N-terminus GTPase domain of the cytoskeleton protein FtsZ plays a critical role in its adaptation to high hydrostatic pressure.

Studies in model microorganisms showed that cell division is highly vulnerable to high hydrostatic pressure (HHP). Disassembly of FtsZ filaments induced by HHP results in the failure of cell division and formation of filamentous cells in E. coli. The specific characteristics of FtsZ that allow for functional cell division in the deep-sea environments, especially in obligate piezophiles that grow exclusively under HHP condition, remain enigmatic. In this study, by using a self-developed HHP in-situ fixation apparatus, we investigated the effect of HHP on FtsZ by examining the subcellular localization of GFP-tagged FtsZ in vivo and the stability of FtsZ filament in vitro. We compared the pressure tolerance of FtsZ proteins from pressure-sensitive strain Shewanella oneidensis MR-1 (FtsZSo) and obligately piezophilic strain Shewanella benthica DB21MT-2 (FtsZSb). Our findings showed that, unlike FtsZSo, HHP hardly affected the Z-ring formation of FtsZSb, and filaments composed of FtsZSb were more stable after incubation under 50 MPa. By constructing chimeric and single amino acid mutated FtsZ proteins, we identified five residues in the N-terminal GTPase domain of FtsZSb whose mutation would impair the Z-ring formation under HHP conditions. Overall, these results demonstrate that FtsZ from the obligately piezophilic strain exhibits superior pressure tolerance than its homologue from shallow water species, both in vivo and in vitro. Differences in pressure tolerance of FtsZ are largely attributed to the N-terminal GTPase domain. This represents the first in-depth study of the adaptation of microbial cytoskeleton protein FtsZ to high hydrostatic pressure, which may provide insights into understanding the complex bioprocess of cell division under extreme environments.

Robot-assisted versus stereotactic frame-based stereoelectroencephalography in medically refractory epilepsy.

AIM: To explore the difference between robot assisted (RA) and stereotactic frame based (SF) stereoelectroencephalography (SEEG) in patients with medically refractory epilepsy. METHODS: We undertook a retrospective review of 33 SEEG cases at our center, of which 14 were SF performed from March to October 2018 and 19 were RA performed from November 2018 to December 2019. Detailed review of medical histories and operative records as well as imaging and trajectory plans was carried out for each patient, and the results related to each technique compared. A multiple linear regression model was used to test for variables that significantly influenced placement error. RESULTS: Compared to the SF group, the RA group had a higher mean number of electrodes per patient (10.7 ±â€¯2.8 versus 6.4 ±â€¯0.8, P < 0.0001) and a significantly shorter mean operative time (127.3 ±â€¯40.7 versus 152.7 ±â€¯13.6 min, P = 0.033). For the RA group, the intracranial implantation length was positively correlated with target point error (p = 0.000), depth error (p = 0.043), and two-dimensional (2D) radial error (p = 0.041). Conversely, skull thickness was negatively correlated with the TP error (p = 0.004), depth error (p = 0.037) and 2D radial error (p = 0.000). We also analyzed the mean entry point, target point, depth and 2D radial errors, the complication rates, and the results of epileptogenic zone (EZ) localization and Engel class. The results showed no difference in these aspects between the SF group and the RA group. CONCLUSION: This study suggests that, compared to stereotactic frame based SEEG, robot assisted SEEG is significantly more efficient and comparable in safety and effectiveness.