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Objective To screen the conservative,stable and specific DNA signature sequence in the plasmid of Yersinia pestis.Methods Specific validation trials and stability of the qualification test were carried out to 40 strains of Yersinia pestis,47 strains of non-Yersinia pestis of home and wild types of rodent in Yunnan,by using 32 DNA sequences derived from Yersinia pestis in the plasmid and conventional PCR technology,and Yersinia pestis vaccine strain EV76 as a positive control.Results Four pairs of relatively conservative,stable and specific DNA marker genes were screened:YPMT1.05c,YPMT1.03c,YPMT1.42 and YPMT1.04c.Conclusions The 4 pairs of Yersinia pestis DNA signature sequences can be used for rapid diagnosis of plague.
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Objective To find methods to isolate and purify plasminogen activator (Pla) from artificial culture of Yersinia pestis. Methods Ultrasonication and urea extracting combined by ammonium sulfate salting-out were tried to extract Pla. High performance liquid chromatography(HPLC) was used to purify Pla. The first step was ion exchange and the second was gel filtration, Preparative electrophoresis was used to purify Pla, too. The enzyme activity of the isolated or purificated Pla was detected. Results Both 50% - 60% saturated ammonium sulfate deposition of supernatant of plague bacilli ultrasonication and 0 - 10% saturated ammonium sulfate deposition of supernatant of plague bacilli powder soaked by urea had three bands(Mr about 31×103, 35×103 and 37×103) and lysis rings were 6.5 and 7.2 mm in diameter respectively when the enzyme activity was detected. Pla purified by HPLC was mainly composed of three bands(Mr about 31×103, 35×103 and 37×103), occupying more than 80% of total protein weight and lysis ring was 5.0 mm in diameter. Pla purified by preparative electrophoresis mainly consisted of three bands(Mr about 31×103, 35×103 and 37×103) with other proteins of low concentration nearby, no lysis ring was detected. Conclusions Pla is collected by the methods of ultrasonication and urea extracting. Priliminary purification of Pla can be achieved by HPLC and preparative electrophoresis.
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Objective To compare the difference of biochemical characteristics and virulent Pst Ⅰ of Yersinia pestis strains in traditional focuses of plague in Yunna Province and in the new focuses of plague in Yulong County. Methods The identification data of biochemical characteristics(Rhamnose, Glycerol, Maltose, L-Arabina and Melibiose fermentation) and virulence factor(Pst Ⅰ) from different focuses of plague in Yunna Province were Retrospectively collected by tube test followed by the analysis using statistics software SAS 8.0 by Fisher exact probability of disordered two-way R × C table χ2 test. Results Among 48 strains of Yersinia pestis from hantaan type plague focus, 1 strain fermented L-maltose, 48 strains fermented Glycerol. Among 165 strains of Yersinia pestis from the Soul type plague focus, 1 strain did not ferment L-maltose, only one of them fermented Glycerol. 1 strain from the Soul type plague focus was confirmed to have mutation, for the test of nitrate reduction reaction was negative. All 5 strains of Yersinia pestis from the new focuses of plague in Yulong County fermented L-maltose and Glycerol. The statistical result showed that the differences in L-maltose and Glycerol fermentation of Yersinia pestis from different natural focuses of plague in Yunnan Province were statistically siguificant (P < 0.01). The differences of other biochemical characteristics and Pst Ⅰ were not statistically significant (P > 0.01). Conclusions Biochemical characteristics of Yersinia pestis from the hantaan type plague focus and the Soul type plague focus in Yunnan province are overlapping. Biochemical characteristics of Yersinia pestis from the new focuses of plague in Yulong County are different from those tradition focuses of plague in Yunna Province but share similarities to those from Unquiculatus focuses in North Tibet.
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BackgroundCoronavirus disease 2019 (COVID-19) is a global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). It has been found that coronary artery disease (CAD) is a comorbid condition for COVID-19. As the risk factors of CAD, whether blood lipids levels are causally related to increasing susceptibility and severity of COVID-19 is still unknown. DesignWe performed two-sample Mendelian Randomization (MR) analyses to explore whether dyslipidemia, low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), triglyceride (TG) and total cholesterol (TC) were causally related to COVID-19 risk and severity. The GWAS summary data of blood lipids involving in 188,578 individuals and dyslipidemia in a total of 53,991 individuals were used as exposures, respectively. Two COVID-19 GWASs including 1,221 infected patients and 1,610 severe patients defined as respiratory failure were employed as outcomes. Based on the MR estimates, we further carried out gene-based and gene-set analysis to explain the potential mechanism for causal effect. ResultsThe MR results showed that dyslipidemia was casually associated with the susceptibility of COVID-19 and induced 27% higher odds for COVID-19 infection (MR-IVW OR = 1.27, 95% CI: 1.08 to 1.49, p-value = 3.18 x 10-3). Moreover, the increasing level of blood TC will raise 14 % higher odds for the susceptibility of COVID-19 (MR-IVW OR = 1.14, 95% CI: 1.04 to 1.25, p-value = 5.07 x 10-3). Gene-based analysis identified that ABO gene was associated with TC and the gene-set analysis found that immune processes were involved in the risk effect of TC. ConclusionsWe obtained three conclusions: 1) Dyslipidemia is casually associated with the susceptibility of COVID-19; 2) TC is a risk factor for the susceptibility of COVID-19; 3) The different susceptibility of COVID-19 in specific blood group may be partly explained by the TC concentration in diverse ABO blood groups.