Figure 1.
Effect of H2S on A. niger and P. italicum growth in inoculated fruits and on defined media.
A, photographs of six kinds of postharvest fruits inoculated with A. niger and P. italicum when fumigated with 0.0 mM (control) or 0.5 mM NaHS solution for 9 d at 25°C; B, photographs of A. niger and P. italicum grown on Petri plates on defined media after fumigation with 0.00, 0.01, 0.05, 0.10, 0.50 and 2.50 mM NaHS solutions for 2 d at 25°C; C, photographs of A. niger and P. italicum after 1 d of 2.5 mM NaHS treatment and recovered in water fumigation for another 8 d at 25°C.
Table 1.
Colony diameter of A. niger and P. italicum after exposure to H2S at 25°C.
Table 2.
Spore germination and germ tube elongation of A. niger and P. italicum after exposure to H2S at 25°C.
Figure 2.
Effect of H2S fumigation on mycelial growth and micro-morphology of A. niger and P. italicum grown on defined media.
Colonies were cultured for 3°C, and then exposed to H2S released from 0.5 mM and 2.5 mM NaHS for 1 d. A and B, mycelial growth and micro-morphology of A. niger; C and D, mycelial growth and micro-morphology of P. italicum.
Figure 3.
Effect of H2S fumigation on ROS level in A. niger.
A. niger cells in Figure 2 were used for ROS detection. A, ROS staining in sporangia and sporangiophores; B, ROS staining in A. niger spores. Left parts of A and B shows the bright field images, and right parts fluorescence images.
Figure 4.
Effect of H2S fumigation on enzyme activities and gene expression of SOD and CAT in A. niger.
Colonies were cultured for 3°C, and then exposed to H2S released from 0.5 mM and 2.5 mM NaHS for 1 d. A, SOD activity in A. niger; B, CAT activity in A. niger; C, RT-PCR results to analyze gene expressions of SOD and CAT in A. niger. D, relative expression levels by quantifying RT-PCR results in C (with the actin-encoding gene value [ANI_1_106134] set as 1.0) with Image J software. Different letters mean significance of difference between the treatments (P<0.01, ANOVA, LSD).
Figure 5.
Effect of H2S fumigation on grown of baker's yeast, C. albicans, R. oryzae, and some food-borne bacteria growth on defined media.
A–F, photographs of S. cerevisiae, S. aureus, S. typhimurium, L. monocytogenes, B. subtilis and B. thuringiensis after 3 d exposure to H2S released from different concentrations of NaHS at 25°C; G–H, photographs of E. coli and E. aerogenes after exposure to H2S for 1 d; I–J, photographs of C. albicans and R. oryzae after exposure to H2S for 4 d and 7 d, respectively.
Figure 6.
Effect of short term H2S exposure to baker's yeast, C. albicans, R. oryzae, and some food-borne bacteria grown on defined media.
After 1°C, the photographs were taken. A–H show photographs of S. cerevisiae, S. aureus, S. typhimurium, L. monocytogenes, B. subtilis, B. thuringiensis, E. coli and E. aerogenes, respectively; I–J show photographs of C. albicans and R. oryzae recovered in water atmosphere for 2 and 4 d after 2.5 mM NaHS treatment for 1 d.
Table 3.
Colony formation of yeasts and bacteria after exposure to H2S at 25°C.