An enzyme-displaying yeast as a whole-cell biocatalyst seemed an alternative to immobilized enzyme, due to its low-cost preparation and simple recycle course. Here, we tried to use a recombinant Pichia pastoris displaying Candida antarctica lipase B (CALB) to catalyze the synthesis of short chain flavor esters in n-heptane. We studied some major influential factors of esterification reactions, such as carbon chain length of the substrates, alcohol structure, enzyme concentration, substrates concentration, molar ratio of the substrates. The acid conversions were determined by titration and gas chromatography analysis. About ten kinds of esters were synthesized successfully, and the acid conversions of eight esters reached as high as 90% after reaction for 6 h. The result also indicated that ethanol and hexanoic acid were the most suitable substrates for this whole-cell catalyst. Under the optimal reaction conditions (the amount of lipase 20 g/L (306.0 U/g-dry cell), hexanoic acid concentration 0.8 mol/L, the molar ratio of hexanoic acid to ethanol 1:1.1), hexanoic acid conversion reached 97.3% after reaction for 1.5 h. To our knowledge, the CALB-displaying P. pastoris whole-cell biocatalyst showed good tolerance for high substrates concentration and exhibited high reaction rate on esterification of short chain flavor esters among the present enzyme/cell reported. Thus, CALB-displaying P pastoris whole-cell biocatalyst was promising in commercial application for flavor esters synthesis in non-aqueous phase.
Biocatalysis ; Candida ; enzymology ; Enzymes, Immobilized ; Esters ; metabolism ; Fungal Proteins ; Lipase ; biosynthesis ; genetics ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

Yeast surface display involves that the exogenous protein, which was fused with the yeast outer shell cell wall protein, was genetically anchored on the yeast cell surface. It has been widely used in expression and screening of functional protein. Here, we focused on the construction of lipase-displaying systems and its application in enzymatic biosynthesis, such as fatty acid methyl esters, short-chain flavour esters and sugar esters applications, and so on.
Candida ; enzymology ; genetics ; Lipase ; biosynthesis ; genetics ; Pichia ; enzymology ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Solvents ; Yeasts ; enzymology ; genetics

Objective To evaluate the association between short-term outcomes and collateral circulation status in patients with acute ischemic stroke receiving thrombolysis therapy.Methods Full-text articles published from January 2000 to November 2016 in Cochrane Library,Medline,Embase and Web of Science electronic database were retrieved and their quality was assessed.The association between short-term outcomes and collateral circulation status were analyzed by random-effects models.Results Twenty three studies involving 2 849 patients were included in quantitative synthesis.The results showed that good collateral circulations had a beneficial effect on favorable outcomes at 3 or 6 months (RR =2.26,95％ CI:1.85-2.77,P =0.00),and were also associated with a lower rate of symptomatic intracranial hemorrhage (RR =0.56,95％ CI:0.47-0.67,P ＜ 0.01) and a lower rate of mortality (RR =0.30,95％ CI:0.22-0.40,P ＜ 0.01).Conclusion The baseline collateral cimulation status is associated with the short-term outcomes in patients with acute ischemic stroke receiving thrombolysis therapy.

To investigate the value of apolipoprotein B to apolipoprotein AⅠ ratio combined with carotid intimamedia thickness in predicting acute cerebral infarction.Methods Patients with acute large artery atherosclerotic cerebral infarction in the anterior circulation who were hospitalized in the Department of Neurology，The First Affiliated Hospital of Xinjiang Medical University from July 2020 to June 2021 were selected as the case group.Patients with noncardiovascular and cerebrovascular diseases who were hospitalized during the same period were randomly selected as the control group.The clinical data and laboratory results of the two groups were compared，and the risk factors of acute cerebral infarction were analyzed.To explore the predictive value of apolipoprotein B to apolipoprotein AⅠratio combined with carotid intimamedia thickness in the incidence of cerebral infarction.The clinical data and laboratory results of the two groups were compared.The influencing factors of acute cerebral infarction were analyzed by logistic regression.The receiver operating characteristic curve was used to analyze the predictive value of the ratio of apolipoprotein B to apolipoprotein AⅠcombined with carotid intimamedia thickness in the incidence of cerebral infarction.Results The study included 143 patients with acute cerebral infarction and 122 patients with noncardiovascular and cerebrovascular diseases.Multivariate analysis showed that smoking（OR=3.448，95%CI 1.609-7.391），diabetes（OR=2.884，95%CI 1.389-5.989），carotid intimamedia thickness （OR=1.633，95%CI 1.219-2.189），Leukocytes （OR=1.258，95%CI 1.036-1.527），free fatty acids（OR=14.113，95%CI 1.942-102.558），ratio of apolipoprotein B to apolipoprotein AI（OR=10.896，95%CI 2.290-51.846），D Dimer（OR=4.690，95%CI 2.097-10.488），homocysteine（OR=9.594，95%CI 1.112-82.772） were independent risk factors for large atherosclerotic cerebral infarction.The value of the ratio of apolipoprotein B to apolipoprotein AⅠ [JP3]and carotid intimamedia thickness in predicting acute cerebral infarction was analyzed by receiver operating characteristic curve.The results showed that the area under the curve was 0.757（95%CI 0.699-0.816），the best predictive value was 0.466，the sensitivity was 81.8%，and the specificity was 58.2%.Conclusion The ratio of apolipoprotein B to apolipoprotein AⅠ and the carotid intimamedia thickness are related to the atherosclerotic cerebral infarction of the anterior circulation large arteries，and they have a certain value in jointly predicting the incidence of cerebral infarction.

To investigate the relationship between plasma lipoprotein a concentration and acute ischemic stroke in young people in Xinjiang.Methods 316 young acute ischemic stroke patients who were hospitalized in the Neurology Center of the First Affiliated Hospital of Xinjiang Medical University from July 2016 to December 2020 were selected as the young stroke group，and 637 young nonstroke patients hospitalized during the same period were randomly selected As a youth nonstroke group. The medical history and clinical data of all subjects were collected，and the relationship between plasma lipoprotein a concentration and the occurrence of acute ischemic stroke in young people was analyzed. Results The plasma lipoprotein a concentration in the youth stroke group［140.55 （208.88）］was significantly higher than that in the youth nonstroke group［95.00 （151.38）］.Comparing the plasma lipoprotein a concentration of the young stroke group and the young nonstroke group according to ethnicity，whether it is Han，Uygur or Kazakh，the plasma lipoprotein a concentration of the young stroke group is higher than that of the young non stroke group（P<0.05）. Multivariate logistic regression analysis indicated that lipoprotein a may be one of the independent risk factors for acute ischemic stroke in young people in Xinjiang（OR=1.601，95%CI 1.342～1.910，P<0.05）. Further explore the relationship between the concentration of plasma lipoprotein a and the occurrence of acute ischemic stroke in Han，Uygur，and Kazakh youths. It shows that the increase of lipoprotein a level in Han youth is significantly related to the occurrence of acute ischemic stroke in young people. 1.751 （95%CI 1.404～2.183，P<0.05）；with the increase of plasma lipoprotein a concentration，acute deficiency The risk of bloody stroke also further increased. The risk ratio of the study population at the highest quartile level to the study population at the lowest quartile level was 4.948 （95%CI 2.528～9.686，P<0.05）.However，in the Uygur and Kazakhs，there is no correlation between the concentration of lipoprotein a and the occurrence of acute ischemic stroke in young people.Conclusion The concentration of plasma lipoprotein a is associated with the occurrence of acute ischemic stroke in young people in Xinjiang. Further exploring the ethnic differences in the correlation，it is found that the plasma lipoprotein a concentration is closely related to the occurrence of acute ischemic stroke in the Han youth，and there is no correlation between the Uyghur and Kazakh youths.

【Objective】 To analyze the HIV-, HCV- and HBV- NAT yield rate in different areas of Henan province, so as to provide the basis for disease prevention and control as well as the establishment of a unified quality control standard for nucleic acid testing(NAT) in the Henan province. 【Methods】 The number and prevalence of NAT yielding samples with isolated infectious virus, namely HIV, HCV and HBV, in 18 blood stations in Henan province from 2017~2019, as well as the trends were analyzed. The NAT quality of each laboratory and each testing system was analyzed according to the ratio of reactive individual donation(ID) results to reactive minipools(MP). 【Results】 The HBV, HCV and HIV ID-NAT yield numbers in 3 501 251 blood donations were HBV 2 606(74/100 000), HCV 21 (0.63/100 000), and HIV 34(1.00/100 000). The HBV ID-NAT yield rate showed an upward trend in the whole province from 2017 to 2019, while the prevalence of HIV and HCV ID-NAT yield didn′t differ significantly during three years. 5 kinds of NAT detection systems were applied in 18 blood centers. among which Ⅰ, Ⅱ, Ⅳ and Ⅴ were triplex detection systems. 2661 ID-reactive samples were implicated in 5 595 MP-reactive samples, with a resolution rate of 47.56%. The resolution rate of triplex NAT system Ⅰ, Ⅱ, Ⅳ and Ⅳ was 39.63%~47.95%, 40.43%~54.36%, 51.61% and 70.00%~45.45%, respectively. An upward trend in triplex NAT resolution rate was observed in 8 laboratories, i. e.B, D, E, F, I, K, L and Q, and an descending trend in A and C. The NAT system Ⅲ, a ID-NAT system, was used only by laboratory C, presenting a NAT-yield rate of 0.19% (282/145 474) and resolution rate of 46.45% (131/282). 【Conclusion】 The majority of NAT-yield of one infectious virus in Henan province is HBV, presenting annual increasing trend. The quality management of NAT laboratories should be strengthened as the divergence was seen in the performance of different NAT laboratories.

【Objective】 To analyze the cause of single-ELISA reactive of four blood screening items in 18 blood stations in Henan, so as to provide the basis for improving the quality of blood screening. 【Methods】 The single-ELISA reactive rate of HBsAg, anti-HCV, HIV Ag/Ab and anti-TP of 18 blood station laboratories in Henan throughout 2019 was calculated, and the causes were analyzed according to different ELISA reagent combinations and gray area settings in each laboratory. 【Results】 The overall single-ELISA reactive rates of HBsAg, anti-HCV, HIV Ag/Ab and anti-TP were 1.740(2 154/1 237 789), 0.564‰(698/1 237 789), 1.421‰(1 759/1 237 789) and 1.561‰(1 932/1 237 789), respectively, showing significant differences by detection items (P <0.05). Person correlation analysis showed that the single-ELISA reactive rate was independent of the gray area settings.but dependent on laboratories and reagent combinations. The single-ELISA reactive rate of HBsAg, anti-HCV, HIV Ag/Ab and anti-TP in D laboratory was the highest and higher than that in other labs using the same reagent.The laboratories with high HBsAg single-ELISA reactive rate were mostly those using a combination of imported reagents and domestic reagents, including the top 6 laboratories. The laboratories with high anti-HCV single-ELISA reactive rate were mostly those using certain domestic reagents. No obvious rules was noticed by single-ELISA reactive for anti-HIV. Laboratories with high anti-TP single-ELISA reactive rate were mostly those using combination 4. 【Conclusion】 The HBsAg single-ELISA reactive rate was the highest in the four blood screening items of blood station laboratories in Henan. The single-ELISA reactive rate is related to the laboratory itself and the reagent manufacturer, suggesting that laboratory quality control should be strengthened and proper reagent combination should be selected to reduce the waste of blood.