Fig. 5

Distinct patterns were observed for pangolin sperm acrosome and tail tyrosine phosphorylation status. a Dynamic rearrangement of sperm acrosome can be observed when mouse and chimpanzee (represent primate species) sperm cells were incubated in defined stimulation media, at these defined media, sperm capacitation and acrosome reaction can be induced and sperm acrosome (indicated with arrowheads) and its integrity can be observed by acrosome specific PNA staining. b Three distinct acrosome patterns were detected likely represent intact inactive sperm (left panel), acrosome reacting sperm (middle panel) and acrosome reacted sperm (right panel) as triangle-shaped, aggregated punctuated and weak diffused PNA stain were observed (marked with arrowheads). Moreover, rearrangement of sperm acrosome from the apical tip toward the edge of sperm head (marked with arrows) was also observed when aggregated punctuated PNA stain (marked with asterisks, inset image) was detected. c Increase protein tyrosine phosphorylation can be observed at sperm tail when mouse and chimpanzee (represent primate species) sperm cells were incubated in capacitation media. d Two distinct patterns when anti-phosphotyrosine antibody was used to demonstrate protein tyrosine phosphorylation status of pangolin sperm. The first pattern showed no detection of signal at the sperm tail with homogenous PNA staining pattern (in green) present at the sperm head (left panel); another pattern showed strong signal throughout sperm mid-piece and sperm tail (in red) with PNA stain aggregated as punctuated signal at the tip of sperm head (in green, marked with asterisks). Moreover, we detected PNA signal occasionally present at the sperm mid-piece overlapping with phosphotyrosine signal