O-acetyl-L-homoserine (OAH) is a promising platform compound for the production of L-methionine and other valuable compounds, while its low yield and low conversion rate limit the industrial application. To solve these problems, we constructed a strain for high OAH production with the previously constructed L-homoserine producer Escherichia coli HS33 as the chassis by systematic metabolic engineering. Firstly, PEP accumulation, pyruvate utilization, and OAH synthesis pathway (overexpressing aspB, aspA, and thrA^C1034T) were enhanced to obtain an initial strain accumulating 13.37 g/L OAH. Subsequently, the co-factor synthesis genes were integrated to supply reducing power and energy, which increased the yield to 15.79 g/L. The OAH yield of the engineered strain OAH28 was further increased to 17.49 g/L by strengthening the acetic acid reuse pathway, improving the supply of acetyl-CoA, and regulating the expression of MetX from different sources. Finally, in a 5 L fermenter, OAH28 achieved an OAH titer of 47.12 g/L, with a glucose conversion rate of 32% and productivity of 0.59 g/(L·h). The results lay a foundation for increasing the OAH production by metabolic engineering and give insights into the industrial production of OAH.
Metabolic Engineering/methods* ; Escherichia coli/genetics* ; Homoserine/biosynthesis* ; Fermentation

Synthetic biology is a crucial tool for the development of the bio-industry and bio-economy, representing a significant aspect of new quality productive forces. As a core course for graduate students in bioengineering, Synthetic Biology plays a vital role in ensuring the supply of essential talents for the development of the bio-industry in the new era. To better serve regional economic development and provide high-level talents for China's progress in the bio-industry, we analyzed typical issues encountered in the past teaching activities, set up a multi-disciplinary teaching team, optimized the course contents, adjusted the teaching mode, and mobilized students' learning interest. With the application of scientific research project as the starting point, we guided students to think and discuss deeply through the simulation of application writing and project defense, which improved students' critical thinking and innovative thinking. With industrialization as a focus, we explored a new training model combining production, education, and research through the joint practice base of the university and enterprises introduced typical cases of biomanufacturing to encourage students to engage in scientific research. The teaching reform significantly enhances the comprehensive abilities and national sentiments of graduate students. This paper hopes to serve as a reference for colleagues engaged in teaching in this field.
Synthetic Biology/education* ; Teaching ; China ; Humans

Abstract In recent years, the prevalence of overweight and obesity among children and adolescents has risen rapidly, posing a serious threat to their physical and mental health. To provide scientific, systematic, and standardized weight management guidance for overweight and obese children and adolescents, the study focuses on the core concept of healthy lifestyle intervention, integrates multidisciplinary expert opinions and research findings,and proposes a comprehensive multidisciplinary intervention framework covering scientific exercise intervention, precise nutrition and diet, optimized sleep management, and standardized psychological support. It calls for the establishment of a multi agent collaborative management mechanism led by the government, implemented by families, fostered by schools, initiated by individuals, optimized by communities, reinforced by healthcare, and coordinated by multiple stakeholders. Emphasizing a child and adolescent centered approach, the consensus advocates for comprehensive, multi level, and personalized guidance strategies to promote the internalization and maintenance of a healthy lifestyle. It serves as a reference and provides recommendations for the effective prevention and control of overweight and obesity, and enhancing the health level of children and adolescents.

Objective:To evaluate the clinical value of a capillary electrophoresis-based method for gene diagnosis of hyperphenylalaninemia.Methods:In this single-center prospective study, 40 newborns with suspected hyperphenylalaninemia detected by neonatal liquid chromatography-tandem mass spectrometry screening at Nanjing Maternity and Child Health Care Hospital from February 2021 to February 2023 were included, with 22 males, 18 females and a mean age at diagnosis of 21.93 days.Capillary electrophoresis was used to detect 85 variants of the phenylalanine hydroxylase ( PAH) gene in 40 newborns with suspected hyperphenylalaninemia.The PAH gene of undiagnosed patients was further analyzed by Sanger sequencing.The detection rate, sensitivity and specificity of capillary electrophoresis were calculated. Results:Among these 40 newborns with suspected hyperphenylalaninemia, 71 PAH variants were detected by capillary electrophoresis, 32 patients were clearly diagnosed, only 1 pathogenic variant was found in 5 patients, and no pathogenic variant was found in the last 3 patients.Therefore, the detection rate, sensitivity and specificity of capillary electrophoresis for analysis of the PAH gene were 80.00%, 88.75% and 100%, respectively. Conclusions:The capillary electrophoresis-based method can rapidly, efficiently and accurately detect PAH gene variants at lower cost and is a promising gene detection method for hyperphenylalaninemia in clinical practice.

Major natural disasters seriously threaten human life and health. After earthquakes and other catastrophes, survivors are often trapped in the confined spaces caused by the collapse of ground and buildings, with relative separation from the outside world, restricted access, complex environment, and oncoming or ongoing unsafety, leading to the rescue extremely difficult. In order to save lives and improve the outcome more efficiently in the confined spaces after natural disasters, it is very important to standardize and reasonably apply the trauma assessment and first aid workflow. This study focuses on trauma assessment and first aid. From the aspects of trauma assessment, vital signs stabilization, hemostasis and bandaging, post-trauma anti-infection, and the transportation of patients, a trauma first aid work process suitable for a small space of a major natural disaster is formed, It is helpful to realize the immediate and efficient treatment of trauma in the confined spaces after natural catastrophes, to reduce the rate of death and disability and improve the outcome of patients.
Humans ; Disasters ; First Aid ; Confined Spaces ; Earthquakes

Objective:To investigate the effects of sodium-glucose cotransporter 2 inhibitor dapagliflozin on myocardial remodeling in mice with diabetic cardiomyopathy and related mechanisms.Methods:Between January and December 2021, 60 6-week-old male C57BL/6J mice were chosen for the study, 40 were used to establish a diabetic cardiomyopathy model and the model was established in 28 mice, of whom, 14 were assigned to a non-intervention group and 14 to a dapagliflozin treatment group(intervention group).The rest of the 20 mice were in the control group.The mice in the intervention group were treated with dapagliflozin via oral gavage for 12 weeks.Cardiac structure and function were measured by ultrasound, the degree of myocardial fibrosis was evaluated by histology and electron microscopy, the concentrations of inflammatory factors were detected by enzyme-linked immunosorbent assays, apoptosis of myocardial cells was examined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL), and the level of myocardial oxidative stress was evaluated by dihydroethidium fluorescence.Results:At the end of the experiments, the body weight and fasting blood glucose in the intervention group were slightly lower than in the non-intervention group, but the difference was not statistically significant, while values from cardiac function parameters such as left ventricular ejection fraction were more favorable than in the non-intervention group[(61.07±4.66)% vs.(45.8±4.80)%, t=-5.24, P<0.05].Compared with the non-intervention group, the intervention group had alleviated myocardial hypertrophy, less myocardial disarray, and reduced collagen volume fraction[(18.4±1.9)% vs.(31.8±3.7)%, t=-12.0, P<0.05].Furthermore, the concentrations of inflammatory factors in the intervention group were lower than in the control group[interleukin-6: (82.19±10.90)ng/L vs.(291.02±31.02)ng/L, t=23.8, P<0.05; tumor necrosis factor-α: (70.45±12.13)ng/L vs.(201.31±27.10)ng/L( t=16.5), P<0.05; perforin 3: (13.05±2.04)μg/L vs.(42.40±1.26)μg/L( t=45.8), P<0.05; the index of myocardial apoptosis: 1.736±0.247 vs.0.864±0.129, t=11.7, P<0.05].The level of myocardial oxidative stress in the non-intervention group was higher than in the intervention group(2.655±0.252 vs.1.274±0.298, t=-13.3, P<0.05). Conclusions:Dapagliflozin can reduce myocardial hypertrophy and inhibit myocardial fibrosis through mitigating myocardial oxidative stress and inflammatory response, thus suppressing myocardial remodeling and ultimately protecting cardiac function in diabetic cardiomyopathy mice.

L-methionine, also known as L-aminomethane, is one of the eight essential amino acids required by the human body and has important applications in the fields of feed, medicine, and food. In this study, an L-methionine high-yielding strain was constructed using a modular metabolic engineering strategy based on the M2 strain (Escherichia coli W3110 ΔIJAHFEBC/PAM) previously constructed in our laboratory. Firstly, the production of one-carbon module methyl donors was enhanced by overexpression of methylenetetrahydrofolate reductase (methylenetetrahydrofolate reductase, MetF) and screening of hydroxymethyltransferase (GlyA) from different sources, optimizing the one-carbon module. Subsequently, cysteamine lyase (hydroxymethyltransferase, MalY) and cysteine internal transporter gene (fliY) were overexpressed to improve the supply of L-homocysteine and L-cysteine, two precursors of the one-carbon module. The production of L-methionine in shake flask fermentation was increased from 2.8 g/L to 4.05 g/L, and up to 18.26 g/L in a 5 L fermenter. The results indicate that the one carbon module has a significant impact on the biosynthesis of L-methionine, and efficient biosynthesis of L-methionine can be achieved through optimizing the one carbon module. This study may facilitate further improvement of microbial fermentation production of L-methionine.
Humans ; Methionine ; Methylenetetrahydrofolate Reductase (NADPH2) ; Carbon ; Cysteine ; Escherichia coli/genetics* ; Hydroxymethyl and Formyl Transferases ; Carrier Proteins ; Escherichia coli Proteins

Objective: To evaluate the accuracy and feasibility of coronary artery calcium score ( CACS) on virtual non-contrast scan ( VNC) images obtained from coronary artery CT angiography ( CCTA) scan with dual －layer spectral detector CT (SDCT) ． Methods : The data of 197 patients who underwent CCTA scan in hospital were analyzed retrospectively，and 88 patients with CACS ＞0 were further analyzed． Linear regression analysis of CACS and coronary artery calcium volume ( CACV) of true non-contrast (TNC) images and VNC images ( CACS-TNC， CACS-VNC，CACV-TNC，CACV-VNC) was performed to obtain linear regression equation and correction coefficients λ 1AVG and λ2AVG ．CACS-VNC and CACV-VNC were corrected by the corresponding regression equation and recorded as CCACS-VNC and CCACV-VNC，respectively．Spearman correlation coefficient was used for correlation analysis and Bland-Altman plot was used for consistency test．Mann-Whitney U test was used to compare the difference between the two groups. Results : For the total coronary artery，there was a strong correlation between CACS- TNC and CACS-VNC (rs = 0. 952，P ＜0. 001 ，λ 1AVG = 2. 19 ) ，CACV-TNC and CACV-VNC ( rs = 0. 954，P < 0. 001，λ2AVG = 1. 93) ．The results of Mann-Whitney U test showed that there was no significant difference between CACS-TNC and CCACS-VNC or between CACV-TNC and CCACV-VNC，and the Bland-Altman plot showed good consistency between CACS-TNC and CCACS-VNC ，CACV-TNC and CCACV-VNC． Conclusion VNC images based on SDCT can accurately measure CACS and be used for cardiovascular risk classification，which is expected to replace TNC scan and reduce the radiation dose of patients.

Unnatural amino acids are widely used in medicine, pesticide, material, and other industries and the green and efficient synthesis has attracted a lot of attention. In recent years, with the rapid development of synthetic biology, microbial cell factories have become a promising means for biosynthesis of unnatural amino acids. This study reviewed the construction and application of microbial cell factories for unnatural amino acid, including the synthetic pathway reconstruction, design/modification of key enzymes and their coordinated regulation with precursors, blocking of competitive alternative pathways, and construction of cofactor circulation systems. Meanwhile, on the basis of the new principles for designing the microbial cell factories, new biosynthetic pathways adapted to cells and the production environment, as well as new biomanufacturing system established based on cell adaptive evolution and intelligent fermentation regulation, we looked forward to the further construction and application of microbial cell factories for industrial bio-production.
Amino Acids/genetics* ; Biosynthetic Pathways ; Fermentation ; Metabolic Engineering ; Synthetic Biology

Myostatin gene (MSTN) encodes a negative regulator for controlling skeletal muscle growth in animals. In this study, MSTN^-/- homozygous mutants with "double muscle" phenotypic traits and stable inheritance were bred on the basis of MSTN gene editing rabbits, with the aim to establish a method for breeding homozygous progeny from primary MSTN biallelic mutant rabbits. MSTN^-/- primary mutant rabbits were generated by CRISPR/Cas9 gene editing technology. The primary mutant rabbits were mated with wild type rabbits to produce F1 rabbits, whereas the F2 generation homozygous rabbits were bred by half-sibling mating or backcrossing with F1 generation rabbits of the same mutant strain. Sequence analysis of PCR products and its T vector cloning were used to screen homozygous rabbits. The MSTN mutant rabbits with 14-19 week-old were weighed and the difference of gluteus maximus tissue sections and muscle fiber cross-sectional area were calculated and analyzed. Five primary rabbits with MSTN gene mutation were obtained, among which three were used for homozygous breeding. A total of 15 homozygous rabbits (5 types of mutants) were obtained (M2-a: 3; M2-b: 2; M3-a: 2; M7-a: 6; M7-b: 2). The body weight of MSTN^-/- homozygous mutant rabbits aged 14-19 weeks were significantly higher than that of MSTN^+/+ wild-type rabbits of the same age ((2 718±120) g vs. (1 969±53) g, P < 0.01, a 38.0% increase). The mean cross sections of gluteus maximus muscle fiber in homozygous mutant rabbits were not only significantly higher than that of wild type rabbits ((3 512.2±439.2) μm² vs. (1 274.8±327.3) μm², P < 0.01), but also significantly higher than that of MSTN^+/- hemizygous rabbits ((3 512.2±439.2) μm² vs. (2 610.4±604.4) μm², P < 0.05). In summary, five homozygous mutants rabbits of MSTN^-/- gene were successfully bred, which showed a clear lean phenotype. The results showed that the primary breeds were non-chimeric mutant rabbits, and the mutant traits could be inherited from the offspring. MSTN^-/- homozygous mutant rabbits of F2 generation could be obtained from F1 hemizygous rabbits by inbreeding or backcrossing. The progenies of the primary biallelic mutant rabbits were separated into two single-allelic mutants, both of which showed a "double-muscle" phenotype. Thus, this study has made progress in breeding high-quality livestock breeds with gene editing technology.
Animals ; CRISPR-Cas Systems/genetics* ; Gene Editing ; Muscle, Skeletal/metabolism* ; Mutation ; Myostatin/metabolism* ; Phenotype ; Rabbits