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TetR family transcriptional regulators (TFRs) are widely distributed in bacteria and archaea, and the first discovered TFR was confirmed to control the expression of tetracycline efflux pump in Escherichia coli. TFRs can bind DNAs and ligands. Small molecule ligands can induce conformational changes of TFRs, inhibiting or promoting TFRs to control target gene expression. Currently, TFRs have a wide variety of ligands, including carbohydrates, proteins, fatty acids and their derivatives, metal ions, and so on. Due to the diversity of ligands, TFRs regulate a wide range of physiological processes, from basic carbon metabolism and nitrogen metabolism to quorum sensing and antibiotic biosynthesis. On the basis of the recent studies in our laboratory and the literature, we review here the regulatory mechanism mediated by ligands of TFRs in primary and secondary metabolism, as well as the application of ligands for TFRs in the development of gene route and the activation of antibiotic biosynthesis.
Subject(s)
Anti-Bacterial Agents , Bacteria/metabolism , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Ligands , Quorum SensingABSTRACT
Objective@#To investigate the level of human blood basic fibroblast growth factor (FGF2) among children with autism spectrum disorder (ASD) and its correlation with behavioral phenotypes, to provide a reference for etiological research of ASD.@*Methods@#ASD Children were selected to get rehabitation training in reseach center of children development behavior in Harbin Medical University and the rehabitation constitution for ASD disabilities in Heilongjiang, 40 children were induded as ASD group, 41 healthy children in Harbin kindergarten was classified as control group. The Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS) and Peabody Picture Vocabulary Test (PPVT) were used to assess the severity and intelligence of ASD children, respectively.@*Results@#No difference was found in FGF2 level between ASD children (4.95 pg/mL) and normal children(8.51 pg/mL)（P>0.05). However, difference in FGF2 level between the two groups were found in 4-year-old group(P<0.05). The level of FGF2 differed across different severity and intelligence of ASD children(P<0.05).@*Conclusion@#Abnormal levels of FGF2 in ASD children may correlate with severity of autistic traits and intelligence of children.
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Objective To study the efficacy and safety of radiofrequency ablation combined with splenectomy in treatment of primary liver cancer with liver cirrhosis and hypersplenism.Methods Thirty patients with hepatocellular carcinoma complicated with liver cirrhosis and hypersplenism were treated in Fuyang People's Hospital from January 2016 to December 2017.These patients were randomly divided into the observation group (n =15) and the control group (n =15).Surgical liver resection combined with splenectomy was performed in the control group,and radiofrequency ablation combined with splenectomy was performed in the observation group.The time of thermal ischemia,operation time,intraoperative blood loss,blood transfusion volume,length of hospital stay,platelet level and liver function 1 week after surgery,and the incidences of postoperative complications and the overall survival rates 2 years after surgery were compared between the two groups.Results The operation times of the observation group and the control group were (89.1 ± 18.4 vs.118.9 ± 33.6) rin,blood loss (228.4 ± 120.5 vs.362.2 ± 159.5) ml,blood transfusion (192.3±112.4 vs.503.8±196.2) ml,and length of hospital stay (13.5±6.0 vs.21.9±11.6) d (all P＜0.05).After a week of operation,the indicators in the observation group were significantly better than the control group (all P＜0.05).The postoperative two-years complication rate in the observation group was 13.3％,which was significantly lower than the control group (46.7％,P＜0.05).There was no significant difference in the survival rates between the two groups two years after surgery.Conclusions Radiofrequency ablation combined with splenectomy for treatment of liver cancer with cirrhosis and hypersplenism effectively reduced postoperative complications,preserved liver function,increased platelet levels,improved hypersplenism,and was safer.It is a surgical method worthy of generalization.
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Objective:To assess the efficacy of trastuzumab combined with neoadjuvant chemotherapy in the treatment of human epidermal growth factor receptor-2 (Her-2)positive breast cancer patients,and to explore its influencing factors of prognosis of breast cancer.Methods:The clinical materials of 112 Her-2 positive breast cancer patients were collected and they were divided into combined treatment group (trastuzumab + neoadj uvant chemotherapy)and single chemotherapy group (without trastuzumab ). SPSS 1 9.0 software was employed to calculate and analyze their clinical characteristics.The survival rate and prognosis were analyzed by Kaplan-Meier method,Log-rank test, and Cox regression. Results:Among the 112 Her-2 positive breast cancer patients, 23 cases were treated with trastuzumab,89 cases were treated without trastuzumab.The disease-free survival (DFS)in combined treatment group and single chemotherapy group had significant difference (P=0.012).And there was no significant difference of overall survival (OS)between two groups (P=0.064).The HR negative group had 18 (32.7%)patients with 5-level of Miller and Payne (MP)classification which was higher than HR positive group (5/46,10.9%)(P=0.009).In univariate analysis,the tumor size,node status at diagnosis and node status after operation were the influencing factors of DFS in the Her-2 positive breast cancer patients;the tumor size,node status at diagnosis,MP classification and node status after operation were the influencing factors of OS in the Her-2 positive breast cancer patients.The result of multivariate analysis indicated that the tumor size, node status at diagnosis,and with or without radiotherapy were the independent influencing factors of DFS and OS in the Her-2 positive breast cancer patients. Conclusion:The breast lesions in the Her-2 positive breast cancer patients with negative HR are relieved after treated with trastuzumab combined with neoadjuvant chemotherapy. The combination of trastuzumab and neoadj uvant chemotherapy can significantly improve the DFS and has a positive influence in the prognosis of Her-2 positive breast cancer patients.
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Objective To investigate the risk factors of hepatitis B virus (HBV) reactivation after microwave ablation (MWA) and its prevention.Methods 72 patients who met the inclusion criteria were enrolled into the study.30 patients were in the control group and 42 patients in the prophylactic antivirus group.Results 8.3％ (6/72) patients developed HBV reactivation.A high HBV DNA load and no prophylactic antivirus therapy were independent risk factors of viral reactivation.Conclusion Prophylactic antivirus therapy can prevent HBV reactivation.
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Colorectal liver metastases (CRLM) are one of the main causes of death among the patients with colorectal cancer,yet most patients with CRLM are unable to get radical resection.Fortunately,thermal ablation can yield long-term survival efficacy in this population of CRLM patients.Currently,thermal ablation is the first-line treatment among other ablation technologies,including radiofrequency ablation and microwave ablation (MWA).However,recent advancements in microwave ablation techniques increase consideration of this method in the treatment of CRLM,such as:reliable,fast,efficient and rarely affected by heat-sink effect.This article aims to review the mechanism,efficacy,complications of MWA in treating CRLM.
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Objective To construct erythromycin-overproducing mutants by tandemly expressing S-adenosylmethionine synthetase gene metK, Vitreoscilla hemoglobin gene vhbS and pleiotropic regulatory gene adpA in Saccharopolyspora eryth-raea.Methods Through PEG-mediated protoplast transformation , the integrative plasmid carrying metK, vhbS and adpA was respectively introduced into erythromycin-producing wild-type strain S.erythraea A226 and industrial strain WB .The engineered strains were generated by apramycin resistance screening and PCR identification .The erythromycin production was compared in original strains and their mutants by the inhibition test of Bacillus subtilis and HPLC analysis .Results and Conclusion Four A226-derived mutants A226-P1-P4 and three WB-derived mutants WB-P1-P3 were independently obtained.Compared with wild-type strain A226, the relative erythromycin titer of the four engineered strains A 226-P1-P4 was increased from 8%to 25%by scoring the growth-inhibition zones .Further HPLC analysis showed that the four mutants had increased erythromycin A yield by 64%-94%.Likewise, the relative erythromycin titer and erythromycin A yield of the three engineered strains WB-P1-P3 were enhanced by 6%-10%and 31%-62%, respectively, in comparison with the original strain WB.The results show the universality of enhancing erythromycin productionvia tandem expression of metK, vhbS and adpA in S.erythraea.
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ObjectiveTo establish a method for measuring exhaled nitric oxide (eNO)concentrations in neonates with and without hypoxemic respiratory failure ( HRF), and to investigate the relationship between eNO and respiratory parameters in neonates with HRF. Methods Twenty-two newborn infants with HRF and 26 control neonates were included within the first 24 hours of postnatal life.Their eNO levels were detected with a rapid-response chemiluminescence analyzer daily during the first week of their postnatal life, and lung mechanics and gas exchange efficiency were monitored at the same time, such as pulse oxygen saturation ( SpO2 ), inspired fraction of oxygen ( FiO2 ) and other parameters.Wilcoxon Mann-Whitney U tests were used to compare eNO, SpO2/FiO2 and eNO/ ( SpO2/FiO2 × 100) in two groups. Pearson's correlation analyses were used to determine the relationships between eNO levels and indices of hypoxemic respiratory failure. ResultsDuring the first two days of postnatal life, eNO values of HRF neonates were higher than those of the control neonates[day 1,(7. 9 ± 3.2 )× 10-9 vs. (5.8 ±1.8)×10-9, P＜0.05;day2, (8.8±3.2)×10-9vs. (6.0±2.4)×10-9, P＜0. 05], butthere were no significant differences in the following days. With SpO2/FiO2 increasing, difference of eNO values between the HRF and non-HRF controls became narrowed, but there was still two fold difference of eNO/(SpO2/FiO2 × 100) on day 5-7. ConclusionsA method for measuring eNO was established and there was difference in neonates with and without HRF, which diminished with prolonged postnatal days, reflecting pathophysiological characteristics of HRF.
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Objective To establish a method of isolation, purification and identification of type Ⅱ alveolar epithelial cells (AEC- K ) from neonate piglet lungs of 1 ～ 3 days old and to investigate effects of proinflammatory cytokines on expression of growth factors (GFs). The yield, viability and purity of AEC- Ⅱ obtained using different enzyme digestion and purifying methods were compared. Methods After the first 24-hour culture of AEC- Ⅱ ,the media containing interleukin (IL)-1β,IL-6 and IGF-Ⅰ at different concentrations were used to culture AEC-Ⅱ for another 48 hours. And then the cells were counted and the expressions of insulin-like growth factor (IGF-Ⅰ ), platelet-derived growth factor ( PDGF), surfactant proteins (SP) -A and SP-B mRNA were determined by real time PCR. Results A significantly higher yield of AEC-Ⅱ was achieved by digesting the lung with 30 unit/ml elastase and 0.1 % trypsin at 37 t for 20 min, the yield was (5.33 ±0.54) × 106 after adjusted by the weight of lung and heart (P <0.01). The number of purified AEC-II obtained by immune adherence method was (38.0 ±28.0) × 106 perpiglet which was higher than by the method of percoll. The optimal phenotype maintenance time of AEC- Ⅱ was the first 24～96 hours in the primary culture. With increasing concentrations of IL-1 β and IL-6, there were decreased proliferation and expression of SP-A and IGF-Ⅰ mRNA in the cultured AEC- Ⅱ ,but SP-B mRNA expression was not affected. Both AEC-Ⅱ proliferation and expression of SP-A, SP-B mRNA decreased significantly after cultured with anti-IGF-Ⅰ. Conclusion In a new model of cultured AEC-Ⅱ from neonate piglets, IL-1β and IL-6 inhibited AEC- Ⅱ proliferation and SP-A mRNA expression through IGF-Ⅰ -dependent mechanisms.