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 investigate the organ protective role and the underlying mechanism of nafamostat mesylate(NM)in a renal ischemia-reperfusion injury(RIRI)model.Methods A total of 21 healthy male Sprague-Dawley(SD)rats were randomly assigned to 3 groups(n=7 in each group),including the sham operation group(Sham group),the RIRI group,and the NM intervention group(NM group).The RIRI and NM groups underwent ischemia-reperfusion injury(IRI)modeling.The NM group was given an intraperitoneal injection of NM at 0.75 mg/kg before modeling.Venous blood and renal tissue samples were then collected from the rats 24 hours after modeling.The levels of serum creatinine,cystatin C,and serum inflammatory factors were determined using the serum samples.Hematoxylin-eosin(HE)staining and TUNEL stainings were performed on the renal tissues to evaluate the damage of the renal tissues.The localization and expression of HMGB1 were analyzed by immunofluorescence and Western blotting,respectively.Single-cell RNA sequencing of the nuclei was performed to obtain the single-cell transcriptome of the kidneys from the rats in the RIRI and the NM groups and to acquire the RIRI cell profile.The cells were annotated according to the cell marker genes to explore the cell type composition in the disease model and the functional status of immune cells between the groups.Results 1)Compared with those of the Sham group,the levels of cystatin C,creatinine,and inflammatory factors in the RIRI and NM groups were significantly increased,and the expression levels in the NM group were lower than those in the RIRI group(P＜0.05).Compared with those of the RIRI group,the tubular injury score and apoptosis rate in the NM group were significantly decreased(P＜0.05),but those of both the NM and RIRI groups were higher than those of the sham group.Compared with that in the RIRI group,the expression of HMGB1 in the NM group was significantly decreased(P＜0.05),but the expression levels in both the RIRI and NM groups were higher than that in the sham group.Immunofluorescence showed that there was increased cytoplasmic expression of HMGB1 in both the NM and RIRI groups,with the increase being more prominent in the RIRI group.2)A total of 13 major cell populations were identified through the single-nucleus sequencing results.The proportion of tubular cells in the NM group was higher,with the HMGB1 gene being highly expressed in the damaged proximal convoluted tubular cells.The proportion of the polarized Macro3 cell subpopulation in the macrophages in the NM group was lower compared to that in the RIRI group.Conclusion NM may play a protective role in a rat model of RIRI,and its underlying mechanisms may be related to the regulation of the functional abnormalities of HMGB1-mediated macrophages.

Objective To measure the air-absorbed dose rate of gamma radiation in public areas for the situation of the local radiation environment. Methods Using a large-volume γ spectrometer system with a NaI(Tl) detector mounted on a UAV, we conducted large-scale airborne radiation monitoring in public areas in southwestern China, to measure the air-absorbed dose rate at a height of 1 m from the earth’s surface. Results The airborne radiation monitoring data were used to analyze the local radiation environment. The mean air-absorbed dose rate at a height of 1 m was 43.6 ± 12.9 nGy/h. Seven abnormal radiation points were detected, and two of them were located where construction was ongoing. At one of the abnormal radiation points, FH40G meter measurements showed that the air-absorbed dose rate at a height of 1 m was up to 22.0 μGy/h. Field soil samples were collected for HPGe γ spectrometer analysis: the ²³²Th radionuclide activity concentration was 96.0 kBq/kg, and the ²²⁶Ra radionuclide activity concentration was 9.9 kBq/kg. Conclusion Using the UAV-mounted large-volume γ spectrometer system with NaI(Tl) detectors for large-scale airborne monitoring is a fast and effective method for dragnet monitoring of the level of radiation in public areas.

【Objective】 To explore the the potential risks of antiretroviral therapy(ART) drugs on blood safety among blood donors in Shenzhen. 【Methods】 High pressure liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used to measure ART drugs concentrations in the plasma of regular blood donors (negative control group, n=86) and anti-HIV positive individuals (experimental group, n=98, detected from approximately 440 000 blood donors during 2019—2023). The baseline plasma concentrations of ART drugs in the negative control group were clarified, and the impact of ART drugs on blood safety was analyzed. 【Results】 The baseline concentrations of ART drugs were not detected in 86 samples of negative control group. Four positive ART drugs samples were detected in 1∶2 pooled plasma samples of 98 anti-HIV positive blood donors plasma in the resolution test. The ART positive rate of anti-HIV positive donors was 4.08%, with tenofovir, lamivudine and efavirenz detected in three blood donors and lamivudine, lopinavir, ritonavir and zidovudine detected in one blood donor. 【Conclusion】 ART drugs were found among anti-HIV positive blood donors in Shenzhen. Additional research is needed to investigate the motivation of these specific donors, so as to ascertain the groups most susceptible to potential risks, and guarantee blood safety.

Objective To analyze the correlation between the expression of soluble glycoprotein A(GPA)in plasma of healthy blood donors and anti-M and anti-"Mia"antibodies.Methods Plasma from healthy donors from February 9,2022 to February 15,2023 was collected:irregular antibody-negative NN type(group Ⅰ,n=118)and MM type(group Ⅱ,n=51),anti-M antibody positive NN type(group Ⅲ,n=145)and anti-"Mia"antibody positive companion type(group Ⅳ,n= 87),the GPA content in plasma of different individuals in 4 groups was detected,and the difference in GPA expression was analyzed by t-test.Results The average plasma GPA contents in groupsⅠ,Ⅱ,Ⅲ and Ⅳ were 9.941±0.252,10.97±0.256,5.139±0.129 and 4.28±0.139ng/ml,respectively.The average GPA content of groups Ⅰ and Ⅱ was higher,and the average GPA content of groups Ⅲ and Ⅳ was lower,and the differences were statistically significant(all P＜0.01).Conclusion The GPA content in plasma of healthy donors with anti-M and anti-"Mia"antibodies was significantly lower than that of the antibody-negative group.The results of this study lay a foundation for further investigation of whether GPA in plasma has the ability to neutralize anti-M and anti-"Mia"antibodies,improve disease diagnosis and safe blood transfusion.

Background::Atopic dermatitis (AD) affects approximately 10% of adults worldwide. CM310 is a humanized monoclonal antibody targeting interleukin-4 receptor alpha that blocks interleukin-4 and interleukin-13 signaling. This trial aimed to evaluate the efficacy and safety of CM310 in Chinese adults with moderate-to-severe AD.Methods::This multicenter, randomized, double-blind, placebo-controlled, phase 2b trial was conducted in 21 medical institutions in China from February to November 2021. Totally 120 eligible patients were enrolled and randomized (1:1:1) to receive subcutaneous injections of 300 mg CM310, 150 mg CM310, or placebo every 2 weeks for 16 weeks, followed by an 8-week follow-up period. The primary endpoint was the proportion of patients achieving ≥75% improvement in the Eczema Area and Severity Index (EASI-75) score from baseline at week 16. Safety and pharmacodynamics were also studied.Results::At week 16, the proportion of EASI-75 responders from baseline was significantly higher in the CM310 groups (70% [28/40] for high-dose and 65% [26/40] for low-dose) than that in the placebo group (20%[8/40]). The differences in EASI-75 response rate were 50% (high vs. placebo, 95% CI 31%–69%) and 45% (low vs. placebo, 95% CI 26%–64%), with both P values <0.0001. CM310 at both doses also significantly improved the EASI score, Investigator’s Global Assessment score, daily peak pruritus Numerical Rating Scale, AD-affected body surface area, and Dermatology Life Quality Index compared with placebo. CM310 treatment reduced levels of thymus and activation-regulated chemokine, total immunoglobulin E, lactate dehydrogenase, and blood eosinophils. The incidence of treatment-emergent adverse events (TEAEs) was similar among all three groups, with the most common TEAEs reported being upper respiratory tract infection, atopic dermatitis, hyperlipidemia, and hyperuricemia. No severe adverse events were deemed to be attributed to CM310. Conclusion::CM310 at 150 mg and 300 mg every 2 weeks demonstrated significant efficacy and was well-tolerated in adults with moderate-to-severe AD.Trial Registration::ClinicalTrials.gov, NCT04805411.

Objective:To investigate alterations in the glymphatic system of spinocerebellar ataxia type 3 (SCA3) patients based on quantitative MRI, and its association with genetic information and motor dysfunction.Methods:The study was a cross-sectional study. This prospective study recruited 39 confirmed SCA3 patients (SCA3 group) and 40 matched healthy controls (HC group) who were seen at the Southwest Hospital of Army Medical University from May 2017 to June 2023. All subjects underwent cranial MRI scanning. Clinical assessments were conducted on all participants using the scale for the assessment and rating of ataxia (SARA) and the international cooperative ataxia rating scale (ICARS). The automatic segmentation and volume measurement of the choroid plexus based on Freesurfer 6.0; the perivascular interstitial space (PVS) was automatically segmented based on the deep-learning model VB-Net, and the volume of the PVS in each brain region was quantified after manual correction. Independent samples t-test and Mann-Whitney U-test were used to analyze the changes in the class lymphatic system in the SCA3 group and the HC group. Pearson partial correlation analysis was used to explore the relationship between CAG repeats, the glymphatic system, and motor dysfunction. Results:The standardized choroid plexus volume in the SCA3 group was (1.24±0.36)×10 3 mm 3, and that in the HC group was (0.96±0.34)×10 3 mm 3, with a statistically significant difference ( t=4.01, P<0.001). PVS volumes in the frontal lobe, temporal lobe, parietal lobe, basal ganglia, cerebellum, thalamus, and brainstem regions in the SCA3 group were significantly higher than those of HC group ( P<0.05). Partial correlation analysis revealed that CAG repeats in SCA3 group were positively correlated with SARA, ICARS, and basal ganglia PVS volumes ( r=0.65, 0.58, 0.29; P=0.001, 0.001, 0.042). Cerebellar and temporal lobe PVS volumes were positively correlated with SARA ( r=0.59, 0.47; P=0.001, 0.003), and positively correlated with ICARS scores ( r=0.61, 0.40; P=0.001, 0.011). Choroid plexus volume was positively correlated with cerebellar and basal ganglia PVS volumes ( r=0.41, 0.31; P=0.009, 0.043). Conclusions:The glymphatic system of SCA3 patients have significant alteration and have association with CAG repeats and motor dysfunction.

Objective To investigate the application of intra pelvic pressure(IPP)in ultramicro-channel percutaneous nephrolithotripsy.Methods From January 2022 to January 2023,60 patients with urinary calculi who needed Super mini-PCNL(SMP)in The First Hospital of Jiaxing selected as the study objects.According to random number method,the patients were divided into control group and experimental group,with 30 cases.Both groups were treated with ultra-micro channel percutaneous nephrolithotripsia,while the experimental group was monitored and regulated IPP in real time during the operation,and observed and compared clinical indicators,IPP,fever,urinary protein,renal function,hemoglobin(Hb)and adverse reactions between the two groups.Results Compared with the control group,the hospitalization time of experimental group was shortened and the stone clearance rate was increased(P<0.05).The IPP levels of experimental groups at 6min,12min,24min and 36min were lower than those of control group(P<0.05).The fever of experimental group was lower than that of control group at 2d,3d,4d and 5d after operation(P<0.05).The urinary protein level of experimental group was lower than that of control group at 1d,2d,3d and 4d after operation(P<0.05).Compared with control group,blood urea nitrogen(BUN)and serum creatinine(SCr)levels of experimental group were decreased,and Hb levels were increased(P<0.05).The incidence of adverse reactions in experimental group was lower than that in control group(P<0.05).Conclusion Monitoring and adjusting intrapelvic pressure during super-mini percutaneous nephrolithotomy is beneficial in reducing postoperative fever in patients with urolithiasis,reducing urinary protein expression and kidney function damage,and controlling the occurrence of adverse reactions.It is worth recommending.

【Objective】 To analyze the results of different methods for reactive samples screened by the enzyme linked immunosorbent assay (ELISA) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in blood donors. 【Methods】 From March to April 2020, a total of 8 632 blood samples in Shenzhen were screened for SARS-CoV-2 total antibodies (TAb, including IgG, IgM, IgA) in plasma using ELISA(PC group), the antibody reactivity samples and their follow up plasma samples (FC group), and samples of disease control group(DC group) from January to April 2020 were detected using the following methods: 1) ELISA method for detecting IgG, IgM, and (or without detection) TAb; 2) pseudovirus neutralizing antibody test(pVNT); 3) western blot (WB) of SARS-CoV-2 antibody. The negative control group(NC group) from February to April 2020 performed ELISA and WB testing. 【Results】 Among the 34 total antibody positive samples, 2 were positive for pVNT test, and the total antibody, IgG and WB in the initial screening and tracking testing were positive. Thereafter, it was determined to be confirmed positive. The other 2 cases were positive for pVNT test, while the samples with positive WB results were in the follow-up stage. The TAb, IgG, and pVNT results did not conform to the dynamic evolution of antibodies, and cannot be determined as confirmed positive. 【Conclusion】 The infection status of antibody reactivity samples screened by SARS-CoV-2 ELISA can be judged by the logic of pVNT, WB and the dynamic change of antibody.