Enhanced germination rate of B. cereus spores germinated in conditioned supernatants.

<p>Wild-type <i>B. cereus</i> spores were germinated with a 0.2 mM inosine solution (•) or in conditioned supernatants containing 0.2 mM inosine (▪). <i>B. cereus</i> spores were also germinated with 0.2 mM inosine and 20 µM alanine (X).</p

<i>B. cereus</i> spore germination at low spore concentrations.

<p>(A) <i>B. cereus</i> spores were diluted in 10 or 4000 ml (OD₅₈₀ of 1 or 0.0025, respectively) of germination buffer supplemented with 0.2 mM inosine and 0 or 40 µM alanine. Thirty min post-inosine exposure, spores were collected by centrifugation, and pellets were treated with malachite green to stain resting spores and safranin-O to stain germinated cells. Samples were placed under a microscope and a field selected at random. (B) <i>B. cereus</i> spores were diluted in germination buffer (OD₅₈₀ of 1 to 0.0025) in the presence of 0.2 mM inosine. Stained samples were placed under a light microscope and the amount of resting spores and germinated cells were counted on three different fields selected at random. The percentage of germinated spores was plotted against the initial spore optical density.</p

7-AMC adducts detected in <i>wt B. cereus</i> conditioned supernatants.

<p>Wild type <i>B. cereus</i> 569 spores were resuspended in 200 µl TMB buffer to OD₅₈₀ = 1. Spores were treated with 0.2 mM inosine and supernatants were collected 30 min post-inosine addition. Collected supernatants were labeled with 7-AMC. 7-AMC adducts sere separated by RP-HPLC and identified by mass spectrometry. Concentrations were calculated by fluorescence spectroscopy.</p

<i>B. cereus</i> spore germination in the presence of Ca-DPA.

<p>(A) Wild-type <i>B. cereus</i> spores were germinated in the presence of 0.2 mM inosine (□). <i>B. cereus</i> spores were also germinated in the presence of conditioned supernatants containing 0.2 mM inosine (+). Spores were also germinated with 0.2 mM inosine supplemented with 0.18 mM Ca-DPA (▪).</p