13r1), yielding a range of spring constants from 0.03 to 0.06 (N/m). Statistics Typically, measured bacterial adhesion forces contained a large spread and were not normally distributed (Geneticin solubility dmso Shapiro–Wilk test, P < 0.01). Hence, S63845 chemical structure data are presented as median and interquartile range. Adhesion forces for different fungus-bacterium pairs were compared using non-parametric analyses (Mann–Whitney test). Differences were considered significant when the P-value was < 0.05. Results Adhesion of staphylococci to hyphae and yeast cells using fluorescence microscopy In order to assess

the adhesion of S. aureus NCTC8325-4GFP along the length of C. albicans hyphae, we used two different fungal strains: C. albicans SC5314 and C. albicans MB1. Bacterial adhesion to hyphae was visualized with fluorescent microscopy and quantitated by enumeration of adhering bacteria per unit hyphal length (Figure 2). Most bacteria adhered to the tip and middle regions of the hyphae and adhered only scarcely to the head region of the hyphae or to non-germinating yeast cells (Figure 2C). Note that strictly speaking, a comparison of the number of staphylococci

adhering per unit hyphal length may not be directly compared with the number of bacteria adhering to a non-germinating yeast cell. Both C. albicans strains showed the same trend, although bacteria adhered to C. albicans SC5314 in higher numbers than to the clinical isolate MB1. Figure 2 Microscopic analysis see more of inter-species interaction. Examples of fluorescent microscopic images and quantitative enumeration of the interaction between S. aureus NCTC8325-4GFP and C. albicans strains. (A) S. aureus with C. albicans SC5314 hyphae. (B) S. aureus with C. albicans MB1 hyphae. Scale bar corresponds with 10 μm. (C) number of S. aureus NCTC8325-4GFP adhering per 10 μm length of different regions of C. albicans hyphae and Phosphatidylinositol diacylglycerol-lyase yeast cells. Error bars represent SD over three experiments with separately cultured organisms and involving 30 hyphae per bacterium-fungus pair. Adhesion force along the hyphae using atomic force microscopy Adhesion forces between S. aureus NCTC8325-4GFP and both

C. albicans strains along the hyphae were determined using AFM (Figure 1). Figure 3 shows typical examples of force-distance curves of the S. aureus probe upon approach and retract from C. albicans hyphae and yeast surfaces at initial contact and after 60 s surface delay. Major differences existed in AFM force-distance curves recorded immediately upon contact (0 s) and after a 60 s surface delay between S. aureus NCTC8325-4GFP and different hyphal regions and the yeast cell, as summarized in Figure 4. In line with the higher number of bacteria adhering to the tip and middle regions of C. albicans hyphae (Figure 2C), stronger adhesion forces (around 4 nN for SC5314 and around 2 nN for MB1) were recorded after bond-maturation between these regions than for the head regions (around 0.5 nN). However, adhesion forces measured between S.