RESUMO
The three-dimensional (3D) genome structure of an organism or cell is highly relevant to its biological activities, but the availability of 3D genome information for bacteria, especially intracellular pathogens, is still limited. Here, we used Hi-C (high-throughput chromosome conformation capture) technology to determine the 3D chromosome structures of exponential- and stationary-phase Brucella melitensis at a 1-kb resolution. We observed that the contact heat maps of the two B. melitensis chromosomes contain a prominent diagonal and a secondary diagonal. Then, 79 chromatin interaction domains (CIDs) were detected at an optical density at 600 nm (OD600) of 0.4 (exponential phase), with the longest CID being 106 kb and the shortest being 12 kb. Moreover, we obtained 49,363 significant cis-interaction loci and 59,953 significant trans-interaction loci. Meanwhile, 82 CIDs of B. melitensis at an OD600 of 1.5 (stationary phase) were detected, with the longest CID being 94 kb and the shortest being 16 kb. In addition, 25,965 significant cis-interaction loci and 35,938 significant trans-interaction loci were obtained in this phase. Furthermore, we found that as the B. melitensis cells grew from the logarithmic to the plateau phase, the frequency of short-range interactions increased, while that of long-range interactions decreased. Finally, combined analysis of 3D genome and whole-genome transcriptome (RNA-seq) data revealed that the strength of short-range interactions in Chr1 is specifically and strongly correlated with gene expression. Overall, our study provides a global view of the chromatin interactions in the B. melitensis chromosomes, which will serve as a resource for further study of the spatial regulation of gene expression in Brucella. IMPORTANCE The spatial structure of chromatin plays important roles in normal cell functions and in the regulation of gene expression. Three-dimensional genome sequencing has been performed in many mammals and plants, but the availability of such data for bacteria, especially intracellular pathogens, is still limited. Approximately 10% of sequenced bacterial genomes contain more than one replicon. However, how multiple replicons are organized within bacterial cells, how they interact, and whether these interactions help to maintain or segregate these multipartite genomes are unresolved issues. Brucella is a Gram-negative, facultative intracellular, and zoonotic bacterium. Except for Brucella suis biovar 3, Brucella species have two chromosomes. Here, we applied Hi-C technology to determine the 3D genome structures of exponential- and stationary-phase Brucella melitensis chromosomes at a 1-kb resolution. Combined analysis of the 3D genome and RNA-seq data indicated that the strength of short-range interactions in B. melitensis Chr1 is specifically and strongly correlated with gene expression. Our study provides a resource to achieve a deeper understanding of the spatial regulation of gene expression in Brucella.
RESUMO
PURPOSE: To compare the effectiveness of TiRobot-assisted kyphoplasty with that of the traditional fluoroscopy-assisted approach in treating multilevel osteoporotic vertebral compression fractures. METHODS: In this retrospective study, we collected data from 71 patients (TiRobot-assisted group, n = 39; fluoroscopy-assisted group, n = 32) with multilevel osteoporotic vertebral compression fracture treated with unilateral traditional TiRobot-assisted or fluoroscopy-assisted percutaneous kyphoplasty. The operative time, infusion volume, length of stay (LOS), hospital expenses, visual analog scale (VAS), Oswestry Disability Index (ODI), radiation exposure, puncture deviation, anterior height of diseased vertebrae, local kyphotic angle, bone cement distribution, and bone cement leakage were compared between the TiRobot- and fluoroscopy-assisted groups. RESULTS: Of the 257 treated vertebrae, the average amount of bone cement injected in the TiRobot-assisted (142 vertebrae) and fluoroscopy-assisted (115 vertebrae) groups was 4.6 mL and 4.5 mL, respectively. The VAS score was significantly lower in the TiRobot-assisted group at 24 hours post-operatively (p = 0.006). The X-ray frequency was 34.7 times in the TiRobot-assisted group and 51.7 times in the fluoroscopy-assisted group (p < 0.001). In addition to the operative time, cumulative radiation dose for the surgeon and patient was significantly lower in the TiRobot-assisted group. The hospital expenses of the TiRobot-assisted group were significantly higher (p < 0.001). The puncture deviation and bone cement distribution were better in the TiRobot-assisted group (p < 0.001). Bone cement leakage was found in 18 and 29 cases in the TiRobot- and fluoroscopy-assisted groups, respectively (p = 0.010). One patient in the fluoroscopy-assisted group experienced radiculopathy due to a misplaced puncture but recovered in three months. No radiculopathy was observed in the TiRobot-assisted group. CONCLUSIONS: TiRobot-assisted percutaneous multilevel kyphoplasty is more accurate and has smaller radiometry, a more uniform bone cement distribution, and lower bone cement leakage. This method was therefore accurate and safe.
