Lysis is a common functional module in synthetic biology and is widely used in genetic circuit design. Lysis could be achieved by inducing expression of lysis cassettes originated from phages. However, detailed characterization of lysis cassettes hasn't been reported yet. Here, we first adopted arabinose- and rhamnose-inducible systems to develop inducible expression of five lysis cassettes (S₁₀₅, A52G, C51S S76C, LKD, LUZ) in Escherichia coli Top10. By measuring OD₆₀₀, we characterized the lysis behavior of strains harboring different lysis cassettes. These strains were harvested at different growth stages, induced with different concentrations of chemical inducers, or contained plasmids with different copy numbers. We found that although all five lysis cassettes could induce bacterial lysis in Top10, lysis behaviors differed a lot at various conditions. We further found that due to the difference in background expression levels between strain Top10 and Pseudomonas aeruginosa PAO1, it was hard to construct inducible lysis systems in strain PAO1. The lysis cassette controlled by rhamnose-inducible system was finally inserted into the chromosome of strain PAO1 to construct lysis strains after careful screen. The results indicated that LUZ and LKD were more effective in strain PAO1 than S₁₀₅, A52G and C51S S76C. At last, we constructed an engineered bacteria Q16 using an optogenetic module BphS and the lysis cassette LUZ. The engineered strain was capable of adhering to target surface and achieving light-induced lysis by tuning the strength of ribosome binding sites (RBSs), showing great potential in surface modification.
Rhamnose/pharmacology* ; Plasmids/genetics* ; Pseudomonas aeruginosa ; Escherichia coli/metabolism*

During the teaching activities, to stimulate students' subject awareness and encour-age them to play the main role in class activities are inevitable trends in the reform of college educa-tion. Students’ subjective activity is a key to the teaching effect of regional anatomy, a course mainly based on experimental program. Department of Human Anatomy in Chongqing Medical University lay-outs regional anatomy teaching program to develop the students' subjective activities in learning from the course specialty: in preview and review, to train students' image-thinking by drawing; in anatomi-cal operation link, to cultivate students' interest in learning and innovation by discussing the relation-ship of anatomical structure and clinical disease and identifying the variation of structure; in the eval-uation process, taking the formative evaluation system to promote the students' initiatives and ensure the objectiveness and fairness. The implementation of these measures promotes the regional anatomy teaching quality.

China ; Humans ; Streptococcus pneumoniae

Objective To explore the relationship between the gait behavior changes and cognitive function in APP/PS1 transgenic mice .Methods 16 APP/PS1 transgenic mice were divided into model group and Huperzine A group, C57/BL6J mice with the same age were chosed as control group .After a 150 days consecutive treatment , Morris water maze(MWM) was used to detect the learning and memory ability and Gait analysis system (GAS-2) was used to detect the gait behavior after the treatment when the mice were 8-month-old.Results The escape latency of the model group was significantly higher than that of the control group ( P <0.05 ) , the time spended in the target quadrant , swimming distance in the target quadrant significantly lower than that of the control group ( P <0.05 ) , the first time passing through the platform prolonged significantly than the control group (P <0.05), and the number of passing though the platform reduced significantly than the control group (P <0.05).In the gait behavior experiments , compared with the control group, the average walking speed of the model group reduced significantly (P <0.05), the average walking cycle, the absolute average body angle and lateral movement increased significantly (P <0.05);The percentage of support time in a walking cycle of the left and right foot increased significantly (P <0.05).Accordingly, the percentage of swing time in a walking cycle of the left and right foot reduced significantly (P <0.05).The propulsion index of the left hand , right hand, right foot increased significantly ( P <0.05), and then the braking index of the above three feet decreased significantly ( P <0.05) .Huperzine A can improve the cognitive function , rectify the changes in the gait behavior .The two behavioral relevance shows that cognitive function and the front two feet braking , propulsion index have a high correlation index (correlation coefficients were -0.433, -0.379, P values were 0.039,0.079), the others were not. Conclusion APP/PS1 transgenic mice of 8-months-old have a remarkable impairment of learning and memory ability and disorder of gait behavior , and these two behaviors have a correlation in some extent .

The finite element model of the intact lumbar spine (L1-L5) was set up to study the biomechanical changes of three different pairs of the lumbar laminectomy. The three-dimensional finite elements model of L1-L5 vertebrae structure was constructed by the combination of self-compiled software and Hyper Mesh. The finite element model was compared with the experimental data in vitro. The finite element model was modified of stenosis at L3-L4 and L4-L5 with the same boundary conditions and physical loads to study the motion and loading in the annulus changes at the surgical site as a result of surgical alteration. The study suggested that the removal of posterior lumbar spinal elements for the treatment of stenosis at L3-L4 and L4-L5 produced a graded increase in motion at the surgical site, with the greatest changes occurring in flexion-extension and axial rotation and that during lateral bending the amount of resection was only slightly affected. The data showed that for flexion-extension and axial rotation the increases in motion were correlated to the extent of posterior element removal. It is necessary to retain the greatest degree of posterior lumbar structures in thorough decompression, which can further reduce the postoperative intervertebral disc, facet degeneration.
Adult ; Biomechanical Phenomena ; Computer Simulation ; Finite Element Analysis ; Humans ; Laminectomy ; methods ; Lumbar Vertebrae ; diagnostic imaging ; surgery ; Male ; Models, Biological ; Spinal Stenosis ; diagnostic imaging ; surgery ; Tomography, Spiral Computed

Objective To study the protective role of pre-resolving mediator lipoxin A4(LXA4) in the NA+ -K+-ATPase in alveolar type Ⅱ (AT Ⅱ ) epithelial cells of rats exposed to lipopolysaccharide (LPS). Method The AT Ⅱ cells were isolated and purified, and divided randomly into control group (PBS), vehiculum (alcohol 0.7 μL/mL) group, LPS (1 μg/mL) group, LXA4(1/10 mol/mL) group and LPS (1 μg/mL LPS) + LXA4(1/10 mol/mL) group. After exposure to LPS and/or LXA4 for4 hours, NA+-K+ -ATPase and β1-subunits mRNA in AT Ⅱ epithelial cells were detected by using RT-PCR, and ATP, ADP, AMP, total adenine nucleotides (TAN) and energy charge (EC) were measured by using high performance liquid chromatography (HPLC), and then the activities of Na+-K+-ATPase were calculated accordingly. Results The NA+-K+-ATPase α-subunit and β-subunit mRNA were significantly decreased in LPS group ( P ＜ 0.05 vs. control group). However, the expressions of NA+ -K+-ATPase mRNA were significantly enhanced by application of LXA4 to AT Ⅱ epithelial cells exposed to LPS (P ＜0.05 vs. LPS group). The activities of NA+ -K+ -ATPase were enhanced in LPS group (P ＜0.05 vs. control group). Compared with control group and LPS group, the activities of NA+-K+-ATpase in LPS + LXA4 group were significantly increased (P ＜0.01 vs. control group; P ＜0.05 vs. LPS group). The EC of AT Ⅱ epithelial cells were higher in LPS group ( P ＜ 0.01 vs. control group). There were no significant differences in EC between control group and LPS + LXA4group(P ＞0.05). Conclusions The pro-resolving mediator LXA4 can enhance the expressions of NA + -K + -ATPase α-subunit and β-subunit mRNA, and the activities of NA + -K + -ATPase in AT Ⅱ epithelial cells or rats exposed to LPS, and ca also balance the metabolism of AT Ⅱ epithelial cells. These findings suggest that LXA4 plays an important role in lung edema clearance in lung injury induced by endotoxin, and the role is likely associated with the enhancement of the expressions of Na+ -K+ -AT-Pase α-subunit and β-subunit, and the activities of Na+ -K* -ATPase, maintaining the balance of metabolism of AT Ⅱ epithelial cells.

Objective To investigate the effects of different doses of ulinastatin on severe thermal injuryinduced myocardial damage in rats. Methods One hundred and eighty female SD rats weighing 180-220 g were usedin this study. Thirty percent of the total body surface (TBS) was shaved chemically with 20% sodium sulphate and then exposed to 92 ℃ water for 18 s. The animals with third degree thermal injury involving 30% of the TBS were randomly divided into 3 groups (n = 60 each): group Ⅰ thermal injury (group TI); group Ⅱ and Ⅲ received intraperitoneal ulinastatin 40 000 and 80 000 U/kg respectively immediately after thermal injury (group U1 , U2). The TI group received equal volume of normal saline IP instead of ulinastatin. Blood samples were taken from abdominal aorta before (baseline) and at 1, 3, 6, 12 h after thermal injury for determination of serum concentrations of cTnI, IL-1β, IL-6, IL-10 and TNF-α (10 samples at each time points). Ten animals were sacrificed at each time point after blood sampling. The myocardial specimens were obtained for microscopic examination and measurement of MDA content and SOD activity. Results Compared with group TI, the serum concentrations of cTnI, IL-1β, IL-6 and TNF-α and MDA content in myocardium were significantly decreased and the myocardial SOD activity was significantly increased in group U1 , while in group U2 the senum concentrations of cTnI, IL-Iβ, IL-6 and TNF-α and myocardial MDA content were significantly increased and the myocardial SOD activity was significantly decreased. There was no siginificant difference in the serum concentrations of IL-10 among the three groups. Microscopic examination showed that myocardial damage was accentuated in group U2 as compared with group U1. Conclusion Ulinastatin 40 000 U/kg can ameliorate severe thermal injury-induced myocardial injury through inhibition of inflammatory response and lipid peroxidation response, whereas ulinastatin 80 000 U/kg accentuates myocardial damage.

Objective To assess whether propofol call induce stable psychic dependence in the rats by self-administration experiment. Methods Twenty-four male SD rats 14 weeks old weighing 240一270 mg were studied. Anesthesia was performed with intraperitoneal injection of 3%sodium pentoharbitsl 40 ms/kg and atropine 03 mg/kg.A catheter wag inserted into the right external jugular vein. Penicillin(100 000 U)0.2 ml wag injected through the external jugular vein for anti-infection and heparin sodium(50U/ml)0.1 ml for anticoagulation. The self-administration experiment of 14 days was started after the 7 days of recovery. All the rats were randomly divided into 4 groups(n=6 each):contontrol group(C),propofol 0.56 mg/kg/l group(P1),propofol 1.00 mg/kg group(P2)and pmpofol 1.70 ms/kg group(P3).The experimental events were controlled by a computer with 50 times of the maximum injection per day.The times ofactive and inactive nose-poke response and times of drug iniection were recorded per day.Results Compared with group C and P1,the times of active nosepoke response and injections were significantly increased in group P2 and P3(P<0.01).The times of active nosepoke response and injections per day were significantly increased in group P3 than in group P2(P(0.01).There was no significant difference in the times of active nose-poke response and injections between group C and P1.There was no significant difference in inactive nose-poke resporme between the 4 groups.And the total daily doses of propofol injected in the last 3 days were significantly increased in a dose-dependent manner.Conclusion Propefol can induce the development of psychological dependence in rata and it is related to the dosage.

Objective To study the effects of Lipoxins A4(LXA4)on the expressions of aquaporin(AQP)1,3,5 in type Ⅱ pneumonocytes(ATⅡ)of rat treated with lipopolysaccharide(LPS).Method One pathogenfree male Spree Dawley(SD)rat every time.weighing 200～250 g,were used for the study.The typeⅡpenumonocytes of rats were isolated and purified,and the changes of cellular ultrastructure were observed by electron microscope in order to get the purity quotien＞90%.The type Ⅱ pneumonocytes were divided randomly into five groups,namely,vebicukun group(alcohol 0.7μL/mL),control group,LXA4 group(1×10-7mol/mL),endotoxin group(LPS 1μg/mL)and LXA4+LPS group(LXA4 1×10-7mol/mL,LPS 1μg/mL).AQP-1,3,5 mRNA of in the typeⅡpenumonocytes were assayed by using reversal transcription poly chain reaction(RT-PCR),and the expressions of AQP-1,3,5 protein were detected by using.immunohistochemistry(IHC).One each specimen,these tests were repeated for six times.ANOVA was used for statistical analysis.Results RT-PCR and IHC showed that when AT Ⅱ treated with 1 μg/mL LPS for 4 hours,the AQP-1,3,5 mRNA and the expressions of AQP-1,3,5 protein were significantly decreased in LPS group compared with control group(P＜0.01).However,the AQP-1,3,5 mRNA and the expressions of AQP-1,3,5 protein after application of LXA4 significandy increased in LPS+LXA4 group in comparison with LPS group(LPS+LXA4,AQP1:0.647±0.132,AQP3:0.900±0.856,AQP5:0.879±0.058;LPS,AQP1:0.297±0.133,AQP3:0.512±0.113,AQP5:0.647±0.110;P＜0.01).The AQP-1,3,5 mRNA and the expressions of AQP-1,3,5 protein were aignificandy increased in LXA4 group in comparison with control group(LXA4,AQP1:0.539±0.142,AQP3:0.818 4-0.176,AQP5:0.841±0.066;Blank Control,AQP1:0.518±0.139;AQP3:0.138±0.136,AQP5:0.766±0.066;P＜0.01).Conclusions AQP-1,3,5 exist in typeⅡpenumonoeyte of rata,and the LXA4 can up-regulate the mRNA and protein expressions of AQP-1,3,5 in Type Ⅱ penumonocytes of rats treated with LPS.

Objective To investigate the effects of lipoxin A4 on store-operated calcium channel (SOC) and production of reactive oxygen species in macrophages induced by hpopolysaccharide (LPS).Method Macrophages were randomly assigned Io one of the following six groups:control group,LPS group,Thapsigargin group,lipoxin A4+LPS group,lipoxin A4+Thapsigargin group,2-Aminoethoxydiphenylborate+Thapsigargin group.The intracellular[Ca2+]iwas analyzed by eonfoeal laser microscopy.The production of reactive oxygen specips(ROS) was assayed by flow cytometry.Results LPS increased intracellular[Ca2+]i and reactive oxygen species in a dose-dependent manner.Lipoxin A4 suppressed approximately 75% of the Ca2+ ertry signal induced by thapsigargin and suppressed approximately 93% of the Ca2+ entry signal induced by LPS.The increase in intracellular[Ca2+]i was associated with increased ROS production which was abolished in the presence of lipoxin A4.Conclusions These findings indicate that the LPS-indueed intracellular[Ca2*]i increase depends on the Ca2+entry through SOC channel,and lipoxin A4 inhibits Ca2+ influx and ROS production through SOC channel in ratine maerophages induced by LPS.