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 evaluate the efficacy and safety of nebulized inhalation of recombinant human interferon (IFN) α1b injection in the treatment of respiratory syncytial virus (RSV) associated lower respiratory tract infections (pneumonia and bronchiolitis) in children.Methods:A randomized, double-blind, parallel, placebo-controlled add-on design was used.Children with pneumonia or bronchiolitis aged 2 months to 5 years who tested positive for RSV antigen within 72 hours of onset from 30 clinical trial sites including Beijing Children′s Hospital, Capital Medical University between February 2021 and December 2022 were included in this study and randomly divided into 2 groups at a ratio of 1∶1 based on a stratified-block method.Both groups received basic treatments such as cough control, asthma relieving, expectorant treatment, fever reduction, oxygen therapy, etc.The experimental group received additional nebulized inhalation of IFN α1b injection at a dose of 2.0 μg/(kg·time), twice a day.The control group received nebulized inhalation of placebo twice a day.Clinical efficacy was evaluated based on indicators such as the duration of clinical symptoms and signs, and the Kaplan-Meier method was used to calculate the median and 95% CI of the duration of clinical symptoms and signs.The Log-rank test was used to compared data between groups.Safety was assessed through the incidence of adverse reactions and laboratory tests, and the Chi-square test was used to analyze the difference between groups. Results:There were 123 children in the experimental group and 122 children in the control group.The median durations of all the 5 clinical symptoms and signs [including shortness of breath, wheezing, dyspnea (visible retractions), decreased transcutaneous oxygen saturation, and abnormal mental state] in the experimental group after treatment were slightly shortened than those in the control group [2.7 d(95% CI: 1.9-3.0 d)] vs.[2.9 d(95% CI: 2.6-3.6 d), P=0.027].The improvement in dyspnea (retractions) was especially pronounced in the experimental group, with a relief rate of 50.0% (0, 100%) on the first day of administration[compared with 0 (0, 50.0%) in the control group ( Z=2.002, P=0.025)].The median duration of dyspnea in the experimental group was nearly 1 day shorter than that in the control group [1.0 d(95% CI: 0.7-1.7 d) vs.1.8 d(95% CI: 1.0-2.5 d), P=0.046].There were no significant difference in hospital stay [6.0(5.0, 8.0) d vs.6.5(5.0, 8.0) d, Z=0.675, P=0.500], oxygen therapy duration [32.0(14.0, 96.3) h vs.39.0 (24.0, 83.2) h, Z=0.094, P=0.925], the recovery rate from clinical symptoms during treatment [(105/106, 99.1%) vs.(96/101, 95.0%)], and recurrence rate [(0/106, 0) vs.(2/101, 2.0%)] between the 2 groups (all P>0.05).However, the above-mentioned four indicators in the experimental group showed a trend of clinical benefits.The quantitative virus detection results showed that the RSV viral load in both groups decreased after treatment compared to before treatment.After 2 days of treatment, the decline rate of RSV viral load from the baseline was 0.90 lg copies/(mL·d) in the experimental group and 0.25 lg copies/(mL·d)in the control group, with a statistically significant difference ( P<0.05).Furthermore, there was no statistically significant difference in the incidence of adverse reactions between the 2 groups ( P>0.05).Importantly, no drug-related serious adverse reactions occurred in both groups. Conclusions:The nebulized inhalation therapy of IFN α1b demonstrates efficacy and safety in treating pediatric RSV associated lower respiratory tract infections.It particularly offers outstanding clinical therapeutic value for severe children.

Objective:To evaluate the efficacy and safety of nebulized inhalation of recombinant human interferon (IFN) α1b injection in the treatment of respiratory syncytial virus (RSV) associated lower respiratory tract infections (pneumonia and bronchiolitis) in children.Methods:A randomized, double-blind, parallel, placebo-controlled add-on design was used.Children with pneumonia or bronchiolitis aged 2 months to 5 years who tested positive for RSV antigen within 72 hours of onset from 30 clinical trial sites including Beijing Children′s Hospital, Capital Medical University between February 2021 and December 2022 were included in this study and randomly divided into 2 groups at a ratio of 1∶1 based on a stratified-block method.Both groups received basic treatments such as cough control, asthma relieving, expectorant treatment, fever reduction, oxygen therapy, etc.The experimental group received additional nebulized inhalation of IFN α1b injection at a dose of 2.0 μg/(kg·time), twice a day.The control group received nebulized inhalation of placebo twice a day.Clinical efficacy was evaluated based on indicators such as the duration of clinical symptoms and signs, and the Kaplan-Meier method was used to calculate the median and 95% CI of the duration of clinical symptoms and signs.The Log-rank test was used to compared data between groups.Safety was assessed through the incidence of adverse reactions and laboratory tests, and the Chi-square test was used to analyze the difference between groups. Results:There were 123 children in the experimental group and 122 children in the control group.The median durations of all the 5 clinical symptoms and signs [including shortness of breath, wheezing, dyspnea (visible retractions), decreased transcutaneous oxygen saturation, and abnormal mental state] in the experimental group after treatment were slightly shortened than those in the control group [2.7 d(95% CI: 1.9-3.0 d)] vs.[2.9 d(95% CI: 2.6-3.6 d), P=0.027].The improvement in dyspnea (retractions) was especially pronounced in the experimental group, with a relief rate of 50.0% (0, 100%) on the first day of administration[compared with 0 (0, 50.0%) in the control group ( Z=2.002, P=0.025)].The median duration of dyspnea in the experimental group was nearly 1 day shorter than that in the control group [1.0 d(95% CI: 0.7-1.7 d) vs.1.8 d(95% CI: 1.0-2.5 d), P=0.046].There were no significant difference in hospital stay [6.0(5.0, 8.0) d vs.6.5(5.0, 8.0) d, Z=0.675, P=0.500], oxygen therapy duration [32.0(14.0, 96.3) h vs.39.0 (24.0, 83.2) h, Z=0.094, P=0.925], the recovery rate from clinical symptoms during treatment [(105/106, 99.1%) vs.(96/101, 95.0%)], and recurrence rate [(0/106, 0) vs.(2/101, 2.0%)] between the 2 groups (all P>0.05).However, the above-mentioned four indicators in the experimental group showed a trend of clinical benefits.The quantitative virus detection results showed that the RSV viral load in both groups decreased after treatment compared to before treatment.After 2 days of treatment, the decline rate of RSV viral load from the baseline was 0.90 lg copies/(mL·d) in the experimental group and 0.25 lg copies/(mL·d)in the control group, with a statistically significant difference ( P<0.05).Furthermore, there was no statistically significant difference in the incidence of adverse reactions between the 2 groups ( P>0.05).Importantly, no drug-related serious adverse reactions occurred in both groups. Conclusions:The nebulized inhalation therapy of IFN α1b demonstrates efficacy and safety in treating pediatric RSV associated lower respiratory tract infections.It particularly offers outstanding clinical therapeutic value for severe children.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.

Objective:To investigate the pregnancy outcome and the maternal and infant follow-up in the puer-peral period(42 days after delivery)of cesarean section with SARS-CoV-2 Omicron variant in different periods of pregnancy.Methods:330 pregnant women who were diagnosed with SARS-CoV-2 infection and delivered by ce-sarean section in Guangdong Women and Children Hospital from November 20,2022 to January 25,2023 were selected as the research subjects.They were divided into the early(80 cases),middle(151 cases)and late(99 cases)pregnancy group according to the gestational age of infection.The general information,pregnancy compli-cations and comorbidities,pregnancy outcomes,and postpartum maternal and infant follow-up of each group of pregnant women were compared.Results:The clinical classification of pregnant women was asymptomatic and mild,with 9 cases of asymptomatic and 321 cases of mild.The incidence of gestational diabetes mellitus(GDM)in the early and late group was higher than that in the middle group(P＜0.05).There was no statistically significant difference in the incidence of placental abruption,fetal growth restriction,fetal distress,amniotic fluid contamina-tion,preterm labor,postpartum hemorrhage,macrosomia,low-birth-weight infants and the maternal intensive care unit(MICU)transfer rate,newborn birth weight,neonatal asphyxia rate and NICU transfer rate among the three groups(P＞0.05).The incidence of preterm rupture of membranes in the middle group was higher than that in the late group(P＜0.05).Puerperal follow-up results showed that there was no statistically significant difference in the incidence of poor maternal uterine incision healing,poor uterine involution,vaginal microecological imbal-ance and neonatal acute upper respiratory tract infection,pneumonia,digestive system disease,cardiovascular system disease among the three groups(P＞0.05).Conclusions:The majority of pregnant women with Omicron infection during pregnancy are mild.Omicron infection in different periods of pregnancy has no significant effect on pregnancy outcome and puerperal follow-up of cesarean section.No evidence was found that GDM and prema-ture rupture of membranes are significantly associated with Omicron infection in different periods of pregnancy.