The engineering application of microbially induced carbonate precipitation(MICP)is limited by pH-dependent conformational dynamics of urease.Focusing on the α-subunit urease from Sporosarcina pasteurii,this study integrated conductivity experiments and constant-pH molecular dynamics simulations to analyze active site conformational dynamics and catalytic function across pH 3-11.Results showed that under neutral conditions(pH 7-8),key histidine residues(HIS139/HIS249)exhibited minimal dis-placement(＜0.5 ?),the longest hydrogen bond lifetime(＞8 ps),highest conformational stability(root mean square deviation,RMSD:0.15-0.18 nm),and optimal catalytic activity(conductivity change rate:0.03 mS/cm·min-1,CaCO3 precipitation:3.84 g).Extreme pH(pH 3/11)induced structural collapse(displacement up to 1.8 ?)and complete activity loss.Simulations revealed that neutral pH sta-bilizes a protonation-dependent cooperative allosteric network by maintaining active site cavity volume(～120 ?3)and moderate conformational coherence(correlation coefficient～0.8).This work deciphers the molecular mechanism of pH-regulated urease dynamics through protonation states,providing theoreti-cal support for MICP applications in acidic mine tailing remediation and alkaline soil stabilization.

The engineering application of microbially induced carbonate precipitation(MICP)is limited by pH-dependent conformational dynamics of urease.Focusing on the α-subunit urease from Sporosarcina pasteurii,this study integrated conductivity experiments and constant-pH molecular dynamics simulations to analyze active site conformational dynamics and catalytic function across pH 3-11.Results showed that under neutral conditions(pH 7-8),key histidine residues(HIS139/HIS249)exhibited minimal dis-placement(＜0.5 ?),the longest hydrogen bond lifetime(＞8 ps),highest conformational stability(root mean square deviation,RMSD:0.15-0.18 nm),and optimal catalytic activity(conductivity change rate:0.03 mS/cm·min-1,CaCO3 precipitation:3.84 g).Extreme pH(pH 3/11)induced structural collapse(displacement up to 1.8 ?)and complete activity loss.Simulations revealed that neutral pH sta-bilizes a protonation-dependent cooperative allosteric network by maintaining active site cavity volume(～120 ?3)and moderate conformational coherence(correlation coefficient～0.8).This work deciphers the molecular mechanism of pH-regulated urease dynamics through protonation states,providing theoreti-cal support for MICP applications in acidic mine tailing remediation and alkaline soil stabilization.

OBJECTIVES: To investigate the clinical treatment outcomes and the changes of the outcomes over time in extremely preterm twins in Guangdong Province, China. METHODS: A retrospective analysis was performed for 269 pairs of extremely preterm twins with a gestational age of <28 weeks who were admitted to the department of neonatology in 26 grade A tertiary hospitals in Guangdong Province from January 2008 to December 2017. According to the admission time, they were divided into two groups: 2008-2012 and 2013-2017. Besides, each pair of twins was divided into the heavier infant and the lighter infant subgroups according to birth weight. The perinatal data of mothers and hospitalization data of neonates were collected. The survival rate of twins and the incidence rate of complications were compared between the 2008-2012 and 2013-2017 groups. RESULTS: Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of severe asphyxia and smaller head circumference at birth (P<0.05). The mortality rates of both of the twins, the heavier infant of the twins, and the lighter infant of the twins were lower in the 2013-2017 group compared with the 2008-2012 group (P<0.05). Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of pulmonary hemorrhage, patent ductus arteriosus (PDA), periventricular-intraventricular hemorrhage (P-IVH), and neonatal respiratory distress syndrome (NRDS) and a higher incidence rate of bronchopulmonary dysplasia (P<0.05). CONCLUSIONS There is a significant increase in the survival rate over time in extremely preterm twins with a gestational age of <28 weeks in the 26 grade A tertiary hospitals in Guangdong Province. The incidences of severe asphyxia, pulmonary hemorrhage, PDA, P-IVH, and NRDS decrease in both the heavier and lighter infants of the twins, but the incidence of bronchopulmonary dysplasia increases. With the improvement of diagnosis and treatment, the multidisciplinary collaboration between different fields of fetal medicine including prenatal diagnosis, obstetrics, and neonatology is needed in the future to jointly develop management strategies for twin pregnancy.
Bronchopulmonary Dysplasia/epidemiology* ; Female ; Gestational Age ; Humans ; Infant ; Infant, Extremely Premature ; Infant, Newborn ; Pregnancy ; Respiratory Distress Syndrome, Newborn/epidemiology* ; Retrospective Studies ; Treatment Outcome

Sepsis， a common critical disease in the intensive care unit（ICU）， features high morbidity and mortality. At present， it is mainly tackled with western medicine， which may trigger a series of problems like antibiotic resistance， adverse hormonal reactions， and high cost after a long-term use. Therefore， exploring new efficient， safe， and cheap drugs and treatment modes has become the focus of our research at this stage. By virtue of unique advantages including "the concept of holism and individualized treatment based on syndrome differentiation"， Chinese medicine has accumulated quite rich experience in the prevention and treatment of sepsis. In recent years， research on the regulation of Chinese medicine on nuclear transcription factor-κB（NF-κB） signaling pathway in sepsis has kept emerging. On this basis， this paper reviewed the etiology and pathogenesis of sepsis， syndrome differentiation and treatment， NF-κB signaling pathway， and its intervention with Chinese medicine. It has been found that some single Chinese herbs and their extracts， Chinese herbal compounds， and Chinese herbal injections effectively inhibit the expression of such inflammatory factors as NF-κB-mediated tumor necrosis factor-α（TNF-α）， interleukin-1（IL-1）， and IL-6 as well as the related proteins， reduce the systemic inflammatory response and organ injury， and improve the prognosis by regulating the activation of NF-κB signaling pathway and the immune function of macrophages. However， due to the limitations of objective conditions， some studies also have the problems of fuzzy pro-inflammatory anti-inflammatory balance mechanism， unclear pharmacokinetics and low drug safety evaluation， which need to be further studied and explored in order to provide a new theoretical basis and diagnosis and treatment thinking for the treatment of sepsis with traditional Chinese medicine.

Objective To detect the expression of follicuLar helper T cells (Tfh) and interleukin-21 (IL-21) in the peripheral blood of patients with hepatic echinococcosis and healthy controls, so as to explore the associations of Tfh and IL-21 expression with the progression of hepatic echinococcosis. Methods Fifty cases of hepatic echinococcosis and healthy controls were collected from Qinghai Provincial People's Hospital, respectively. Flow cytometry was used to detect the expression of Tfh cells in the peripheral blood of hepatic echinococcosis patients and healthy controls, and enzyme-linked immunosorbent assay (ELISA) was used to detect serum IL-21 expression in hepatic echinococcosis patients and healthy controls. The correlation between Tfh cell expression and serum IL-21 level was examined in the patients with hepatic echinococcosis. Results Flow cytometry detected a higher percentage of CD4⁺CXCR5⁺ T cells (18.49% ± 5.67% vs. 16.18% ± 4.04%, P < 0.05), CD4⁺CXCR5⁺PD-1⁺ T cells (4.94% ± 1.91% vs. 2.29% ± 0.79%, P < 0.05) and CD4⁺CXCR5⁺ICOS⁺PD-1⁺ T cells (30.93% ± 24.10% vs. 21.07% ± 14.25%, P < 0.05) in hepatic echinococcosis patients than in healthy controls, and no significant difference was seen in the percentage of CD4⁺CRCR5⁺ICOS⁺ T cells between the patients and controls (0.29% ± 0.32% vs. 0.25% ± 0.31%, P > 0.05) . The serum IL-21 level was significantly higher in the patients with hepatic echinococcosis than in healthy controls ([ 293.35 ± 2 03.65) pg/mL vs. (192.72 ± 70.09) pg/mL, P < 0.05]; however, there was no correlation between the Tfh cell expression and serum IL-21 level in patients with hepatic echinococcosis (P > 0.05). Conclusion The expression of peripheral blood Tfh cells and serum IL-21 is elevated in patients with hepatic echinococcosis, and Tfh cells and IL-21 may contribute to the progression of hepatic echinococcosis.

Objective To evaluate the hypersusceptibility of Astragaloside injection on animal,and provide reference for clinical use with active systemic anaphylaxis (ASA),passive cutaneous anaphylaxis (PCA) and determination of serum sample titer.Methods ASA:Guinea pigs was ip with 0.4,1.6 mg/kg Astragaloside injection five times every other day.On the eleventh day after the last administration,the test substance was quickly injected to fore limb vein,and animal allergy symptoms were observed within 30 min.PCA:Astragaloside injection was ip injected to rats five times every other day and antiserum was collected.The antiserum was appropriately diluted,and sc injected to another group rats for passive sensitization.About 48 hours later,Astragaloside was quickly iv to rats,and the skin allergy was observed.Meanwhile,the antibody titer of the antiserum was determined.Results ASA:Astragaloside injection of 0.4,1.6 mg/kg in guinea pigs did not show any allergic reaction,that is,ASA was negative;PCA:Astragaloside injection of 0.5,2.0 mg/kg in rats did not show any allergic reaction,and Astragaloside specific antibodies were not determined in serum samples.That is,PCA was negative.Conclusion The results of ASA and PCA were negative in the experimental dose,and there was no specific antibody against Astragaloside in the serum prepared by PCA,which indicated that the possibility of hypersensitivity reaction was weak in clinical use.

WU polyomavirus (WUPyV), a new member of the genus Polyomavirus in the family Polyomaviridae, is recently found in patients with respiratory tract infections. In our study, the complete genome of the two WUPyV isolates (FZ18, FZTF) were sequenced and deposited in GenBank (accession nos. FJ890981, FJ890982). The two sequences of the WUPyV isolates in this study varied little from each other. Compared with other complete genome sequences of WUPyV in GenBank (strain B0, S1-S4, CLFF, accession nos. EF444549, EF444550, EF444551, EF444552, EF444553, EU296475 respectively), the sequence length in nucleotides is 5228bp, 1bp shorter than the known sequences. The deleted base pair was at nucleotide position 4536 in the non-coding region of large T antigen (LTAg). The genome of the WUPyV encoded for five proteins. They were three capsid proteins: VP2, VP1, VP3 and LTAg, small T antigen (STAg), respectively. To investigate whether these nucleotide sequences had any unique features, we compared the genome sequence of the 2 WUPyV isolates in Fuzhou, China to those documented in the GenBank database by using PHYLIP software version 3.65 and the neighbor-joining method. The 2 WUPyV strains in our study were clustered together. Strain FZTF was more closed to the reference strain B0 of Australian than strain FZ18.
Adult ; Child, Preschool ; China ; Evolution, Molecular ; Genome, Viral ; genetics ; Genomics ; Humans ; Male ; Molecular Sequence Data ; Phylogeny ; Polyomaviridae ; genetics ; isolation & purification ; Sequence Analysis, DNA ; methods

OBJECTIVETo evaluate the application of different variable number tandem repeats (VNTR) locus in genotyping of Mycobacterium tuberculosis (M.tuberculosis) strains isolated from eight provinces in China, and to find the suitable locus-set of VNTR for epidemical strains in China.

METHODSAll 140 M.tuberculosis strains were randomly selected from 2800 M.tuberculosis strains isolated from eight provinces in China, 27 VNTR loci were used for typing all isolates. Discriminatory power (Hunter-Gaston Index, HGI) of every locus and different locus-set were analyzed by BioNumerics software. Meanwhile, Spoligotyping was used to identify Beijing family and non-Beijing family. Then the HGI of different locus-sets in two families was also evaluated.

RESULTSAll 140 isolates were clustered into Beijing kindred (112 strains, 80%) and non-Beijing kindred (28 strains, 20%) by Spoligotyping. The discriminatory power of Spoligotyping in 140 isolates was 0.4589. Every locus showed different polymorphism and HGI were from 0 to 0.809. The number of VNTR loci with HGI higher than 0.5 in all strains, Beijing family and non-Beijing family was 8, 7 and 14 respectively. 27 loci were combined into four groups which included 8, 12, 15 and 24 VNTR loci respectively. Four locus-sets showed different polymorphism, HGI of eight-locus, 12-locus, 15-locus, and 24-locus set in 140 strains was 0.9991, 0.9882, 0.9980 and 0.9986, and their discriminatory power were calculated in Beijing kindred (HGI: 0.9987, 0.9318, 0.9969 and 0.9975) and non-Beijing kindred (HGI: 1, 0.9894, 1 and 1).

CONCLUSIONDifferent VNTR locus and locus-set showed different discriminatory power in the selected M.tuberculosis strains isolated from China. Eight-locus set can be used in molecular epidemiological study of M.tuberculosis in China after standardization.

Bacterial Typing Techniques ; DNA, Bacterial ; genetics ; Mycobacterium tuberculosis ; classification ; genetics ; isolation & purification ; Tandem Repeat Sequences

OBJECTIVETo investigate the differential gene expression of ependymomas.

METHODSFour fresh samples of ependymomas and 1 of normal brain tissue were collected during operation. The extracted total RNAs were converted as (32)P tagged cDNA probes, which were then hybridized with the Atlas Human Cancer Array, producing the array based hybridization maps following the protocol provided with the kit. A set of special software was applied to the analysis and RT-PCR was performed to test the result.

RESULTIn comparison with the normal brain tissue, there were 31 upregulated gene and 1 downregulated gene in ependymomas, most of which were firstly found to be differentially expressed in this kind of tumor.

CONCLUSIONThe discrepancy of gene expression profiles between ependymomas and normal brain tissues is highly put through and effectively detected with cDNA array, which provides new information for the further research on the molecular mechanisms of this lesion.

Brain ; metabolism ; Brain Neoplasms ; genetics ; Ependymoma ; genetics ; Gene Expression Profiling ; Humans ; Oligonucleotide Array Sequence Analysis ; Reverse Transcriptase Polymerase Chain Reaction

Objective To explore the effects of radiofrequency catheter ablation(RFCA)on the blood coaguable states and the clinical value of perioperative plasma D-dimer.Methods The plasma level of D-dimer was assayed by enzyme-linked immunosorbent assay(ELISA)in blood samples of 30 children who were undertaken RFCA.Blood samples were consecutively obtained before cannulating,after electrophysiologic(EP)study,immediately after RFCA,the second day and the seventh day after RFCA.The centrifuged spead was 3 000 r/min,keep it for 10 minutes to obtain the upper plasma,and the crvopreserve.Results The plasma levels of D-dimer was highest at the time point when RFCA was successfully accomplished and restored to preoperative level in the seventh day after RFCA.There were statistically significant difference in the paried values at different time points(Pa