Even when a field isolates, the higher passage ureaplasma may not lose or change yet the genetic expression for the studied invasion. In fact these mollicutes are few studied and quite different, therefore, they may reveal additional features for these bacteria. Buim (unpublished data) observed that the high (WVU 1853) and low passage isolates (MS1 and MS2) of M. synoviae also showed similar adhesion and invasion into Hep-2 cells and similarly surrounded the nucleus. Ueno et al. [18] observed the same results with

high and low passages of M. genitallium infecting HeLa and endometrial human cells. In this study, both ureaplasma reference strains and clinical isolates were detected inside the cells similarly surrounding the perinuclear

regions but not inside the nucleus. The perinuclear Selleckchem NCT-501 arrangement was observed in other mollicutes [9, 15, 16]. Nevertheless, Ueno et al. [18] detected M. genitalium inside the nucleus after 30 minutes infection. Meseguer et al. [19] observed abnormal fluorescence in nuclear images in infected cultures, but failed to confirm the location of M. pneumonie. The invasion of mollicutes is not completely established and different mechanisms have been proposed based on the studied mollicute and infected cells. Yavlovich et al. [20, 21] showed the dependence of plasminogen-Pg in the invasion process of M. fermentans MF. Proteases inhibitor The Pg Ferrostatin-1 chemical structure treated MF were able to invade HeLa cells in three hours, but not the untreated MF. The phospholipase C (PLC) is detected in many walled bacteria and is considered a virulence factor for tissue damage. In some mollicutes, PLC was detected [22] and associated with the cell invasion due to membrane and cytoskeleton modification. The mycoplasmal PLC was also associated with a host cell signal transduction cascade and the rearrangement of host cytoskeletal components [2, 22]. The invading mycoplasmas generate uptake signals that trigger the assembly of highly organized cytoskeletal structures in the host cells. The invasion of M. penetrans is associated with tyrosine phosphorylation of a 145-kDa host cell protein that activate PLC

to generate two additional messengers: phosphatidylinositol metabolites and diacylglycerol [23]. These observations support the hypothesis that Lck M. penetrans use phospholipase to cleave membrane phospholipids, thereby initiating the signal transduction cascade. Moreover, the PLC appears to play a role in the escape from the primary vacuole and in gaining access to the cytoplasm [24]. Listeria monocytogenes deficient in PLC are 500-fold less virulent in mice [25]. The studied ureaplasma showed a high PLC activity, without differences between the reference strains and the clinical isolates. This activity explains similar behavior in Hep-2 cells and suggests the role of PLC as a factor for invasion of ureaplasma. Conclusions The biological consequences of mycoplasma invasion are not established.