Almost sure it's an elaborate hoax - those SEMs (bottom pics) look identical to red blood cells (google image: rbc sem) which the research paper doesn't even mention - that alone arouses suspicion. There's no functional reason for a bacterium to be that shape - they usually suffer more from a high surface area in the first place, which is what that shape creates.
Hoax papers get accepted by minor scientific journals surprisingly frequently (I remember one with 'dinosaurs' in the title!) as they don't have the money/inclination to peer review all the papers. Also, the focus that the 'particles' don't contain DNA is almost comic as 1. alien life forms certainly wouldn't have DNA like us and 2. RBCs don't have DNA... too good to be true!