Mechanism of butyl alcohol extract of Baitouweng Decoction (BAEB) on Candida albicans biofilms based on pH signal pathway / 中国中药杂志

This study aimed to investigate the effect of butyl alcohol extract of Baitouweng Decoction( BAEB) on Candida albicans biofilms based on pH signal pathway. The morphology of biofilms of the pH mutants was observed by scanning electron microscope. The biofilm thickness of the pH mutants was measured by CLSM. The biofilm activity of the pH mutants was analyzed by microplate reader.The biofilm damage of the pH mutants was detected by flow cytometry. The expression of pH mutant biofilm-related genes was detected by qRT-PCR. The results showed that the deletion of PHR1 gene resulted in the defect of biofilm,but there were more substrates for PHR1 complementation. BAEB had no significant effect on the two strains. RIM101 gene deletion or complementation did not cause significant structural damage,but after BAEB treatment,the biofilms of both strains were significantly inhibited. For the biofilm thickness,PHR1 deletion or complementation caused the thickness to decrease,after BAEB treatment,the thickness of the two strains did not change significantly. However,RIM101 gene deletion or complementation had little effect on the thickness,and the thickness of the two strains became thinner after adding BAEB. For biofilm activity,PHR1 deletion or complementation and RIM101 deletion resulted in decreased activity,RIM101 complementation did not change significantly; BAEB significantly inhibited biofilm activity of PHR1 deletion,PHR1 complemetation,RIM101 deletion and RIM101 complemetation strains. For the biofilm damage,PHR1 gene deletion or complementation,RIM101 gene deletion or complementation all showed different degrees of damage; after adding BAEB,the damage rate of PHR1 deletion or complementation was not significantly different,but the damage rate of RIM101 deletion or complementation was significantly increased. Except to the up-regulation of HSP90 gene expression,ALS3,SUN41,HWP1,UME6 and PGA10 genes of PHR1 deletion,PHR1 complementation,RIM101 deletion,and RIM101 complementation strains showed a downward expression trend. In a word,this study showed that mutations in PHR1 and RIM101 genes in the pH signaling pathway could enhance the sensitivity of the strains to the antifungal drug BAEB,thus inhibiting the biofilm formation and related genes expression in C. albicans.

The role of cell density in the morphology of the Candida albicans bioflims development and the tyrosol production / 中华微生物学和免疫学杂志

Objective To study the role of cell density in the tyrosol production and morphology for Candida albicans biofilms. Methods C. albicans SC5314 and clinical isolates were propagated in yeast peptone dextrose (YPD) medium. Cells were collected by centrifugation and washed twice in sterile phosphate-buffered saline (PBS) before this study, then resuspended in RPMI 1640 supplemented with L-glutamine and adjusted to a desired concentration of 5 × 10~6 cells/ml, 5×10~5 cells/ml, 5 × 10~4 cells/ml, 5 × 10~3 cells/ml after counting with a hematocytometer. Standardized C. albicans cells were prepared as above description and 2000 μl of this standardized cell suspension was dispensed into the wells, then C. albicans biofilms were formed on the bottom of the polystyrene wells. In this study, tyrosol synthesized by SC5314 and clinical isolates of C. albicans biofilm was quantified by high performance liquid chromatography (HPLC). The effects of tyrosol on morphology of C. albicans biofilms were investigated by scanning electron microscopy (SEM). Results Tyrosol production of C. albicans biofilms was affected by cell densities. At lower inoculation size(5 μ 10~3 cells/ml), there was too less tyrosol production to be detected at the early stage of the biofilms formation. At higher inoculation size (5 μ10~6 cells/ml), tyrosol can be detectable at the early stage or at the mature stage of biofilms formation. There was a sharp increase in tyrosol concentration at 24 h, while there was a decrease in tyrosol concentration after that time from the strains when the strains were at an inoculation size of 5 × 10~6 cells/ml and 5 × 10~5 cells/ml. Cell densities affected the morphology formation of the C. albicans biofilms. At the early stage of the biofilms formation, C. albicans grew less germ tube at lower cell densities than that at the higher cell densities. With the mature of the biofilms, C. albicarts grew more hyphae at higher cell densities than that at the lower cell densities. All these above showed that cell densities played an important role in the propagation for the C. albi-cans in the biofilm formation. Conclusion Cell density play an important role in the formation of the C. albi-cans biofilms and the production of the tyrosol.