Studies on lycopene synthesis in Escherichia coli were not only able to gain the strains with high yield and less by-products, but also able to test functions of genes or gene clusters. In this article, the cDNA sequences of tomato LeGGPS2 and LePSY1 as well as the coding sequence of crtI from Erwinia uredovora, each of which was added a ribosome biding site, were controlled by T7 promoter and terminator alone or combined, and expressed in E. coli BL21 (DE3) to induce lycopene synthesis. The results show that only T7::crtI-LeGGPS2-LePSY1 expressed tri-cistronically could produce lycopene, and 2.124 mg/g dry cell weight oflycopene was obtained when fermented for 5 h at 30 degrees C after mixing 80 micromol/L IPTG at the later logarithmic phase while the seed broth of 1:50 (V/V) was inoculated into LB medium (pH 6.8) containing 3% sucrose and cultured for 8 h at 37 degrees C. The results confirmed the function of the prokaryonized LeGGPS2 and LePSY1 and their synergy with crtI, and also laid a foundation to establish an independent lycopene synthetic pathway in the tomato plastid.
Bacterial Proteins ; genetics ; Carotenoids ; biosynthesis ; genetics ; Cloning, Molecular ; Erwinia ; genetics ; Escherichia coli ; genetics ; metabolism ; Genetic Engineering ; Plant Proteins ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics

Cell-based therapies have been used as promising treatments for several untreatable diseases. However, cellbased therapies have side effects such as tumorigenesis and immune responses. To overcome these side effects, therapeutic effects of exosomes have been researched as replacements for cell-based therapies. In addition, exosomes reduced the risk that can be induced by cell-based therapies. Exosomes contain biomolecules such as proteins, lipids, and nucleic acids that play an essential role in cell–cell and cell–matrix interactions during biological processes. Since the introduction of exosomes, those have been proven perpetually as one of the most effective and therapeutic methods for incurable diseases. Much research has been conducted to enhance the properties of exosomes, including immune regulation, tissue repair, and regeneration. However, yield rate of exosomes is the critical obstacle that should be overcome for practical cell-free therapy. Three-dimensional (3D) culture methods are introduced as a breakthrough to get higher production yields of exosomes. For example, hanging drop and microwell were well known 3D culture methods and easy to use without invasiveness. However, these methods have limitation in mass production of exosomes. Therefore, a scaffold, spinner flask, and fiber bioreactor were introduced for mass production of exosomes isolated from various cell types. Furthermore, exosomes treatments derived from 3D cultured cells showed enhanced cell proliferation, angiogenesis, and immunosuppressive properties. This review provides therapeutic applications of exosomes using 3D culture methods.

Objective:To study the characteristics and management of peripancreatic effusion in chronic pancreatitis.Methods:Data of 32 patients with chronic pancreatitis and 141 acute pancreatitis admitted to the First Affiliated Hospital of Guangxi Medical University from January 2018 to December 2019 were collected. According to the Atlanta classification, the peripancreatic effusion was divided into four categories: acute peripancreatic fluid collection (APFC), acute necrotic collection(ANC), pancreatic pseudocyst (PPC) and walled-off necrosis (WON). The general information, clinical manifestations, medical history, laboratory examination indicators and treatment of the four types of patients were recorded and analyzed.Results:Among the 32 patients with chronic pancreatitis complicated with peripancreatic effusion, 27 patients (84.4%) were diagnosed as having PPC, 3 patients (9.4%) WON and 2 (6.2%) APFC. No chronic pancreatitis with ANC was found. The incidence of PPC was higher in patients with chronic pancreatitis than those with acute pancreatitis [84.4% (27/32) VS 31.2% (44/141), P<0.01], and the APFC was lower [6.2% (2/32) VS 24.8% (35/141), P=0.021]. The incidence of ANC was also lower [0.0% (0/32) VS 36.9% (52/141), P<0.01], and there was no significant difference in the incidence of WON [9.4% (3/32) VS 7.1% (10/141), P=0.944]. Compared with patients with peripancreatic effusion of chronic pancreatitis, acute pancreatitis showed a higher proportion of clinical manifestations: fever [19.1% (27/141) VS 3.1% (1/32)], nausea [59.6% (84/141) VS 21.9% (7/32)], vomit [56.7% (80/141) VS 21.9% (7/32)], tenderness [79.4% (112/141) VS 34.4% (11/32)], rebounding pain [42.6% (60/141) VS 0.0% (0/32)], increase of C reactive protein [95.7% (135/141) VS 40.6% (13/32)] ( P< 0.05), and the mean hospital stay was longer (13 days VS 11 days, P=0.048). Imaging examination showed that the proportion of lesions >5 cm in diameter in PPC patients with acute pancreatitis was higher than those with chronic pancreatitis [70.5% (31/44) VS 29.6% (8/27), P=0.001]. WON in chronic pancreatitis patients was limited to the pancreas [3/3 VS 1/10, P =0.014]. In terms of treatment strategies, 25 patients (78.1%) received conservative treatment in 32 chronic pancreatitis. There was no significant difference in treatment strategy between patients with acute pancreatitis and those with chronic pancreatitis. Conclusion:In the peripancreatic effusion of chronic pancreatitis, PPC is the most common. Peripancreatic effusion is mainly treated conservatively. There is no difference in treatment among different types of peripancreatic effusion in chronic pancreatitis. However, compared with chronic pancreatitis, peripancreatic effusion in acute pancreatitis may need more active intervention.

Objective:To develop a robotic digestive endoscope system (RDES) and to evaluate its feasibility, safety and control performance by experiments.Methods:The RDES was designed based on the master-slave control system, which consisted of 3 parts: the integrated endoscope, including a knob and button robotic control system integrated with a gastroscope; the robotic mechanical arm system, including the base and arm, as well as the endoscopic advance-retreat control device (force-feedback function was designed) and the endoscopic axial rotation control device; the control console, including a master manipulator and an image monitor. The operator sit far away from the endoscope and controlled the master manipulator to bend the end of the endoscope and to control advance, retract and rotation of the endoscope. The air supply, water supply, suction, figure fixing and motion scaling switching was realized by pressing buttons on the master manipulator. In the endoscopy experiments performed on live pigs, 5 physicians each were in the beginner and advanced groups. Each operator operated RDES and traditional endoscope (2 weeks interval) to perform porcine gastroscopy 6 times, comparing the examination time. In the experiment of endoscopic circle drawing on the inner wall of the simulated stomach model, each operator in the two groups operated RDES 1∶1 motion scaling, 5∶1 motion scaling and ordinary endoscope to complete endoscopic circle drawing 6 times, comparing the completion time, accuracy (i.e. trajectory deviation) and workload.Results:RDES was operated normally with good force feedback function. All porcine in vivo gastroscopies were successful, without mucosal injury, bleeding or perforation. In beginner and advanced groups, the examination time of both RDES and ordinary endoscopy tended to decrease as the number of operations increased, but the decrease in time was greater for operating RDES than for operating ordinary endoscope (beginner group P=0.033; advanced group P=0.023). In the beginner group, the operators operating RDES with 1∶1 motion scaling or 5∶1 motion scaling to complete endoscopic circle drawing had shorter completion time [1.68 (1.40, 2.17) min, 1.73 (1.47, 2.37) min VS 4.13 (2.27, 5.16) min, H=32.506, P<0.001], better trajectory deviation (0.50±0.11 mm, 0.46±0.11 mm VS 0.82±0.26 mm, F=38.999, P<0.001], and less workload [42.00 (30.00, 50.33) points, 43.33 (35.33, 54.00) points VS 52.67 (48.67, 63.33) points, H=20.056, P<0.001] than operating ordinary endoscope. In the advanced group, the operators operating RDES with 1∶1 or 5∶1 motion scaling to complete endoscopic circle drawing had longer completion time than operating ordinary endoscope [1.72 (1.37, 2.53) min, 1.57 (1.25, 2.58) min VS 1.15 (0.86, 1.58) min, H=13.233, P=0.001], but trajectory deviation [0.47 (0.13, 0.57) mm, 0.44 (0.39, 0.58) mm VS 0.52 (0.42, 0.59) mm, H=3.202, P=0.202] and workload (44.62±21.77 points, 41.24±12.57 points VS 44.71±17.92 points, F=0.369, P=0.693) were not different from those of the ordinary endoscope. Conclusion:The RDES enables remote control, greatly reducing the endoscopists' workload. Additionally, it gives full play to the cooperative motion function of the large and small endoscopic knobs, making the control more flexible. Finally, it increases motion scaling switching function to make the control of endoscope more flexible and more accurate. It is also easy for beginners to learn and master, and can shorten the training period. So it can provide the possibility of remote endoscopic control and fully automated robotic endoscope.