radiolabeled substrates in order to study the kinetics of interaction of donor and acceptor molecules with a glucosyltransferase present in the cell walls of(More)
A systematic evaluation of the in vitro (1,3)-beta-glucan synthase assay parameters was performed using microsomes prepared from Candida albicans from either yeast or mycelial phase cells. Enzyme activities of both yeast and mycelial phase microsomes depended on the presence of guanosine-5'-O-(3-thiophosphate) and either bovine serum albumin or a detergent(More)
The design, synthesis and in vitro biological evaluation of pyridinium ion based inhibitors of oxidosqualene cyclase enzymes are reported. N-Alkyl- and N-prenylpyridinium ions have been found to be potent and specific inhibitors of Candida albicans oxidosqualene-lanosterol cyclase and to exhibit antifungal activity. The ability of pyridinium ions to inhibit(More)
One major mechanism for resistance to macrolide antibiotics in Streptococcus pneumoniae is MLS (macrolide, lincosamide, and streptogramin B) resistance, manifested when the 23S rRNA is methylated by the product of an erm gene. This modification results in the decreased binding of all known macrolide, lincosamide, and streptogramin B antibiotics to the(More)
The incidence of severe, life-threatening fungal infections has increased dramatically over the last decade. Unfortunately, in practice the arsenal of antifungal drugs is limited to flucytosine, a few approved azoles, and polyenes, mainly amphotericin B. This situation is rather precarious in view of the extended spectrum of fungi causing severe disease in(More)
Clarithromycin, the 6-O-methyl derivative of erythromycin, is approved for treatment of Mycobacterium avium infections and for prophylaxis in patients at risk. Since clarithromycin is more active against mycobacteria than the parent compound, erythromycin, we evaluated the interaction of erythromycin and clarithromycin with cells and ribosomes isolated from(More)
Yeast and other fungi contain a soluble elongation factor 3 (EF-3) which is required for growth and protein synthesis. EF-3 contains two ABC cassettes, and binds and hydrolyses ATP. We identified a homolog of the YEF3 gene in the Saccharomyces cerevisiae genome database. This gene, designated YEF3B, is 84% identical in protein sequence to YEF3, which we(More)
Cispentacin tranport into Candida albicans CCH442 was via a specific inducible proline permease and other amino acid permeases. Drug entry was also dependent upon the proton motive force. The apparent Km and Vmax for drug uptake under induced conditions were 0.4 mM and 7 nmol/microliter/min, respectively, with cellular accumulation in the mM range.(More)
Macrolide resistance in Streptococcus pneumoniae has been associated with two main mechanisms: target modification by Erm methyltransferases and efflux by macrolide pumps. The ketolide ABT-773, which has a 3-keto group and no L-cladinose sugar, represents a new class of drugs with in vitro activity against a variety of resistant bacteria. Several approaches(More)