Fig. 1

Morphologies of honokiol-treated Cryptocaryon irritans tomonts stained and unstained with Annexin V-FITC/PI. The C. irritans tomonts were treated with honokiol at 0.0, 0.6, 1.0, 2.0, 4.0, and 8.0 μg/ml for 8 h. The treated tomonts were incubated with Annexin V-FITC and a PI probe and observed under a fluorescence inversion microscope (DMi8 + DFC7000T, Leica Microsystems, Germany). The results show that all the honokiol-treated C. irritans tomonts’ cytoplasms obviously shrank and were stained with Annexin V-FITC. When the concentration of honokiol was > 4.0 μg/ml, the treated C. irritans tomonts’ cytoplasms were irregularly condensed, became hyaline, and were stained by PI. a–f: Morphologies of C. irritans tomonts respectively treated with 0.0, 0.6, 1.0, 2.0, 4.0, and 8.0 μg/ml honokiol for 8 h. g–l: Morphologies of C. irritans tomonts respectively treated with 0.0, 0.6, 1.0, 2.0, 4.0, and 8.0 μg/ml honokiol for 8 h and observed at Ex/Em = 488/525 nm. m–r: Morphologies of C. irritans tomonts respectively treated with 0.0, 0.6, 1.0, 2.0, 4.0, and 8.0 μg/ml honokiol for 8 h and observed at Ex/Em = 488/630 nm. s–x: Overlapping morphology photos of C. irritans tomonts respectively treated with 0.0, 0.6, 1.0, 2.0, 4.0, and 8.0 μg/ml honokiol for 8 h and recorded at Ex/Em = 488/525 nm and Ex/Em = 488/630 nm. All bars = 300 μm