This study was aimed to explore the features of clustered regularly interspaced short palindromic repeats (CRISPR) structures in Shigella by using bioinformatics. We used bioinformatics methods, including BLAST, alignment and RNA structure prediction, to analyze the CRISPR structures of Shigella genomes. The results showed that the CRISPRs existed in the four groups of Shigella, and the flanking sequences of upstream CRISPRs could be classified into the same group with those of the downstream. We also found some relatively conserved palindromic motifs in the leader sequences. Repeat sequences had the same group with corresponding flanking sequences, and could be classified into two different types by their RNA secondary structures, which contain "stem" and "ring". Some spacers were found to homologize with part sequences of plasmids or phages. The study indicated that there were correlations between repeat sequences and flanking sequences, and the repeats might act as a kind of recognition mechanism to mediate the interaction between foreign genetic elements and Cas proteins.
ObjectiveTo provide the anatomical basis for the selection of osteotomy site in leg lengthening or tibial slip. MethodsBetween August 2010 and July 2014, 10 adult fresh amputated leg specimens were collected. The pressure perfusion of red latex was performed by the popliteal artery. The anterior tibial artery and its main branches were separated and exposed, and the periosteal branch of anterior tibial artery was adequately exposed;the posterior tibial artery and its main branches were exposed;the peroneal artery was separated and exposed. The tibial and peroneal artery and its branches were observed and measured. When measuring the proximal end, the medial tibial plateau bone margin, the most prominent part of the tibial tuberosity, and the fibular head edge were used as a reference;when measuring the distal end, distal medial condyle of tibia malleolus tip, tibial lateral malleolus lateral tip, and distal tibial articular surface were used as a reference;the vertical distance between tibia proximal and distal main arteries and bone end reference was measured to determine the optimal osteotomy position of upper and lower tibia. The osteotomy index was calculated which was used to represent the relative position of osteotomy site in the whole tibia. ResultsThe proximal tibial osteotomy site located at (78.2±19.5) mm from medial tibial plateau margin, (41.8±16.0) mm from the tibial tuberosity pole, and (66.7±16.4) mm from the fibular head edge. The distal tibial osteotomy site located at (70.8±12.1) mm above the inferior margin of tibial medial malleolus, (83.3±13.0) mm above the inferior margin of lateral malleolus tip, and (59.1±11.7) mm from distal tibial articular surface. The proximal tibial osteotomy index was 18.45-23.35 (mean, 20.46);the distal tibial osteotomy index was 14.36-23.05 (mean, 18.81). ConclusionThe metaphyseal-diaphyseal connection shold be selected in the proximal and distal tibia osteotomy, the lower one third of the tibia is not suitable for ostetomy.