L-citrulline is a nonprotein amino acid that plays an important role in human health and has great market demand. Although microbial cell factories have been widely used for biosynthesis, there are still challenges such as genetic instability and low efficiency in the biosynthesis of L-citrulline. In this study, an efficient, plasmid-free, non-inducible L-citrulline-producing strain of Escherichia coli BL21(DE3) was engineered by combined strategies. Firstly, a chassis strain capable of synthesizing L-citrulline was constructed by block of L-citrulline degradation and removal of feedback inhibition, with the L-citrulline titer of 0.43 g/L. Secondly, a push-pull-restrain strategy was employed to enhance the L-citrulline biosynthesis, which realized the L-citrulline titer of 6.0 g/L. Thirdly, the NADPH synthesis and L-citrulline transport were strengthened to promote the synthesis efficiency, which achieved the L-citrulline titer of 11.6 g/L. Finally, fed-batch fermentation was performed with the engineered strain in a 3 L fermenter, in which the L-citrulline titer reached 44.9 g/L. This study lays the foundation for the industrial production of L-citrulline and provides insights for the modification of other amino acid metabolic networks.
Citrulline/biosynthesis* ; Escherichia coli/genetics* ; Metabolic Engineering/methods* ; Fermentation ; NADP/biosynthesis*

Objective:To establish a foundation for the psychological selection of air combat personnel by studying the cognitive ability measurement methods for air combat personnel.Methods:The tests were done for 390 subjects including 142 radar operators, 117 radar academy students, 45 air combat personnel, and 86 radar trainees. Based on job analysis, 5 cognitive test tasks were developed, including graphic discrimination, working memory test, target tracking, voice anti-jamming, and comprehensive management. The discrimination was evaluated by the distribution graphs and coefficients of variation of the test results. The criterion-related validity was examined by correlating the cognitive test scores with the participants' work performance or academic grades, which served as the criteria. Content validity was determined by a 9-level scoring (1-9) of task necessity that collected from 30 air combat personnel and by the assessments of necessity of tested abilities that came from 30 experts. The parallel forms reliability, test-retest reliability and split-half reliability were tested respectively according to the results of each test.Results:The original scores of each test showed approximate normal distribution. The selected indicators' coefficients of variation were 14.4%-111.0%, reliabilities were 0.764-0.827, and criterion-related validities were 0.186-0.445, all of which were statistically significant (all P<0.05). In 30 air combat personnel, 53.3%-83.3% scored 7-9 to the necessity of test items, and 93.3% of 30 experts gave the required or basically required evaluations to the test items. Conclusions:The series tests show good content validity, and discrimination, reliability and the criterion-related validity meet the requirements of psychometrics. Especially the tests of graphic discrimination, working memory and target tracking expressed higher degree of discrimination, and can be used as cognitive ability assessment tool for the selection of air combat personnel.

Objective:To establish a foundation for the psychological selection of air combat personnel by studying the cognitive ability measurement methods for air combat personnel.Methods:The tests were done for 390 subjects including 142 radar operators, 117 radar academy students, 45 air combat personnel, and 86 radar trainees. Based on job analysis, 5 cognitive test tasks were developed, including graphic discrimination, working memory test, target tracking, voice anti-jamming, and comprehensive management. The discrimination was evaluated by the distribution graphs and coefficients of variation of the test results. The criterion-related validity was examined by correlating the cognitive test scores with the participants' work performance or academic grades, which served as the criteria. Content validity was determined by a 9-level scoring (1-9) of task necessity that collected from 30 air combat personnel and by the assessments of necessity of tested abilities that came from 30 experts. The parallel forms reliability, test-retest reliability and split-half reliability were tested respectively according to the results of each test.Results:The original scores of each test showed approximate normal distribution. The selected indicators' coefficients of variation were 14.4%-111.0%, reliabilities were 0.764-0.827, and criterion-related validities were 0.186-0.445, all of which were statistically significant (all P<0.05). In 30 air combat personnel, 53.3%-83.3% scored 7-9 to the necessity of test items, and 93.3% of 30 experts gave the required or basically required evaluations to the test items. Conclusions:The series tests show good content validity, and discrimination, reliability and the criterion-related validity meet the requirements of psychometrics. Especially the tests of graphic discrimination, working memory and target tracking expressed higher degree of discrimination, and can be used as cognitive ability assessment tool for the selection of air combat personnel.

Genome-scale metabolic network model (GSMM) is an extremely important guiding tool in the targeted modification of industrial microbial strains, which helps researchers to quickly obtain industrial microbes with specific traits and has attracted increasing attention. Here we reviewe the development history of GSMM and summarized the construction method of GSMM. Furthermore, the development and application of GSMM in industrial microorganisms are elaborated by using four typical industrial microorganisms (Bacillus subtilis, Escherichia coli, Corynebacterium glutamicum, and Saccharomyces cerevisiae) as examples. In addition, prospects in the development trend of GSMM are proposed.
Corynebacterium glutamicum/genetics* ; Escherichia coli/genetics* ; Metabolic Engineering ; Metabolic Networks and Pathways/genetics*

As a typical food safety industrial model strain, Bacillus subtilis has been widely used in the field of metabolic engineering due to its non-pathogenicity, strong ability of extracellular protein secretion and no obvious codon preference. In recent years, with the rapid development of molecular biology and genetic engineering technology, a variety of research strategies and tools have been used to construct B. subtilis chassis cells for efficient synthesis of biological products. This review introduces the research progress of B. subtilis from the aspects of promoter engineering, gene editing, genetic circuit, cofactor engineering and pathway enzyme assembly. Then, we also summarized the application of B. subtilis in the production of biological products. Finally, the future research directions of B. subtilis are prospected.
Bacillus subtilis/genetics* ; Bacterial Proteins/genetics* ; Gene Editing ; Metabolic Engineering ; Promoter Regions, Genetic

Objective To study the pharmacokinetics of raltitrexed using different ways of drug delivery, including femoral venous infusion, hepatic artery perfusion, hepatic artery injection of lipiodol suspension, hepatic artery perfusion followed by embolization with Gelfoam. Methods According to the administration way of raltitrexed, a total of 40 New Zealand rabbit models with VX2 liver tumor were randomly divided into group A (femoral venous perfusion), group B (hepatic arterial perfusion), group C (hepatic artery injection of lipiodol suspension), and group D(hepatic artery perfusion followed by embolization with Gelfoam). Drug concentration in plasma were determined by using LC-MS/MS method and the pharmacokinetic parameters were calculated. Results After administration of raltitrexed, the Tmax was 5 minutes in all 4 groups. In group A, B, C and D, the values were (5.88±1.39), (7.31±2.60), (9.86±5.10) and (7.19±2.27) respectively, with group C having the longest t1/2 value, which was significantly different with that of group A (P＜0.05); the (ng·ml-1·h-1) values were (2 056.40± 139.17), (1 389.21±180.28), (911.84±105.62) and (1 133.41±181.42)respectively, with the value of group A being obviously higher than that of group B, C and D (P＜0.05) and the value of group C being the lowest; the AUC0-t(ng· ml-1·h-1) values were (5 482.72±1 007.07), (4 156.99±1 475.77), (2 785.13±1 107.36) and (3 903.64±947.25) respectively, with the value of group A being remarkably higher than that of group B, C and D (P＜0.05) and the value of group C being the lowest. Conclusion Compared with the femoral vein infusion way, the ways of hepatic artery infusion, hepatic artery lipiodol suspension injection and hepatic artery perfusion followed by embolization with Gelfoam may promote more raltitrexed to deposit in the tumor area, thus, the curative effect is enhanced, the drug concentration in plasma is lowered and the side effects are alleviated.

Obgective To investigate the impact of different ways and doses of recombinant human interferon o1b(rhIFN-α1b) on antiviral effect on respiratory syncytial virus(RSV)-effected mice and signal pathway of JAK/ STAT.Methods Forty-eight mice were divided randomly into 6 groups,negative control group,RSV-infection model group,12.5,25.0,50.0 μg rhIFN-α1 b atomization inhalation of intervention group,and 12.5 μg rhIFN-α 1 b injection of intervention group.After continuous drug therapy for 5 days,the left lung tissues of mice were aseptically dissected in the sixth day.Then it were observed lung tissue pathology changes by optical microscope,and expression of STAT1 and STAT2 protein with laser scanning confocal microscopy.Results It was observed that RSV-infection model mice's lungs had significant inflammatory injury under light microscope.After treatments of rhIFN-α 1b,it showed that the mice lung tissue had recovery of inflammation on different degrees.The group of inhaled rhIFN-o1b 50.0 μg was damaged on lightest degree.There were statistically significant differences between each group (all P ＜ 0.05).The expression of STAT1 and STAT2 protein in RSV-infection model mice's lungs decreased remarkably under fluorescene microscopy.Treatments of rhIFN-α 1b increased the expression of STAT1 and STAT2 inhibited by RSV-infection.The expression of STAT1 and STAT2 protein of the inhaled rhIFN-α1b 50.0 μg group increased significantly.The differences between groups were statistically significant(all P ＜ 0.05).Conclusions rhIFN-α 1 b played an important role in anti-RSV effects,simultaneously,it could improve the activity of JAK/STAT signal pathway inhibited by RSV-infection.The treatment effect of rhIFN-α 1b deliveried by atomization inhalation was better than that of intraperitoneal injection.And curative effect is proportional to the atomization inhalation dose within a certain range.

Objective This study aims to investigate the clinical value of percutaneous vertebroplasty (PVP)combined with strontium-89 (89 Sr)on patients with spinal malignant tumor.Methods Seventy four patients who were diagnosed as spinal malig-nant tumor were divided into two groups randomly.37 patients of the control group were treated by PVP only,and 37 patients of joint group were treated by PVP and 89 Sr together.Then the clinical effect of the joint group and control group was compared after treatment.Results After treatment,the quality of life,ratio of pain relief,clinical effect and survival time in joint group were dis-tinctly better than control group (P <0.05).Conclusion PVP combined with 89 Sr can be an effective and safe treatment for pa-tients with spinal malignant tumor.

Objective To explore the diagnostic value of three-dimensional ultrasound parameters-vascularity index (VI) and the volume of kidney in chronic kidney disease (CKD). Methods A total of 80 CKD patients at different stages and 30 healthy adults were enrolled in the study. VI and the renal volume were calculated with three-dimensional ultrasound, while resistance index (RI), cortical thickness (CT) and the volume of kidney were calculated with two-dimensional ultrasound, and the correlation of those parameters were analyzed statistically. Results VI of CKD2 patients reduced significantly compared with the control group, and RI of CKD3 patients increased significantly, CT of CKD3 patients reduced significantly. The diagnostic sensitivity, specificity and diagnostic value of VI in patients with early and late CKD were all higher than thpse of RI. Compared with the control group, three-dimensional ultrasound of renal volume and two-dimensional ultrasound volume of CKD 1 patients increased significantly, three-dimensional ultrasound volume of CKD2 patients reduced significantly, and two-dimensional ultrasound volume of CKD4 patients reduced significantly. There was significant negative correlation among VI, three-dimensional ultrasound volume, CT, two-dimensional ultrasound volume and pathological change scoring (r=-0.67, -0.52, -0.43, -0.52). Conclusion VI and three-dimensional ultrasound volume can detect renal function damage more earlier and sensitively than RI and two-dimensional ultrasound volume.

To obtain the P8 protein of Rice gall dwarf virus (RGDV) with biological activity, its outer coat protein gene S8 was expressed in Spodoptera frugiperda (Sf9) insect cells using the baculovirus expression system. The S8 gene was subcloned into the pFastBacTM1 vector, to produce the recombinant baculovirus transfer vector pFB-S8. After transformation, pFB-S8 was introduced into the competent cells (E. coli DH10Bac) containing a shuttle vector, Bacmid, generating the recombinant bacmid rbpFB-S8. After being infected by recombinant baculovirus rvpFB-S8 at different multiplicities of infection, Sf9 cells were collected at different times and analyzed by SDS-PAGE, Western blotting and immunofluorescence microscopy. The expression level of the P8 protein was highest between 48-72 h after transfection of Sf9 cells. Immunofluorescence microscopy showed that P8 protein of RGDV formed punctate structures in the cytoplasm of Sf9 cells.