Group A Streptococcus (GAS) is a very important pathogen, especially for children.On a global scale, GAS is an important cause of morbidity and mortality.But the burden of disease caused by GAS is still unknown in China and also has not obtained enough attention.For this purpose, the expert consensus is comprehensively described in diagnosis, treatment and prevention of GAS diseases in children, covering related aspects of pneumology, infectiology, immunology, microbiology, cardiology, nephrology, critical care medicine and preventive medicine.Accordingly, the consensus document was intended to improve management strategies of GAS disease in Chinese children.

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

Novel Coronavirus Pneumonia (NCP) is a class B infectious disease, which is prevented and controlled according to class A infectious diseases. Recently, children′s NCP cases have gradually increased, and children′s fever outpatient department has become the first strategic pass to stop the epidemic. Strengthening the management of the fever diagnosis process is very important for early detection of suspected children, early isolation, early treatment and prevention of cross-infection. This article proposes prevention and control strategies for fever diagnosis, optimizes processes, prevents cross-infection, health protection and disinfection of medical staff, based on the relevant diagnosis, treatment, prevention and control programs of the National Health and Health Commission and on the diagnosis and treatment experience of experts in various provinces and cities. The present guidance summarizes current strategies on pre-diagnosis; triage, diagnosis, treatment, and prevention of 2019-nCoV infection in common fever, suspected and confirmed children, which provide practical suggestions on strengthening the management processes of children′s fever in outpatient department during the novel coronavirus pneumonia epidemic period.

Objective:To summarized the experience of 149 cases of critical pediatric cardiac surgery in a single-center during the epidemic period, for providing a safe and feasible management strategy.Methods:Based on the epidemiological characteristics of COVID-19, a strategy consisting of 14 days of isolation was established for the arrangement of cardiac surgery in children during the epidemic period. Retrospective analysis of clinical data of 149 cases of critical cardiac surgery performed from January 23, 2020 to March 20, 2020 under the guidance of this strategy. The primary composite endpoint was death and suspected or confirmed COVID-19.Results:The median age of the children undergoing surgery was 136 days; 73(49.0%) cases were male. Twenty-one cases (14.1%) came from Shanghai, one case (0.7%) came from Hubei Province, and 127 cases (85.2%) came from areas other than Hubei and Shanghai. One patient (0.7%) outside Shanghai who had been isolated for less than 14 days carried emergency surgery under special protection; other 148 patients (99.3%) underwent elective early repair procedure. One patient (0.7%) died, and no COVID-19 was confirmed or suspected.Conclusion:During the COVID-19 epidemic, pediatric cardiac surgery can be safely performed using a specific management strategy, which can be used as a reference when major public health events occur.

Objective: To evaluate the induced membrane technique combined with microsurgery for repair of open leg fractures of Gustilo types ⅢB-C. Methods: This retrospective study reviewed 15 patients who had been treated for open leg fractures of Gustilo types ⅢB and ⅢC by the induced membrane technique and microsurgery between January 2015 and January 2017 at Institute of Orthopedics, 920 Hospital, The Joint Logistic Service of The People’s Liberation Army. They were 10 men and 5 women, aged from 18 to 41 years(average 32 years). There were 9 cases of Gustilo type IIIB and 6 ones of Gustilo type IIIC. After thorough debridement, the fractures were reduced and fixated temporarily using external frames. The bone defects were filled with antibiotic bone cement to induce biofilm formation. After necessary reconstruction of limb structures, including neurovascular repair and transposition of tendon and nerve, crucial soft-tissue wounds were covered with surgical flaps. In the secondary surgery 6 to 8 weeks later, with the external frames replaced by internal fixation or not, the bone cement was removed without damaging the biofilm before graft reconstruction with autogenous cancellous bone. Results: The 15 legs were all salvaged successfully. The in-hospital time ranged from 21 to 39 days (mean, 29 days). Crucial wounds were repaired primarily without any severe or persistent infection. Follow-ups ranged from 12 to 24 months (average, 15 months). Bone union time ranged from 10 to 17 months (average, 11.2 months) with satisfactory aesthetic and functional recovery of the leg. Conclusion Reconstruction of open leg fractures of Gustilo types Ⅲ B-C with induced membrane technique and microsurgery can result in decreased therapeutic duration, reduced complications and positive outcomes.

Industrial fermentation focuses on realizing the uniform of high titer, high yield, and high productivity. Multi-scale analysis and regulation, including molecule level, cell level, and bioreactor level, facilitate global optimization and dynamic balance of fermentation process, which determine high efficiency of biosynthesis, targeted directionality of bioconversion, process robustness, and well-organized system. In this review, we summariz and discuss advances in multi-scale analysis and regulation for fermentation process focusing on the following four aspects: 1) kinetic modeling of metabolic pathways, 2) characteristic of cell metabolism, 3) co-coupling fermentation and purification, and 4) bioreactor design. Integrating multi-scale analysis of fermentation process and integrating multi-scale regulation are expected as an important strategy for realizing highly efficient fermentation by industrial microorganisms.
Bioreactors ; Fermentation ; Industrial Microbiology ; Kinetics ; Metabolic Networks and Pathways

Chitinase has a wide industrial application prospect. For example, it can degrade shrimp shells, crab shells and other crustacean waste into high value-added chitooligosaccharides. However, the low catalytic efficiency of chitinase greatly limits the production of chitooligosaccharides. In previous study, the we expressed a chitinase Chisb with high catalytic efficiency and studied its enzymatic properties. In order to further improve the catalytic efficiency of Chisb, with R13NprB-C-SP-H as the parent, here error-prone PCR was used to construct random mutant library to conduct directed evolution of chitinase Chisb. Two mutants C43D and E336R were obtained with 96-well plate primary screening and shaker-screening, and their enzymatic properties were also studied. The optimum temperature of C43D and E336R was 55 °C, and the optimum pH of C43D was 5.0, while that of E336R was 9.0. The catalytic efficiency of C43D and E336R was 1.35 times and 1.57 times higher than that of control. The chitooligosaccharide concentration of E336R and C43D was 2.53 g/L and 2.06 g/L, improved by 2.84 times and 2.31 times compared with the control (0.89 g/L), respectively. In addition, the substrate conversion rate of mutants E336R and C43D was 84.3% and 68.7%, improved by 54.6% and 39% compared with the control (29.7%), respectively. In summary, the study indicates that random mutation introduced by error-prone PCR can effectively improve the catalytic efficiency of chitinase Chisb. The positive mutants with higher catalytic efficiency obtained in the above study and their enzymatic property analysis have important research significance and application value for the biosynthesis of chitooligosaccharides.
Biocatalysis ; Chitin ; analogs & derivatives ; Chitinases ; Hydrogen-Ion Concentration ; Polymerase Chain Reaction

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.