Cerebral small vessel disease (CVSD) is a group of small vascular diseases involving small arteries,arterioles,small veins,venules,and capillaries.The imaging findings were lacunar infarction,cerebral microbleeds,cerebral white matter lesions,and perivascular space expansion.In recent years,the incidence of CSVD is increasing,which brings different degree of economic burden to the families and society.It becomes the focus of research at present.The permeability change of blood-brain barrier is the main reason for the onset of CSVD.This article reviews the relationship between the integrity of blood-brain barrier and CSVD.

Cerebral microbleeds (CMBs) are a key biomarker of cerebral small vessel disease on magnetic resonance imaging,They have potential clinical relevance to future stroke risk.Therefore,the detection of CMBs has important clinical significance for various cerebrovascular disease phenotypes.This article briefly summarizes the detection method of CMBs,mainly investigating the clinical significance of CMBs in general population and in patients with ischemic stroke,cerebral hemorrhage,vascular cognitive impairment,cerebral amyloid angiopathy,and leukoaraiosis.

AIM: To study the effects of hypothermia on the contents of AVP,Ang Ⅱ,L-EK,cAMP,Mg 2+ and Ca 2+ in rat plasma and different brain regions.METHODS: The model of experimental hypothermia rat was established and treated in groups randomly.At the end of the experiment,samples of plasma and braintissues were taken and the contents of L-EK,cAMP,AVP,Ang Ⅱ were determined by RIA methods,Mg 2+ and Ca 2+ by atom absorption methods.RESULTS: The contents of Ang Ⅱ,AVP increased significantly in the plasma of Ⅰ,Ⅲ group( P

Objective To prepare the Env-pseudotyped subtype B HIV-1 with enhanced green fluorescent protein ( EG-FP) gene,explore HIV-1 infection mechanisms and develop feasible methods of identification .Methods The Env-pseudo-typed viruses were packaged in HEK293T cells by cotransfection, and the reporter gene and P24 protein were detected by PCR, Western blot and ELISA .Reporter gene amplification , viral titration assay and a single round of infection assay were performed after the env-pseudotyped viruses infected HIV-1 permissive cell .Results and Conclusion A generation and identification method of the pseudotyped HIV-1 was established . The Env-pseudotyped subtype B HIV-1 has been prepared, which is able to infect SupT1 and TZM-bl cells through infection assay .

Objective:To investigate the predictive value of the PREMISE score for early death in Chinese patients with acute ischemic stroke (AIS).Methods:Patients with AIS admitted to the Department of Neurology, Lu'an people's Hospital from January 2019 to December 2019 were enrolled retrospectively. The demographic data and all baseline clinical data were collected, and compared between the early death group and survival group. Early death was defined as death within 7 days after admission. Multivariate logistic regression analysis was used to determine the independent influencing factors for early death in patients with AIS. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of PREMISE score for early death in patients with AIS. Results:A total of 919 patients with AIS were enrolled, 50 of them (5.4%) died early. Multivariate logistic regression analysis showed that fasting blood sugar (odds ratio [ OR] 1.157, 95% confidence interval [ CI] 1.004-1.334; P=0.044), higher National Institutes of Health Stroke Scale score ( OR 1.134, 95% CI 1.051-1.223; P=0.021) and the PREMISE score ( OR 4.047, 95% CI 1.276-12.836; P=0.018) were the independent risk factors for early death in patients with AIS. ROC curve analysis showed that the area under the curve of the PREMISE score predicting early death in patients with AIS was 0.899 (95% CI 0.866-0.931; P<0.001). When the cutoff value of the PREMISE score was 7, the sensitivity and specificity were 88.0% and 79.2%, respectively, the positive predictive value was 19.6%, and the negative predictive value was 99.1%. Conclusions:The PREMISE score has a good predictive value for early death in Chinese patients with AIS.

Bacitracin is a broad-spectrum polypeptide antibiotic, which is formed by 11 amino acids residues. Precursor amino acids supply might be the limit factor during bacitracin fermentation. First, our results demonstrated that increasing Ile and Leu supplies were regarded as the efficient strategies for the enhanced titer of bacitracin. Then, the amino acid permease YhdG, which was identified as the BCAA permease, was deleted and overexpressed in DW2, respectively. Our results showed that knocking out of permease YhdG could improve bacitracin production remarkablely. The bacitracin titer of the yhdG deficient strain DW2ΔyhdG reached 917.35 U/mL by flask fermentation, increased by 11% compared with that of DW2. In addition, the bacitracin titer was decreased by 25% in the YhdG overexpressed strain. Meanwhile, the intracellular concentrations of BCAA were higher than DW2 during the biosynthesis of bacitracin. The above results suggested that the permease YhdG might act as an exporter for branched chain amino acids in B. licheniformis DW2. Taken together, the increasing intracellular concentrations of branched chain amino acids by deleting amino acid permease YhdG could improve bacitracin titer. This study provided a new strategy for high-level production of bacitracin.

Bacitracin is a broad-spectrum antibiotics mainly produced by Bacillus, and is used as veterinary medicine in the fields of livestock and poultry breeding. Insufficient supply of precursor amino acids might be an important factor that hinders high-level microbial production of bacitracin. We investigated the effect of strengthening L-cysteine supply on bacitracin production by an industrial bacitracin producer, Bacillus licheniformis DW2. Overexpression of cysK encoding L-cysteine synthase led to a 9.17% increase of the bacitracin titer. Moreover, overexpression of cysE encoding L-serine acetyltransferase and cysP encoding thiosulfate/sulfate intracellular transporter increased the bacitracin titers by 7.23% and 8.52%, respectively. Moreover, overexpression of a putative cystine importer TcyP led to a 29.19% increase of intracellular L-cysteine, and bacitracin titer was increased by 7.79%. Subsequently, the strong promoter PbacA was used to replace the promoters of genes cysP, cysE and tcyP in strain DW2::ysK, respectively. The resulted strain CYS4 (DW2::cysK-PbacA-(cysP)-PbacA(cysE)- PbacA(tcyP) produced 910.02 U/mL bacitracin, which was 21.10% higher than that of the original strain DW2 (747.71 U/mL). Together with the experiments in 3 L fermenters, this research demonstrated that enhancing intracellular L-cysteine supply is an effective strategy to increase bacitracin production of B. licheniformis.
Amino Acids ; Bacillus licheniformis/genetics* ; Bacitracin ; Cysteine ; Metabolic Engineering

Bacitracin is a broad-spectrum cyclic peptide antibiotic, and mainly produced by Bacillus. Energy metabolism plays as a critical role in high-level production of target metabolites. In this study, Bacillus licheniformis DW2, an industrial strain for bacitracin production, was served as the original strain. First, our results confirmed that elimination of cytochrome bd oxidase branch via deleting gene cydB benefited bacitracin synthesis. Bacitracin titer and ATP content were increased by 10.97% and 22.96%, compared with those of original strain, respectively. Then, strengthening cytochrome aa3 oxidase branch via overexpressing gene qoxA was conducive to bacitracin production. Bacitracin titer and ATP content were increased by 18.97% and 34.00%, respectively. In addition, strengthening ADP synthesis supply is also proven as an effective strategy to promote intracellular ATP accumulation, overexpression of adenosine kinase DcK and adenylate kinase AdK could all improve bacitracin titers, among which, dck overexpression strain showed the better performance, and bacitracin titer was increased by 16.78%. Based on the above individual methods, a method of combining the deletion of gene cydB and overexpression of genes qoxA, dck were used to enhance ATP content of cells to 39.54 nmol/L, increased by 49.32% compared to original strain, and bacitracin titer produced by the final strain DW2-CQD (DW2ΔcydB::qoxA::dck) was 954.25 U/mL, increased by 21.66%. The bacitracin titer produced per cell was 2.11 U/CFU, increased by 11.05%. Collectively, this study demonstrates that improving ATP content was an efficient strategy to improve bacitracin production, and a promising strain B. licheniformis DW2-CQD was attained for industrial production of bacitracin.
Bacillus licheniformis ; metabolism ; Bacitracin ; biosynthesis ; Energy Metabolism ; genetics ; Industrial Microbiology ; methods