1.A multicenter study on respiratory pathogen detection with Mycoplasma pneumoniae pneumonia in children
Xiaoyan DONG ; Yingxue ZOU ; Fangfang LYU ; Wenhao YANG ; Hailin ZHANG ; Yanhua NIU ; Haojie WANG ; Run GUO ; Xu WANG ; Li LI ; Zihao LIN ; Li LUO ; Danli LU ; Quan LU ; Hanmin LIU ; Lina CHEN
Chinese Journal of Pediatrics 2024;62(4):310-316
Objective:To analyze the status of respiratory pathogen detection and the clinical features in children with Mycoplasma pneumoniae pneumonia (MPP). Methods:A prospective, multicenter study was conducted to collect clinical data, including medical history, laboratory examinations and multiplex PCR tests of children diagnosed with MPP from 4 hospitals in China between November 15 th and December 20 th, 2023. The multiplex PCR results and clinical characteristics of MPP children in different regions were analyzed. The children were divided into severe and mild groups according to the severity of the disease. Patients in the severe group were further divided into Mycoplasma pneumoniae (MP) alone and Multi-pathogen co-detection groups based on whether other pathogens were detected besides MP, to analyze the influence of respiratory pathogen co-detection rate on the severity of the disease. Mann-Whitney rank sum test and Chi-square test were used to compare data between independent groups. Results:A total of 298 children, 136 males and 162 females, were enrolled in this study, including 204 children in the severe group with an onset age of 7.0 (6.0, 8.0) years, and 94 children in the mild group with an onset age of 6.5 (4.0, 7.8) years. The level of C-reactive protein, D-dimer, lactic dehydrogenase (LDH) were significantly higher (10.0 (5.0, 18.0) vs. 5.0 (5.0, 7.5) mg/L, 0.6 (0.4, 1.1) vs. 0.5 (0.3, 0.6) mg/L, 337 (286, 431) vs. 314 (271, 393) U/L, Z=2.02, 2.50, 3.05, all P<0.05), and the length of hospitalization was significantly longer in the severe group compared with those in mild group (6.0 (6.0, 7.0) vs. 5.0 (4.0, 6.0) d, Z=4.37, P<0.05). The time from onset to admission in severe MPP children was significantly shorter than that in mild MPP children (6.0 (5.0, 9.5) vs. 9.0 (7.0, 13.0) d, Z=2.23, P=0.026). All patients completed the multiplex PCR test, with 142 cases (47.7%) MPP children detected with 21 pathogens including adenovirus 25 cases (8.4%), human coronavirus 23 cases (7.7%), rhinovirus 21 cases (7.0%), Streptococcus pneumoniae 21 cases (7.0%), influenza A virus 18 cases (6.0%). The pathogens with the highest detection rates in Tianjin, Shanghai, Wenzhou and Chengdu were Staphylococcus aureus at 10.7% (8/75), adenovirus at 13.0% (10/77), adenovirus at 15.3% (9/59), and both rhinovirus and Haemophilus influenzae at 11.5% (10/87) each. The multi-pathogen co-detection rate in severe MPP children was significantly higher than that in mild MPP group (52.9% (108/204) vs. 36.2% (34/94), χ2=10.62, P=0.005). Among severe MPP children, there are 89 cases in the multi-pathogen co-detection group and 73 cases in the simple MPP group. The levels of LDH, D-dimer and neutrophil counts in the multi-pathogen co-detection group were significantly higher than those in the simple MPP group (348 (284, 422) vs. 307 (270, 358) U/L, 0.8 (0.5, 1.5) vs. 0.6 (0.4, 1.0) mg/L, 4.99 (3.66, 6.89)×10 9vs. 4.06 (2.91, 5.65)×10 9/L, Z=5.17, 4.99, 6.11, all P<0.05). Conclusions:The co-detection rate of respiratory pathogens, LDH and D-dimer in children with severe MPP were higher than those with mild MPP. Among severe MPP children the stress response of children in co-detection group was more serious than that of children with simple MPP.
2.The role of Huaiqihuang Granules in the long-term management of bronchial asthma in young children: a multicenter real-world study
Huimin WANG ; Jinghui MU ; Chuanhe LIU ; Changshan LIU ; Ying WANG ; Zhiying HAN ; Xin SUN ; Xing CHEN ; Shuhua AN ; Dolikon MUZAPAR ; Aiping LU ; Min WANG ; Yan CHENG ; Xiaomei YIN ; Hanmin LIU ; Hong WANG ; Shan HUA ; Li DONG ; Ying HUANG ; Yi JIANG ; Jianxin XIONG ; Shenggang DING ; Wei WANG ; Shunying ZHAO ; Yuzhi CHEN
Chinese Journal of Applied Clinical Pediatrics 2023;38(4):286-290
Objective:To observe the role of Huaiqihuang Granules (HQ) in the long-term management of bronchial asthma in young children, and the effective effect on concomitant rhinitis.Methods:A prospective real-world multicenter study was conducted in children aged 2-5 years with asthma diagnosed in the outpatient department (from April 2016 to March 2019)who received either inhaled corticosteroid (ICS)/leukotriene receptor antagonist (LTRA)(control group); inhaled ICS/LTRA plus HQ(combination group), or HQ alone(HQ group). All patients were followed up at week 4, 8, 12 after treatment. The number of days with asthma symptoms, the frequency of severe asthma attacks, the level of asthma control, and the days with rhinitis symptoms in the last 4 weeks were recorded. Differences before and after treatment, and those among groups after treatment were compared using Kruskal- Wallis H test or Wilcoxon rank-sum test. Results:A total of 2 234 eligible patients were recruited, and 2 147 cases completed followed-up visits, including 477, 1 374 and 296 cases in the control group, combination group, and HQ group, respectively. After the treatment, all 3 groups showed significant declines in the days with asthma symptoms, frequency of severe asthma attack and the days with rhinitis symptoms (all P<0.01), and the rate of well-controlled asthma increased significantly ( P<0.01). It lasted until the end of follow-up. Among groups, patients in the combination group showed significantly less days of asthma symptoms than those of the other 2 group at week 8 and 12[0(0, 0.9) d vs.0(0, 0.3) d, P<0.05; 0(0, 0.1) d vs. 0(0, 1.0) d, P<0.01]. Patients in the combination group and HQ group showed a significantly lower rate of severe asthma attacks than that of the control group at week 12 [0(0, 1), 0(0, 1), 0(0, 2), all P<0.05]. The well-controlled rate of asthma in the combination group was significantly higher than that of the control group and HQ group at week 8 and 12 (89.6% vs. 85.9% vs.82.1%, H=15.28; 90.9% vs. 84.1% vs. 81.8%, χ2=29.32, all P<0.01). Conclusions:HQ can significantly alleviate symptoms of asthma and rhinitis, severe attack of asthma, and increase the control rate of asthma when used as an additional treatment or used alone.
3.An acute kidney injury risk prediction model for elderly patients with sepsis based on the intensive care medicine information database-Ⅳ
Jingjing ZHAO ; Fujin CHEN ; Ting CHEN ; Jing WANG ; Xiuhua SUI ; Hanmin FENG ; Li YAO
Chinese Journal of Geriatrics 2023;42(2):169-175
Objective:To explore the risk factors of acute kidney injury(stage 3)developed within 48 hours in elderly patients with sepsis, and to use them to develop a risk prediction model and then evaluate and externally validate the model.Methods:Clinical data of all elderly patients(age≥ 60 years)with sepsis in the intensive care medicine information database(MIMIC-Ⅳ v1.0)were extracted.Independent risk factors were determined by multivariate logistic regression analysis.A risk prediction model was constructed, a nomogram was drawn, and the receiver operating characteristic curve(ROC)and the Hosmer-Lemeshow(H-L)test were used to evaluate the model's prediction accuracy and R-squared.Clinical data of elderly patients(age≥ 60 years)with sepsis admitted to the Department of Critical Care Medicine of the Second People's Hospital of Hefei from May 2019 to October 2021 were retrospectively collected and fed into the prediction model to conduct external validation.Results:A total of 1 977 elderly patients with sepsis were screened out from the MIMIC-IV database and included in the training set, of whom, 544 developed AKI-stage 3 within 48 hours.Univariate analysis was performed for factors that might be associated with acute kidney injury in elderly patients with sepsis.Compared with the normal group that did not progress to AKI stage 3, there were statistically significant differences in 28 indicators, such as the duration of ICU stay, intravenous fluid intake in 24 hours, and use of vasoactive drugs[5(3, 9)d vs.7(4, 12)d; 2.05(1.17, 3.27)ml·kg -1·h -1vs.2.37(1.47, 4.10)ml·kg -1·h -1; 761(53.11%) vs.375(68.93%), P<0.001]. Based on the results of multivariate logistic regression analysis, a prediction model was finally constructed with 9 variables: albumin( OR=0.983, 95% CI: 0.966-0.999, P=0.040), aspartate transaminase( OR=1.000, 95% CI: 1.000-1.000, P<0.001), APTT( OR=1.005, 95% CI: 1.001-1.009, P=0.028), total bilirubin( OR=1.003, 95% CI: 1.001-1.004, P=0.001), serum creatinine( OR=1.005, 95% CI: 1.004~1.007, P<0.001), Charlson score( OR=1.117, 95% CI: 1.061-1.177, P<0.001), intravenous fluid intake in 24 hours( OR=1.101, 95% CI: 1.034-1.173, P=0.003), weight( OR=1.023, 95% CI: 1.018-1.029, P<0.001), and mechanical ventilation( OR=2.412, 95% CI: 1.843-3.157, P<0.001). Then a nomogram was generated.The area under the ROC curve(AUC)of the prediction model was 0.755(95% CI: 0.731-0.780), and the H-L test was conducted( χ2=10.89, P=0.208>0.05), indicating a good fit.Data from 102 elderly patients were included in the validation set, with 27 cases that had developed AKI-stage3 within 48 hours, and were fed into the prediction model, with an AUC of 0.778(95% CI: 0.676-0.880)and χ2=3.72 and P=0.882>0.05 from the H-L test, consistent with the results of the training set. Conclusions:The model has some predictive value for acute kidney injury in elderly patients with sepsis.
4.Expert consensus on nucleic acid amplification test of respiratory pathogens in children
Zhengde XIE ; Jikui DENG ; Lili REN ; Yan ZHANG ; Xiangpeng CHEN ; Hailin ZHANG ; Linqing ZHAO ; Baoping XU ; Lili ZHONG ; Qiang QIN ; Gen LU ; Yuejie ZHENG ; Deyu ZHAO ; Yunxiao SHANG ; Ling CAO ; Zhimin CHEN ; Yong YIN ; Hanmin LIU ; Adong SHEN ; Binwu YING ; Zhou FU ; Changchong LI ; Yuan QIAN ; Wenbo XU ; Jianwei WANG ; Kunling SHEN
Chinese Journal of Applied Clinical Pediatrics 2022;37(5):321-332
Acute respiratory tract infection is the most common infectious disease in children, which seriously threatens children′s health.Rapid and accurate etiological diagnosis is of great significance for the clinical treatment and control of these diseases.Pathogen nucleic acid test was applied and became the main method of respiratory tract infection diagnosis for its high sensitivity and specificity.To regulate the application of pathogen nucleic acid amplification test in respiratory tract infection in children, improve the diagnosis level, expert consensus on nucleic acid amplification test of respiratory pathogens in children was prepared to guide the application and promote pathogens diagnosis ability.
5.Analysis of cerebral infarction due to inherited dysplasminogenemia
Xuanyu CHEN ; Jingjing LIN ; Hanmin WANG ; Ruyi ZHOU ; Shuyue LOU ; Mingshan WANG ; Beilei HU
Chinese Journal of Neurology 2022;55(10):1111-1117
Objective:To investigate the relationship between inherited dysplasminogenemia and cerebral infarction (CI) by phenotype and gene mutation analysis of 2 inherited dysplasminogenemia pedigrees.Methods:Retrospective analysis was carried out on clinical data of 2 patients diagnosed with CI who were treated in the Department of Neurology, the First Affiliated Hospital of Wenzhou Medical University in January and March 2021, and peripheral venous blood samples were collected from proband 1 and his family members (8 subjects, 4 generations in total) and proband 2 and her family members (5 subjects of 3 generations in total), and their plasminogen (PLG) activity (PLG:A), protein C activity, protein S activity, antithrombin activity and the content of PLG antigen (PLG: Ag), fibrinogen, D-dimer and fibrinogen degradation products were measured for definite diagnosis. All 19 exons,5′ and 3′ untranslated regions of PLG were amplified with polymerase chain reaction, and the amplification products were analyzed by direct DNA sequencing. The results were compared with human PLG reference sequences published in the National Center for Biotechnology Information database using Chromas software to find the mutation sites, and confirmed by reverse sequencing.Results:Both of the 2 patients with confirmed CI had a young onset, and PLG: A was reduced to 21% in the proband 1 and to about 50% in 4 family members; PLG: A was reduced to about 50% in the proband 2 and 2 family members; PLG:Ag and the above tests were essentially normal in both probands and family members. Gene analysis showed that the proband 1 had the homozygous mutation of c.1858G>A in exon 15, the 4 family members of the proband 1, proband 2 and her 2 family members had the heterozygous mutation of c.1858G>A in exon 15, which resulted in a mutation of alanine at position 620 in PLG to threonine (p.Ala620Thr).Conclusions:The decrease of PLG:A was caused by the p.Ala620Thr missense mutation of PLG gene. Proband having CI may be related to the inhibition of fibrinolytic function in the organism due to the p.Ala620Thr missense mutation.
6.Expert consensus on clinical application of pulse oximetry in children
Yuejie ZHENG ; Adong SHEN ; Baoping XU ; Hanmin LIU ; Xing CHEN ; Lili ZHONG ; Guangmin NONG ; Gen LU ; Shenggang DING ; Zhiying HAN ; Yun SUN ; Qiang CHEN ; Yi JIANG ; Xiaoping ZHU ; Suping TANG ; Xiufang WANG ; Yong YIN ; Shuhua AN ; Ju YIN ; Fengxia XUE ; Xiaoli LIU ; Miao LIU ; Yonghong YANG ; Kunling SHEN
Chinese Journal of Applied Clinical Pediatrics 2022;37(23):1761-1772
Hypoxemia is a common complication of pneumonia, asthma, and bronchopulmonary dysplasia in children.Rapid identification of hypoxemia is of great significance for the disposal and management of critical children.Pulse oximetry is recognized by the World Health Organization as the best way to monitor hypoxemia in children, and it can monitor pulse oxygen saturation noninvasively and continuously.Based on the related literature at home and abroad, combined with the clinical needs of pediatrics, the " Expert consensus on clinical application of pulse oximetry in children" is formulated to improve the understanding of pediatricians and nurses on the application in pediatric clinical practice, principle, operation techniques, and limitations of pulse oximetry.
7.Study on knowledge, attitudes and practices of pulse oximetry among pediatric healthcare providers in China and their influencing factors
Fengxia XUE ; Yuejie ZHENG ; Adong SHEN ; Hanmin LIU ; Xing CHEN ; Lili ZHONG ; Guangmin NONG ; Xin SUN ; Gen LU ; Shenggang DING ; Yuanxun FANG ; Jiahua PAN ; Zhiying HAN ; Yun SUN ; Qiang CHEN ; Yi JIANG ; Xiaoping ZHU ; Suping TANG ; Xiufang WANG ; Changshan LIU ; Shaomin REN ; Zhimin CHEN ; Deyu ZHAO ; Yong YIN ; Rongfang ZHANG ; Ming LI ; Yunxiao SHANG ; Yaping MU ; Shuhua AN ; Yangzom YESHE ; Peiru XU ; Yan XING ; Baoping XU ; Jing ZHAO ; Shi CHEN ; Wei XIANG ; Lihong LI ; Enmei LIU ; Yuxin SONG ; Yonghong YANG ; Kunling SHEN
Chinese Journal of Applied Clinical Pediatrics 2022;37(23):1807-1812
Objective:To investigate the knowledge, attitudes, and practices (KAP) of pulse oximetry among pediatric healthcare providers in China and analyze the factor influencing the KAP.Methods:A self-developed questionnaire was used for an online research on the KAP of 11 849 pediatric healthcare providers from 31 provinces, autonomous regions, and municipalities of China from March 11 to 14, 2022.The factors influencing the KAP of pulse oximetry among pediatric healthcare providers were examined by Logistic regression. Results:The scores of KAP, of pulse oximetry were 5.57±0.96, 11.24±1.25 and 11.19±4.54, respectively.The corresponding scoring rates were 69.61%, 74.95%, and 55.99%, respectively. Logistic regression results showed that the gender and working years of pediatric healthcare providers, the region they were located, and whether their medical institution was equipped with pulse oximeters were the main factors affecting the knowledge score (all P<0.05). Main factors influencing the attitude score of pediatric healthcare providers included their knowledge score, gender, educational background, working years, region, medical institution level, and whether the medical institution was equipped with pulse oximeters (all P<0.05). For the practice score, the main influencing factors were the knowledge score, gender, age, and whether the medi-cal institution was equipped with pulse oximeters (all P<0.05). Conclusions:Chinese pediatric healthcare providers need to further improve their knowledge about and attitudes towards pulse oximetry.Pulse oximeters are evidently under-used.It is urgent to formulate policies or guidelines, strengthen education and training, improve knowledge and attitudes, equip more institutions with pulse oximeters, and popularize their application in medical institutions.
8.Consistency of peripheral whole blood and venous serum procalcitonin in children: a multicenter parallel controlled study
Quan LU ; Hong ZHANG ; Xiaoyan DONG ; Hanmin LIU ; Yongmei JIANG ; Yingxue ZOU ; Yongming SHEN ; Deyu ZHAO ; Hongbing CHEN ; Tao AI ; Chenggui LIU ; Zhaobo SHEN ; Junmei YANG ; Yuejie ZHENG ; Yunsheng CHEN ; Weigang CHEN ; Yefei ZHU ; Chonglin ZHANG ; Lijun TIAN ; Guorong WU ; Ling LI ; Aibin ZHENG ; Meng GU ; Yongyue WEI ; Liangmin WEI
Chinese Journal of Pediatrics 2021;59(6):471-477
Objective:To explore the consistency of peripheral whole blood and venous serum procalcitonin (PCT) levels, and the value of peripheral whole blood PCT in evaluating pediatric bacterial infection.Methods:This multicenter cross-sectional parallel control study was conducted in 11 children′s hospital. All the 1 898 patients older than 28 days admitted to these hospitals from March 2018 to February 2019 had their peripheral whole blood and venous serum PCT detected simultaneously with unified equipment, reagent and method. According to the venous serum PCT level, the patients were stratified to subgroups. Analysis of variance and chi-square test were used to compare the demographic characteristics among groups. And the correlation between the peripheral blood and venous serum PCT level was investigated by quantitative Pearson correlation analysis.The PCT resultes were also converted into ranked data to further test the consistency between the two sampling methods by Spearman′s rank correlation test. Furthermore, the ranked data were converted into binary data to evaluate the consistency and investigate the best cut-off of peripheral blood PCT level in predicting bacterial infection.Results:A total of 1 898 valid samples were included (1 098 males, 800 females),age 27.4(12.2,56.7) months. There was a good correlation between PCT values of peripheral whole blood and venous serum ( r=0.97 , P<0.01). The linear regression equation was PCT?venous serum=0.135+0.929×PCT peripheral whole blood. However, when stratified to 5 levels, PCT results showed diverse and unsatisfied consistency between the two sampling methods ( r=0.51-0.92, all P<0.01). But after PCT was converted to ordinal categorical variables, the stratified analysis showed that the coincidence rate of the measured values by the two sampling methods in each boundary area was 84.9%-97.1%. The dichotomous variables also showed a good consistency (coincidence rate 96.8%-99.3%, Youden index 0.82-0.89). According to the severity of disease, the serum PCT value was classified into 4 intervals(<0.5、0.5-<2.0、2.0-<10.0、≥10.0 μg/L), and the peripheral blood PCT value also showed a good predictive value (AUC value was 0.991 2-0.997 9). The optimal cut points of peripheral whole blood PCT value 0.5、1.0、2.0、10.0 μg/L corresponding to venous serum PCT values were 0.395, 0.595, 1.175 and 3.545 μg/L, respectively. Conclusions:There is a good correlation between peripheral whole blood PCT value and the venous serum PCT value, which means that the peripheral whole blood PCT could facilitate the identification of infection and clinical severity. Besides, the sampling of peripheral whole blood is simple and easy to repeat.
9.A multicenter retrospective study on the etiology of necrotizing pneumonia in children
Yunlian ZHOU ; Jinrong LIU ; Qiuwei YI ; Lina CHEN ; Zhiying HAN ; Changdi XU ; Suyan LIU ; Chuangli HAO ; Jing LIU ; Qiaoling LI ; Lijun WANG ; Chao WANG ; Guanghua CHE ; Yuanyuan ZHANG ; Lin TONG ; Yeqing LIU ; Shunying ZHAO ; Yuejie ZHENG ; Shu LI ; Hanmin LIU ; Jie CHANG ; Deyu ZHAO ; Yingxue ZOU ; Xinxing ZHANG ; Guangmin NONG ; Hailin ZHANG ; Jianli PAN ; Yanni CHEN ; Xiaoyan DONG ; Yunfeng ZHANG ; Yingshuo WANG ; Dehua YANG ; Quan LU ; Zhimin CHEN
Chinese Journal of Pediatrics 2021;59(8):658-664
Objective:To investigate the etiology of necrotizing pneumonia (NP) in children and the clinical characteristics of NP caused by different pathogens in China.Methods:A retrospective, case-control study was performed in children with NP who were admitted to 13 hospitals in China from January 2008 to December 2019. The demographic and clinical information, laboratory data, etiological and radiological findings were analyzed. The data were divided into three groups based on the following years: 2008-2011, 2012-2015 and 2016-2019, and the distribution characteristics of the pathogens in different period were compared. Meanwhile, the pathogens of pediatric NP in the southern and northern China were compared. And the clinical characteristics of the Mycoplasma pneumoniae (MP) NP and the bacterial NP were also compared. T-test or Mann-Whitney nonparametric test was used for comparison of numerical variables, and χ 2 test was used for categorical variables. Results:A total of 494 children with NP were enrolled, the median ages were 4.7 (0.1-15.3) years, including 272 boys and 222 girls. Among these patients, pathogens were identified in 347 cases and the pathogen was unclear in the remaining 147 cases. The main pathogens were MP (238 cases), Streptococcus pneumoniae (SP) (61 cases), Staphylococcus aureus (SA) (51 cases), Pseudomonas aeruginosa (13 cases), Haemophilus influenzae (10 cases), adenovirus (10 cases), and influenza virus A (7 cases), respectively. MP was the most common pathogen in all three periods and the proportion increased yearly. The proportion of MP in 2016-2019 was significantly higher than that in 2012-2015 (52.1% (197/378) vs. 36.8% (32/87), χ 2= 6.654, P=0.010), while there was no significant difference in the proportion of MP in 2012-2015 and that in 2008-2011 (36.8% (32/87) vs. 31.0% (9/29), χ2=0.314, P=0.575).Regarding the regional distribution, 342 cases were in the southern China and 152 in the northern China. Also, MP was the most common pathogen in both regions, but the proportion of MP was higher and the proportion of SP was lower in the north than those in the south (60.5% (92/152) vs. 42.7% (146/342), χ 2=13.409, P<0.010; 7.9% (12/152) vs. 14.3% (49/342), χ 2= 4.023, P=0.045). Comparing the clinical characteristics of different pathogens, we found that fever and cough were the common symptoms in both single MP and single bacterial groups, but chest pain was more common (17.0% (34/200) vs. 6.1% (6/98), χ 2=6.697, P=0.010) while shortness of breath and wheezing were less common in MP group (16.0% (32/200) vs. 60.2% (59/98), χ 2=60.688, P<0.01; 4.5% (9/200) vs. 21.4% (21/98), χ 2=20.819, P<0.01, respectively). The white blood cell count, C-reactive protein and procalcitonin in the bacterial group were significantly higher than those in the MP group (14.7 (1.0-67.1)×10 9/L vs. 10.5 (2.5-32.2)×10 9/L, 122.5 (0.5-277.3) mg/L vs. 51.4 (0.5-200.0) g/L, 2.13 (0.05-100.00) μg/L vs. 0.24 (0.01-18.85) μg/L, Z=-3.719, -5.901 and -7.765, all P<0.01). Conclusions:The prevalence of pediatric NP in China shows an increasing trend during the past years. MP, SP and SA are the main pathogens of NP, and the most common clinical symptoms are fever and cough. The WBC count, C-reactive protein and procalcitonin in bacterial NP are significantly higher than those caused by MP.
10.Heterologous expression and characterization of Aspergillus oryzae acidic protease in Pichia pastoris.
Xiaoping YUE ; Peng CHEN ; Yueming ZHU ; Yan ZENG ; Hanmin LIU ; Hongyan LIU ; Min WANG ; Yuanxia SUN
Chinese Journal of Biotechnology 2019;35(3):415-424
Acid protease, an important aspartic protease, has been widely used in food, pharmaceutical and tanning industries. To promote the research and application of acid protease, an acid protease gene (pepA) from Aspergillus oryzae was obtained from fermented soy based on metagenome sequencing, and then cloned and transformed into Pichia pastoris GS115 for heterologous expression. The characteristic of recombinant PepA was also investigated. The activity of acid protease in the culture supernatant of P. pastoris was 50.62 U/mL. The molecular mass of PepA was about 50 kDa, and almost no other proteins in the supernatant were observed, as shown by SDS-PAGE. The optimum pH and temperature of PepA were determined as pH 4.5 and 50 ℃. Mn²⁺ and Cu²⁺ enhanced the activity of PepA, whereas Fe³⁺, Fe²⁺ and Ca² had inhibitory effects on its activity. The above findings can provide guidance for heterologous expression and industrial application of acid protease from Aspergillus oryzae.
Aspergillus oryzae
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Cloning, Molecular
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Endopeptidases
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Hydrogen-Ion Concentration
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Pichia
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Recombinant Proteins
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Temperature

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