Amphotericin-B-mediated reactivation of latent HIV-1 infection[J].
Renal effects of amphotericin B lipid complex[J].
Since deletion of only two genes in the sphingolipid biosynthetic pathway sensitized cells to AmB, we tested the effects on AmB resistance of chemical inhibition of sphingolipid biosynthesis in wild-type strains. Myriocin is a specific inhibitor of serine palmitoyltransferase encoded by the essential genes LCB1 and LCB2, which catalyze the first committed step of sphingolipid biosynthesis (, ). We incubated C. albicans (SC5314), C. glabrata (CG462), C. lusitaniae (CL1 and CL6), and S. cerevisiae (FY4 and BY4743) strains at different concentrations of AmB and myriocin, alone and in combination. Myriocin at a sublethal concentration (0.4 μg/ml) rendered the cells sensitive to sublethal concentrations of AmB (0.1 μg/ml for C. albicans, S. cerevisiae, and C. lusitaniae strain CL1 and 0.25 μg/ml for C. glabrata and C. lusitaniae strain CL6), indicating that inhibition of sphingolipid biosynthesis sensitizes cells to AmB (). To quantitate this, a checkerboard broth microdilution assay using a CLSI standard reference method () was used. Myriocin sensitized cells to AmB by 4- to 8-fold and was synergistic with AmB for all the tested strains, with a fractional inhibitory concentration (FIC) index of ). However, the synergistic effect of myriocin remains to be verified with other pathogenic Candida species. To confirm if AmB sensitivity is due to depletion of sphingolipids, we supplemented AmB-myriocin plates with a sublethal concentration (10 μM) of phytosphingosine (PHS). PHS is an intermediate downstream of serine palmitoyltransferase in sphingolipid biosynthesis, and it is known to rescue myriocin inhibition of sphingolipid biosynthesis (). We found that PHS reversed the AmB sensitivity of myriocin-treated cells, confirming the role of sphingolipids in AmB resistance ().
Biosynthesis of amphotericin B[J].
In recent years, with the development of AmB derivatives, the analysis of genome of the and the metabolic pathways of AmB, more and more strategies involving genetic engineering and metabolic engineering were used to study the combinatorial biosynthesis of AmB.